Archive for the ·

electronics

· Category...

Making an ARM Linux based computer from scratch

no comments

Over at Henrik Forstén’s blog, he has a write-up of his very impressive project where he designed, assembled, soldered and installed an BGA (Ball Grid Arry) ARM based board from scratch.

He discusses board design challenges with a four-layered PCB, considerations with traces for DDR2 RAM, CPU, and three voltage supplies. There are many pictures showing the soldering process. His summary is: “Many people say that soldering BGAs is hard but based on this experience I can’t agree. Maybe I just got lucky but I didn’t have any problems with them.”

Once the board is all put together, he goes on to boot Linux. That also proves somewhat tricky, and he ends up with a three-phase boot using an ARM bootloader, U-boot, and finally a custom built kernel.

He says, “I don’t really care about the usefulness of the board and this whole project is more of a learning experience”. Clearly it was a great success.

DealExtreme orders

no comments

DealExtrme, always useful stuff! Some of the things I’ve ordered, listed here so I can easily find it and order even more…

V117 Dual-Side SSOP16 / TSSOP16 / SOP16 SMD to DIP Adapter Boards Set - Green (2 PCS) E5YK Stainless Steel Aquarium Five Head Water Tank Regulating Valve - Black + Silver 5 x 5.5mm DC Power Extension Female Cable - Black (10 PCS) Male + Female DC Power Converter Connector Adapters w/ Terminal Blocks For CCTV Camera (Pair) Male + Female DC Power Converter Connector Adapters w/ Terminal Blocks for CCTV Camera (Pair) 1-to-2 Power Splitter Cable for CCTV Security System Camera (DC 12V) 5 x 5.5mm DC Power Extension Female Cable - Black + Silver (10 PCS) Aquarium Fish Tank Tubing Straight Connector T Splitter for 4mm Air Line (24 PCS) 5.5 x 2.5mm Plug AC Power Adapter - Black (AC 100~240V / EU Plug / 135cm-Cable) Ethernet Shield with Wiznet W5100 Ethernet Chip / TF Slot GM700 1.5 1298A 12.6V 9800mAh Rechargeable Li-ion Battery w/ US Plug Power Adapter Hubsan H107-A26 Body Shell for H107C R/C Quadcopter - Red + Black Hubsan H107-A21 Body Shell for H107C R/C Quadcopter - Red + Silver H107C-008 R/C Helicopter Replacement Blades for JD385, 310, 310B, YD928, F180, V252, H107, H107L Replacement 3.7V 500mAh 25C Lithium Polymer Battery for Hubsan H107 4-Axis - Blue + Black 0.9 XL7105-SY DIY 2.4GHz A7105 NRF24L01 Wireless Module for Arduino (2 PCS) 433Mhz RF Transmitter Module + Receiver Module Link Kit for Arduino / ARM /MCU WL - Green Hubsan H107C-A24 3.7V 380mAh Li-po Battery for H301C R/C Quadcopter - White 20906 6mm Silicone Hose - Translucent White (5.44m-Length) Hubsan H107-A02 Replacement Blades for X4 H107 Quadcopter - Black + White (4 PCS) E5YK Water Tank Adjusting / Regulating Valve - Black (10 PCS) E5YK Stainless Steel Aquarium Five Head Water Tank Regulating Valve - Black + Silver Desktop Wire Cord Cable Clip Organizer - Yellow + Green + Red (6-Piece) E5YK Aquarium Fish Tank 1-to-6 Air Splitter - White E5YK Water Tank Adjusting / Regulating Valve - Black (10 PCS) Aquarium Fish Tank Flexible Silicone Air Line Tube - Black (18m) 20903 Silicone Tube - Translucent White (5m) E5YK Inlet Air Pipe Air Control Valve for Fish Tank / Aquarium - Yellow (20 PCS) E5YK Aquarium Suction Cup Airline Tube Holders Clips - Transparent + White (10 PCS) DX 2014 Desk Calendar with 12 Months Hubsan X4 H107C 2.4G 4CH R/C Quadcopter w/ 0.3MP Camera - Black + Red (Mode 2) Protective PU Leather Case w/ Card Holder Slots for LG Nexus 5 - Deep Pink Protective PU Leather Flip-Open Case w/ Holder for Google Nexus 7 - Red Detachable 59-Key Bluetooth V3.0 Keyboard Case for Google Nexus 7 II - Blue M-013 Door Entrance Guard ID Card - White (10 PCS) 125K RFID Card Reader Module / RDM630 Series Non-Contact RF ID Card Module for Arduino - Green + Red 3.7V 350mAh 30C Li-ion Battery for Hubsan X4 RC Quadcopter + Walkera V120D06 - Silver Hubsan H107-A05 3.7V 240mAh Li-ion Polymer Battery - Black Hubsan R/C Spare Parts H107-A06 USB Charger for H107 / H107L R/C Quadcopter - Black Y-11 1 Female to 3 Male DC Power Splitter Adapter Cable - Black (35 cm) Male + Female DC Power Converter Connector Adapters w/ Terminal Blocks For CCTV Camera (Pair) Jtron Building Universal Terminal Block / Quick Connector 5 Holes / Wire Connector - Grey (5 PCS) 3P Universal PA6 Terminals - Grey + Red (10 PCS / 250V / 20A) 4-Channel 5V Optocoupler Isolation Relay Module w/ High Level Trigger - Blue Hubsan H107-A02 Replacement Blades for X4 H107 Quadcopter - Black + White (4 PCS) HSYY01 Micro Gear Water Pump Motor w/ Hose - White + Silver ENC28J60 Ethernet LAN / Network Module for 51 AVR STM32 LPC Ethernet Shield with Wiznet W5100 Ethernet Chip / TF Slot Jtron 0.36 HD2V04 HDMI to VGA + 3.5mm Audio Jack Converter Adapter Box - Black Universal AC Charger w/ Dual USB Output for Iphone / Ipad / Ipod - White (US Plug) USB 2.0 to Micro USB Charging Cable for Samsung / HTC / BlackBerry - White (200CM) Raspberry PI Acrylic Case - Transparent 5V 2A Wall Power Adapter for Scanner / Surveillance Camera + More (US Plug) W-1 E27 Automatic Rotating 3W 300lm Colorful RGB Light 3-LED Lamp for Decoration (85~265V) E14 6W 500lm 6500K White 15-SMD 5630 LED Light Bulb - White (220V) Lexin E14 4W 350lm 34-5050 SMD White Light Corn Lamp (220~240V) USB Terminal Power Adapter Voltage Current Tester - Grey + Black GH-10W 10W 430lm 9-LED Red + Blue Light Plant Grow Light Module - Silver + White (7.5~8V) Jtron 0.36 8-Channel 5V Relay Module Shield for Arduino (Works with Official Arduino Boards) JY-MCU 5V 3V IIC UART SPI Level 4-Way Converter Module Adapter HSYY01 Water Pump Motor w/ Hose - White + Silver 20906 6mm Silicone Hose - Translucent White (5.44m-Length) Aquarium Fish Tank Flexible Silicone Air Line Tube - Black (18m) E5HT Aquarium Air Tube - Transparent Blue (10m) Aquarium Fish Tank Tubing Straight Connector T Splitter for 4mm Air Line (24 PCS) E5YK Aquarium Fish Tank 1-to-6 Air Splitter - White USB Powered Flexible Neck 10-LED White Light Lamp - Blue (27cm) 4-Port High Speed USB 2.0 Hub - Black (60cm-Cable Length) Mini USB 4 Ports Hub 4-Port USB 2.0 HUB w/ Independent Switch - Black 5V 2A Universal Power Adapter Charger - Black (AC 100~240V / EU Plug / 3.5 x 1.35mm) Raspberry PI Acrylic Case - Transparent Protective Neoprene Bag Case for DSLR Camera Lens - Black (Size XL) Protective Neoprene Bag Case for DSLR Camera Lens - Black (Size L) HSYY01 Water Pump Motor w/ Hose - White + Silver W3-9 Immersible Water Pump for Miniature Garden - Off-white SZF280 PVC Mini Water Pump Motor - Beige Miniisw SW-015 1.5W Polysilicon Solar Panel - Black Miniisw SW-008 0.8W Solar Powered Battery Panel Board - Black Protective Jellyfish Pattern Silicone Back Case for LG E960 Nexus 4 - Multicolored Replacement Sound and Music Activated Spectrum VU Meter EL Visualizer - Smile Face (4*AAA) 5.5 x 2.5mm Plug AC Power Adapter - Black (AC 100~240V / EU Plug / 135cm-Cable) 1.5 5.5 x 2.5mm Plug AC Power Adapter - Black (AC 100~240V / EU Plug / 135cm-Cable) HDMI Female to Micro HDMI Male Adapter 40-Compartment Free Combination Plastic Storage Box for Hardware Tools / Gadgets - Translucent White 24-Compartment Free Combination Plastic Storage Box for Hardware Tools / Gadgets Panel Mount 10A 250V Fuse Holder - Black (5-Pack) Optical Triple Triangular Glass Prism Spectrum - White Dupont 4-Pin Female to Female Extension Wire Cable for Arduino (40cm / 10-Piece Pack) Dupont 4-Pin Male to Female Extension Wire Cable for Arduino (40cm / 10-Piece Pack) Universal DIY Bakelite Plate PCB Board - Brown (2-Piece Pack) Universal Glass Fiber PCB Board for DIY Project - Brown Prototype Universal Printed Circuit Board Breadboard - Brown (5-Piece Pack) Nano V3.0 AVR ATmega328 P-20AU Module Board + USB Cable for Arduino Nylon PP6 DC 12V 50mA Tact Switch - Black (100-Piece Pack) 1N4007 1000V 1A Unilateral Rectifier Diodes Set - Black + Silver (50 PCS) LM7805L 5V Voltage Regulator ICs (10 PCS) 2.54mm 1x40 Pin Breakaway Straight Male Header (10-Piece Pack) GP LR44 A76 1.5V Cell Button Batteries 10-Pack 5 x 20mm Glass Tube Fuse Set - Silver (100 PCS) LCD Keypad Shield for Arduino Duemilanove & LCD 1602 (Works with Official Arduino Boards) Protective Plastic Case for 3.5 635~645nm 800~1000MCD 5mm LED - Red (100-Piece Pack) 510~520nm 800~1000MCD 5mm LED - Green (100-Piece Pack) S1306 8-in-1 Gradual ABS Lens Filters + Lens Mount + Ring Set for 77mm Lens Camera - Black Unique Black 4 Series Armed Notebook - Rambo Knife (60-Page) Convenient Rectangle Sticky Note Memo Pads (4 x 100 Pieces) Stainless Steel 1/4 C2-07 Creative Inflatable Shoe Boot Support Spreader - Milk White (Pair) Double-Sided Glass Fiber Prototyping PCB Universal Board (12-Piece Pack) Double-Sided Glass Fiber Prototyping PCB Universal Board (3 x 7 / 5-Piece Pack) Prototype Universal Printed Circuit Board Breadboard - Green + Silver 3mm & 5mm Light-emitting Diode - Green + Red + Yellow (100-Piece Pack) Breadboard Jumper Wires for Electronic DIY (65-Cable Pack) 4 Channel 5V High Level Trigger Relay Module for Arduino (Works with Official Arduino Boards) 2-Channel Relay Shield Module for Arduino (Works with Official Arduino Boards) AMS1117 5V Power Supply Module Emolux 62mm Multi-Coated UV Lens Filter - Black Sound and Music Activated Multi-Mode Flashling EL Hearts T-shirt - M (3*AAA) Silica Gel Reusable Moisture-Proof Bead Desiccant - Blue Male + Female DC Power Converter Connector Adapters w/ Terminal Blocks For CCTV Camera (Pair) Universal Heavy Duty 6F22 9V Battery DSTE NB-7L Replacement 7.4V 1200mAh Battery for Canon G10 / G11 - G12 / SX30 IS - Grey 1/4 Universal Aluminum Alloy Straight Flash Bracket for Camera - Black Universal Aluminum Alloy Tripod Bracket for Speedlight / Camera- Black Universal Handheld Jar Opener White Magic Beans with Assorted Messages (10-Pack Growing Plant) Genuine Acecamp 2429 20L Outdoor Water Resistant Dry Bag - Yellow 1000mA Car Cigarette Powered USB Adapter/Charger (DC 12V/24V) DIY 433MHz Wireless Receiving Module for Arduino (Works with Official Arduino Boards) 433MHz Wireless Transmitter Module Superregeneration for Arduino DIY 16-Key AD Keypad Module - Blue 4 x 4 Matrix Switch Module - Green ES-71 II Lens Hood for Canon Mini Prototype Printed Circuit Board Breadboard for Arduino (5 PCS) Ceramic Capacitor for DIY Electronic Circuit - Red (270-Piece Pack) Solderless Breadboard with 400 Tie-Point (White) USB to RS232 Serial Port Adapter (Transparent Green) FreArduino Soil Humidity Sensor for Arduino (Works with Official Arduino Boards) Double-Sided Glass Fiber Prototyping PCB Universal Board (3 x 7 / 5-Piece Pack) DIY HR-202 Humidity Detection Sensor Module - Blue Aluminum Alloy Straight Hot Shoe Flash Bracket for Camera - Black Flash Diffuser for Canon 580 EX / EX II / YongNuo YN560 / YN565 Speedlite (3 PCS) HT RJ45 RJ11 Cable Tester Stainless Steel 1/4 Mini USB 2.4GHz 150Mbps 802.11b/g/n WiFi Wireless Network Card Adapter - Black USB 2.0 2.4GHz 802.11b/g/n 150Mbps WiFi/WLAN Wireless Network Adapter Ultra-Mini Nano USB 2.0 802.11n 150Mbps Wifi/WLAN Wireless Network Adapter 6.3V 3300uf Aluminum Motherboard Capacitors (20-Piece Pack) DIY ZIF DIP IC Socket Set - Green (8 PCS) Solder Tip Refresher 3-Pin Triode Transistor for DIY Project - Black (20 x 10-Piece Pack) Aluminum Electrolytic Capacitor for DIY Project (120-Piece Pack) DisplayPort DP Male to HDMI Female Adapter Cable - Black (15CM) Gold Plated 1080i HDMI V1.3 M-M Connection Cable (1M-Length) 11x12 132-Panel Brain Teaser Magic IQ Ball Micro USB To HDMI MHL Adapter - Black Gold Plated HDMI Male to DVI 24+1 Female Adapter 62mm Digital Camera Lens Cover Digital Camera Lens Cover/Cap with Strap for Canon (62mm) 7.4V 1200mAh Lithium Polymer Lipo Battery Pack for Lama or 4-CH R/C Helicopters HC-SR04 Ultrasonic Sensor Distance Measuring Module 4 x AA Battery Case Holder (3-Pack) Stainless Steel Triple Razor Blade Set (4-Pack) USB 2.0 Smart ID Card Reader - Silver 30cm Breadboard Wires for Electronic DIY (40-Cable Pack) Cree XR-E Q2 Emitter with Star 3W LED Emitter on Star (Multicolored RGB)

Proto boards and microcontrollers – an overview

Comments Off

MAKE magazine has a nice write-up of several of the popular micro controllers, prototyping and hobby boards out there. 36 of them in total. Of course, that covers only a fraction of all the brands, models and variations. That list runs much much longer.

Comments Off

DC-to-DC converters

Comments Off

There are a number of different DC-to-DC converters out there, used to convert between different voltage levels. Ranging from the small but inefficient linear regulators to switched-mode converters like the buck converter that can achieve 95% or even higher efficiency. Among the switched-mode converters there are quite a few variations based on different but often similar circuit topologies: The buck converter is a step-down converter, and as the name suggest its output voltage will be reduced from its input. A boost (step-up) converter has similar design, but will do the opposite. A buck-boost converter combines the two so output voltage can be converted from both higher and lower input voltage. However, the traditional buck-boost converter inverts the polarity, so that the output voltage is of the opposite polarity than its input. A single-ended primary-inductor converter (SEPIC) (aka. buck-boost SEPIC) solves that problem, and delivers fixed non-inverted output throughout the range of its input voltage.

If this is all a bit confusing, have a look at Julian Ilett’s excellent YouTube videos and reviews: He covers the SEPIC buck boost converter, and shows how it seamlessly goes from 0.5 to 30 V out on a 9V battery. He shows how a 400W boost converter can drive a 100W LED pad, and he has a review of several different buck converters, in fact several reviews. He also has many interesting videos on driving different LED boards, including 50W and 30W RGB. You’ll really have to watch all his 140 videos!

When it comes to buying these, DealExtreme of course has a lot on offer, but here it seems like eBay has a bigger variety across its different sellers. I’ve already ordered this one, and expect to get more in the future. In particular, one of the variations on the ZXY6005 (D) power supply looks like a must-have in a hobby workshop.

Comments Off

Fiber optics

Comments Off

For a long time I’ve been plotting to make a fiber optic “star” ceiling, however I’ve been put off by the prohibitively expensive offers on fiber, at around one Euro per meter for the 1.0 mm thickness. Enter The Fiber Optic Store, specialising exactly in star ceilings, they have a wide range of filaments (i.e. single threads as opposed to cables) available at custom lengths. For their bigger quantities, 1.0 mm comes down to about $0.40 / meter. They also have some interesting combo-backs, and even a small sampling offer to get an idea of the sizes.

Furthermore, they have a large FAQ and guide section with a well of information and tips. And finally, for the DIY illuminator, they have a bright idea on how to attach the fiber treads to a single LED. As seen in the picture below, they are kept in place by heat shrink tubing.

Comments Off

DealExtreme orders

Comments Off

Various items ordered from DealExtreme.

GH-10W 10W 430lm 9-LED Red + Blue Light Plant Grow Light Module - Silver + White (7.5~8V) Jtron 0.36 8-Channel 5V Relay Module Shield for Arduino (Works with Official Arduino Boards) JY-MCU 5V 3V IIC UART SPI Level 4-Way Converter Module Adapter HSYY01 Water Pump Motor w/ Hose - White + Silver 20906 6mm Silicone Hose - Translucent White (5.44m-Length) Aquarium Fish Tank Flexible Silicone Air Line Tube - Black (18m) E5HT Aquarium Air Tube - Transparent Blue (10m) Aquarium Fish Tank Tubing Straight Connector T Splitter for 4mm Air Line (24 PCS) E5YK Aquarium Fish Tank 1-to-6 Air Splitter - White USB Powered Flexible Neck 10-LED White Light Lamp - Blue (27cm) 4-Port High Speed USB 2.0 Hub - Black (60cm-Cable Length) Mini USB 4 Ports Hub 4-Port USB 2.0 HUB w/ Independent Switch - Black 5V 2A Universal Power Adapter Charger - Black (AC 100~240V / EU Plug / 3.5 x 1.35mm) Raspberry PI Acrylic Case - Transparent Protective Neoprene Bag Case for DSLR Camera Lens - Black (Size XL) Protective Neoprene Bag Case for DSLR Camera Lens - Black (Size L) HSYY01 Water Pump Motor w/ Hose - White + Silver W3-9 Immersible Water Pump for Miniature Garden - Off-white SZF280 PVC Mini Water Pump Motor - Beige Miniisw SW-015 1.5W Polysilicon Solar Panel - Black Miniisw SW-008 0.8W Solar Powered Battery Panel Board - Black Protective Jellyfish Pattern Silicone Back Case for LG E960 Nexus 4 - Multicolored Replacement Sound and Music Activated Spectrum VU Meter EL Visualizer - Smile Face (4*AAA) 5.5 x 2.5mm Plug AC Power Adapter - Black (AC 100~240V / EU Plug / 135cm-Cable) 1.5 5.5 x 2.5mm Plug AC Power Adapter - Black (AC 100~240V / EU Plug / 135cm-Cable) HDMI Female to Micro HDMI Male Adapter 40-Compartment Free Combination Plastic Storage Box for Hardware Tools / Gadgets - Translucent White 24-Compartment Free Combination Plastic Storage Box for Hardware Tools / Gadgets Panel Mount 10A 250V Fuse Holder - Black (5-Pack) Optical Triple Triangular Glass Prism Spectrum - White Dupont 4-Pin Female to Female Extension Wire Cable for Arduino (40cm / 10-Piece Pack) Dupont 4-Pin Male to Female Extension Wire Cable for Arduino (40cm / 10-Piece Pack) Universal DIY Bakelite Plate PCB Board - Brown (2-Piece Pack) Universal Glass Fiber PCB Board for DIY Project - Brown Prototype Universal Printed Circuit Board Breadboard - Brown (5-Piece Pack) Nano V3.0 AVR ATmega328 P-20AU Module Board + USB Cable for Arduino Nylon PP6 DC 12V 50mA Tact Switch - Black (100-Piece Pack) 1N4007 1000V 1A Unilateral Rectifier Diodes Set - Black + Silver (50 PCS) LM7805L 5V Voltage Regulator ICs (10 PCS) 2.54mm 1x40 Pin Breakaway Straight Male Header (10-Piece Pack) GP LR44 A76 1.5V Cell Button Batteries 10-Pack 5 x 20mm Glass Tube Fuse Set - Silver (100 PCS) LCD Keypad Shield for Arduino Duemilanove & LCD 1602 (Works with Official Arduino Boards) Protective Plastic Case for 3.5 635~645nm 800~1000MCD 5mm LED - Red (100-Piece Pack) 510~520nm 800~1000MCD 5mm LED - Green (100-Piece Pack) S1306 8-in-1 Gradual ABS Lens Filters + Lens Mount + Ring Set for 77mm Lens Camera - Black Unique Black 4 Series Armed Notebook - Rambo Knife (60-Page) Convenient Rectangle Sticky Note Memo Pads (4 x 100 Pieces) Stainless Steel 1/4 C2-07 Creative Inflatable Shoe Boot Support Spreader - Milk White (Pair) Double-Sided Glass Fiber Prototyping PCB Universal Board (12-Piece Pack) Double-Sided Glass Fiber Prototyping PCB Universal Board (3 x 7 / 5-Piece Pack) Prototype Universal Printed Circuit Board Breadboard - Green + Silver 3mm & 5mm Light-emitting Diode - Green + Red + Yellow (100-Piece Pack) Breadboard Jumper Wires for Electronic DIY (65-Cable Pack) 4 Channel 5V High Level Trigger Relay Module for Arduino (Works with Official Arduino Boards) 2-Channel Relay Shield Module for Arduino (Works with Official Arduino Boards) AMS1117 5V Power Supply Module Emolux 62mm Multi-Coated UV Lens Filter - Black Sound and Music Activated Multi-Mode Flashling EL Hearts T-shirt - M (3*AAA) Silica Gel Reusable Moisture-Proof Bead Desiccant - Blue Male + Female DC Power Converter Connector Adapters w/ Terminal Blocks For CCTV Camera (Pair) Universal Heavy Duty 6F22 9V Battery DSTE NB-7L Replacement 7.4V 1200mAh Battery for Canon G10 / G11 - G12 / SX30 IS - Grey 1/4 Universal Aluminum Alloy Straight Flash Bracket for Camera - Black Universal Aluminum Alloy Tripod Bracket for Speedlight / Camera- Black Universal Handheld Jar Opener White Magic Beans with Assorted Messages (10-Pack Growing Plant) Genuine Acecamp 2429 20L Outdoor Water Resistant Dry Bag - Yellow 1000mA Car Cigarette Powered USB Adapter/Charger (DC 12V/24V) DIY 433MHz Wireless Receiving Module for Arduino (Works with Official Arduino Boards) 433MHz Wireless Transmitter Module Superregeneration for Arduino DIY 16-Key AD Keypad Module - Blue 4 x 4 Matrix Switch Module - Green ES-71 II Lens Hood for Canon Mini Prototype Printed Circuit Board Breadboard for Arduino (5 PCS) Ceramic Capacitor for DIY Electronic Circuit - Red (270-Piece Pack) Solderless Breadboard with 400 Tie-Point (White) USB to RS232 Serial Port Adapter (Transparent Green) FreArduino Soil Humidity Sensor for Arduino (Works with Official Arduino Boards) Double-Sided Glass Fiber Prototyping PCB Universal Board (3 x 7 / 5-Piece Pack) DIY HR-202 Humidity Detection Sensor Module - Blue Aluminum Alloy Straight Hot Shoe Flash Bracket for Camera - Black Flash Diffuser for Canon 580 EX / EX II / YongNuo YN560 / YN565 Speedlite (3 PCS) HT RJ45 RJ11 Cable Tester Stainless Steel 1/4 Mini USB 2.4GHz 150Mbps 802.11b/g/n WiFi Wireless Network Card Adapter - Black USB 2.0 2.4GHz 802.11b/g/n 150Mbps WiFi/WLAN Wireless Network Adapter Ultra-Mini Nano USB 2.0 802.11n 150Mbps Wifi/WLAN Wireless Network Adapter 6.3V 3300uf Aluminum Motherboard Capacitors (20-Piece Pack) DIY ZIF DIP IC Socket Set - Green (8 PCS) Solder Tip Refresher 3-Pin Triode Transistor for DIY Project - Black (20 x 10-Piece Pack) Aluminum Electrolytic Capacitor for DIY Project (120-Piece Pack) DisplayPort DP Male to HDMI Female Adapter Cable - Black (15CM) Gold Plated 1080i HDMI V1.3 M-M Connection Cable (1M-Length) 11x12 132-Panel Brain Teaser Magic IQ Ball Micro USB To HDMI MHL Adapter - Black Gold Plated HDMI Male to DVI 24+1 Female Adapter 62mm Digital Camera Lens Cover Digital Camera Lens Cover/Cap with Strap for Canon (62mm) 7.4V 1200mAh Lithium Polymer Lipo Battery Pack for Lama or 4-CH R/C Helicopters HC-SR04 Ultrasonic Sensor Distance Measuring Module 4 x AA Battery Case Holder (3-Pack) Stainless Steel Triple Razor Blade Set (4-Pack) USB 2.0 Smart ID Card Reader - Silver 30cm Breadboard Wires for Electronic DIY (40-Cable Pack) Cree XR-E Q2 Emitter with Star 3W LED Emitter on Star (Multicolored RGB)

Comments Off

Adafruit order

Comments Off

Some items ordered from Adafruit a while back.

  • BeagleBone Black
  • GPIO Extender Cable for Raspberry Pi – 12″ long
  • MCP23017 – i2c 16 input/output port expander
  • MCP23008 – i2c 8 input/output port expander
  • Plastic Water Solenoid Valve – 12V – 1/2″ Nominal
  • Liquid Flow Meter – Plastic 1/2″ NPT Threaded
Comments Off

Tayda Electronics Order

1 comment

I previously wrote about Tayda Electronics, and their amazing prices on basic components. Just to try, I put in a small order, and it arrived by air less than two weeks later. The fact that you can order single components for the price of $0.01 is pretty amazing. Furthermore, they take the time and effort to put each type of item in its own little bag with a clear label. (As opposed to DealExtreme, which tend to lump things together and unlabelled.)

Mostly for my own reference, here’s the things I picked up. Some basic stuff, but most interesting was the MAX7219 LED segment driver for only $1.25. I’ll be using that in a project to control 64 LEDs, and hope to write about that shortly.

MAX7219 7 Segment + Dot Point -  Common Cathode serially interfaced display driver PDIP-24 LED 10mm Green Water Clear Ultra Bright - $0.10 LED 10mm Yellow Water Clear Ultra Bright - $0.10 LED 10mm Blue Water Clear Ultra Bright - $0.10 24 pin DIP IC Sockets Adaptor Solder Type - $0.08 0.1uF 50V 105C Radial Electrolytic Capacitor 5x11mm - $0.02 10uF 25V 105C Radial Electrolytic Capacitor 5x11mm - $0.02 Fuse Holder with Cover 5x20mm M205 PCB 15A - $0.16 Photo Conductive Cell Resistor LDR 650nm RADIAL KE-10720 - $0.24 40 Pin 2.54 mm Single Row Female Pin Header - $0.24 22pF 50V Ceramic Disc Capacitor - $0.01 10K OHM 1/4W 5% Carbon Film Resistor - $0.01 RGB LED 5mm Common Cathode - $0.27

Tayda Electronics

Comments Off

For a long time, Sparkfun and DealExtreme, and to a lesser extent Digikey and Adafruit have been my favourite shops for electronic components. Now I might have just found a new one: Tayda Electronics.

Their prices are in a completely different range than the aforementioned shops. Basic components like resistors and capacitors are one or two cents, or sometimes even less. Typically, you’d have to buy in bulk of 100 or even 1000 to get those prices, but at Tayda, you can order a single one, if you like.

Other highlights include 10mm LEDs like the ones I mentioned earlier, for 10 cents each (vs. $1 or more that I paid). In fact, the specs promise 14000-16000 mcd vs. the 5000 mcs I tried. I’ve ordered a few, and will post details later. Finally, the reason I came across their site: The Maxim Max7219 LED driver for $1.25 (vs. $10 or more at Sparkfun and others). That was really great news, since the magic seems to have gone out of chip I had, but disappointingly without magic smoke.

Their minimum ordering is $5, which might actually be difficult to reach with those prices. I’ve just put an order, and they promise same they shipping and about two weeks delivery with standard mail (at only ~$2 shipping cost). Let’s see how it goes.

Comments Off

8-pins jumper wires

1 comment

For a somewhat long running project, I was looking for 8-pin jumper wires, and had even gotten some headers and ribbon cable to see if I could make them myself. However, with the prospect of stripping, crimping and soldering some ~200 pins, it just didn’t happen. That’s why I was happy to find these pre-made cables from emartee.com. 4-pin and 5-pin wires are common, but except for Alibaba, I’ve not found 8 pins anywhere. They are available in lengths of 20, 30 and 60 cm. Ordering from emartee was smooth, and delivery from China was less than two weeks. Their prices are maybe slightly higher than what you find elsewhere, except for said 8 pin wires…

Below are just some fun pictures, with the last one hinting at the LED matrix project. More about that later.

More DealExtreme

Comments Off

A few months ago I listed what I’d bought and looked at on the Hong Kong based site DealExtreme. Here’s another overview, with more electronics and random stuff.

Ordered

Double-Sided Glass Fiber Prototyping PCB Universal Board (12-Piece Pack)Double-Sided Glass Fiber Prototyping PCB Universal Board (3 x 7 / 5-Piece Pack)Prototype Universal Printed Circuit Board Breadboard - Green + Silver3mm & 5mm Light-emitting Diode - Green + Red + Yellow (100-Piece Pack)Breadboard Jumper Wires for Electronic DIY (65-Cable Pack)4 Channel 5V High Level Trigger Relay Module for Arduino (Works with Official Arduino Boards)2-Channel Relay Shield Module for Arduino (Works with Official Arduino Boards)AMS1117 5V Power Supply ModuleEmolux 62mm Multi-Coated UV Lens Filter - BlackSound and Music Activated Multi-Mode Flashling EL Hearts T-shirt - M (3*AAA)Silica Gel Reusable Moisture-Proof Bead Desiccant - BlueMale + Female DC Power Converter Connector Adapters w/ Terminal Blocks For CCTV Camera (Pair)Universal Heavy Duty 6F22 9V BatteryDSTE NB-7L Replacement 7.4V 1200mAh Battery for Canon G10 / G11 - G12 / SX30 IS - Grey1/4Universal Aluminum Alloy Straight Flash Bracket for Camera - BlackUniversal Aluminum Alloy Tripod Bracket for Speedlight / Camera- BlackUniversal Handheld Jar OpenerWhite Magic Beans with Assorted Messages (10-Pack Growing Plant)Genuine Acecamp 2429 20L Outdoor Water Resistant Dry Bag - Yellow1000mA Car Cigarette Powered USB Adapter/Charger (DC 12V/24V)DIY 433MHz Wireless Receiving Module for Arduino - Green433MHz Wireless Transmitter Module Superregeneration for Arduino - GreenDIY 16-Key AD Keypad Module - Blue4 x 4 Matrix Switch Module - GreenES-71 II Lens Hood for CanonMini Prototype Printed Circuit Board Breadboard for Arduino (5 PCS)Ceramic Capacitor for DIY Electronic Circuit - Red (270-Piece Pack)Solderless Breadboard with 400 Tie-Point (White)USB to RS232 Serial Port Adapter (Transparent Green)Freaduino Soil Humidity Sensor for Arduino - WhiteDouble-Sided Glass Fiber Prototyping PCB Universal Board (3 x 7 / 5-Piece Pack)DIY HR-202 Humidity Detection Sensor Module - BlueAluminum Alloy Straight Hot Shoe Flash Bracket for Camera - BlackFlash Diffuser for Canon 580 EX / EX II / YongNuo YN560 / YN565 Speedlite (3 PCS)HT RJ45 RJ11 Cable TesterStainless Steel 1/4Mini USB 2.4GHz 150Mbps 802.11b/g/n WiFi Wireless Network Card Adapter - BlackUSB 2.0 2.4GHz 802.11b/g/n 150Mbps WiFi/WLAN Wireless Network AdapterUltra-Mini Nano USB 2.0 802.11n 150Mbps Wifi/WLAN Wireless Network Adapter6.3V 3300uf Aluminum Motherboard Capacitors (20-Piece Pack)DIY ZIF DIP IC Socket Set - Green (8 PCS)Solder Tip Refresher3-Pin Triode Transistor for DIY Project - Black (20 x 10-Piece Pack)Aluminum Electrolytic Capacitor for DIY Project (120-Piece Pack)DisplayPort DP Male to HDMI Female Adapter Cable - Black (15CM)Gold Plated 1080i HDMI V1.3 M-M Connection Cable (1M-Length)11x12 132-Panel Brain Teaser Magic IQ BallMicro USB To HDMI MHL Adapter - Black Gold Plated HDMI Male to DVI 24+1 Female Adapter62mm Digital Camera Lens Cover Digital Camera Lens Cover/Cap with Strap for Canon (62mm)

Interesting

Sound and Music Activated Velcro Spectrum VU Meter EL Visualizer T-shirt - Black (Size-L/4 x AAA)RM3 Hex KeyFlat Point Hex Key Screwdriver Set for Electronics DIY (8-Piece Set)RM2 Hex KeyRegal Tools 7-Piece Hex Keys Set7-Piece Set Hex Key Wrenches (0.7~3mm)Replacement Power Supply AC Adapter for Laptops - Black (5.5*2.1mm Plug Size)DIY CC1101 433MHz Wireless Transceiver Module for Arduino (2 PCS)8-Channel 5V Relay Module Shield for Arduino (Works with Official Arduino Boards)8 Channel Relay Module Extension Board for ArduinoDIY 4 x 4 16-Key Numeric Keypad - Black20 x 16 Double-Sided PCB Prototype Board for Arduino (Works with Official Arduino Boards)S1305 8-in-1 Gradual ABS Lens Filters + Lens Mount + Ring Set for 72mm Lens Camera - BlackMystery Speed Controller Pentium-30A for Brushless Motors (300/450 R/C Helicopters)FLYING 30A BEC Electronic Speed Controller for Brushless Motors (ESC)A2208-12T 1500KV Outrunner Brushless Motor1.6Prototype Universal Printed Circuit Board Breadboards - Green + Brown (10-Piece Pack)Prototype Universal Printed Circuit Board Breadboards - Yellow (10-Piece Pack)Prototype Universal Printed Circuit Board Breadboard - Golden (10-Piece Pack)4-Channel Relay Shield Module for Arduino (Works with Official Arduino Boards)Sound and Music Activated Velcro BEAT Spiral Dots EL Visualizer T-shirt - Black (Size-L/4 x AAA)37-in-1 Sensor Module Kit for Arduino (Works with Official Arduino Boards)9000 2.2RD32 720P 5MP Wide Angle Waterproof Action Video Camera with 8-LED White Light/AV Out/TF - YellowRD32 5.0 Mega Pixels HD 720P Waterproof Action Video Camera with 8-LED - Red (TF)1080P CMOS 5MP Sports Waterproof Digital Video Camera w/ 4x Digital Zoom/TV-Out/HDMI/SD (1.5UnisCom VP+309 Mini 1.1Transcend 8GB SDHC SD Card (Class 10 High Speed)3.3V / 5V Power Supply Module for MB102 Breadboard - BlackPower Black Wings Module Breadboard Adapter for Arduino (Works with Official Arduino Boards)MB102 Breadboard Power Supply Module for Arduino (Works with Official Arduino Boards)Power 3.3V / 5V Supply Module for MB102 Bread BoardFC-21 Power Expansion Board Module w/ Switch + Light Indication - Blue + BlackO-Shape Twin Flash Bracket for Macro Photography - BlackHigh Capacity 9800mAh Rechargeable External Battery - BlackFlexible 2-Mode Blue Light EL Strip (DC 12V/3M-Length)Rechargeable 9000mAh Li-ion Emergency Power Battery for Camcorder/Walkie Talkie/Camera + More12V 6800mAh Rechargeable Portable Emergency Power Li-ion BatteryPortable 6800mAh Emergency Rechargeable Battery Pack (EU Plug)12V 1800mAh Rechargeable Portable Emergency Power Li-ion Battery for CCTV Devices12V 6000mAh Rechargeable Portable Emergency Power Li-ion Battery12V 4800mAh Rechargeable Portable Emergency Power Li-ion BatteryPortable Dapper Stage Red/Green Laser Light Show - Blue + White (2 x AAA)Protective Plastic Case for 2.5Protective Plastic Case for 3.550mW Green + 100mW Red Laser Stage Lighting Projector with IR Remote + Tripod (100V~240V AC)Nano V3.0 for Arduino (Works with Official Arduino Boards)USB to RS232 Adapter Cable (1M-Length)RS232 Serial Port Express Card Adapter - Blue + Black + SilverPL2303HX Converter USB to TTL USB to COM Cable Module- Black (1m)Plastic Imine Membrane Screw Insulation Coat - White (1000 PCS)DIY 3mm Iron Hexagon Nut - Silver (200 PCS)2A Ceramic Tube Fuse Set (100-Piece Pack / 6 x 30mm)RGB LED Strip Control Box w/ IR 24-Key Remote Control (DC 12V)44-Key IR Remote Controller for LED Light Strip - WhiteStylish Anti-Slip Shoulder Strap for Canon DSLR Camera - RedMini Portable Metal Flash Holder Mount for Camera - BlackL-Shape Flash Bracket for Camera (2-Piece Set)Fotomate 250mm Movable Range 2 Way Macro Focusing Rail Slider433MHz 4-Channel Wireless Flash Trigger (1 x 12V 23A + 2 x AAA)433MHz 4-Channel Wireless Flash Trigger (1 x 12V 23A + 2 x AAA)Plastic Buckle Clip for High Power 220V SMD 3528 LED Flexible Strip - Transparent (10 PCS)DIY HR-202 Humidity Detection Sensor Module - Blue6490 DHT11 Humidity Temperature Sensor Module - Blue20 x 80mm Double-Sided PCB Prototype Boards (25 PCS)Double-Sided Glass Fiber Prototyping PCB Universal Board (10 x 16)Double-Sided Glass Fiber Prototyping PCB Universal Board (7 x 9)Electrical Bakelite Circuit Board (5x7cm/10-Piece)DS1307 I2C RTC DS1307 24C32 Real Time Clock Module for Arduino (Works with Official Arduino Boards)XL7105-SY DIY 2.4GHz A7105 NRF24L01 Wireless Module for Arduino (2 PCS)2.4GHz NRF24L01+ Wireless Communication Module for Arduino (2 PCS)DIY DS18B20 Stainless Steel Temperature Sensor Probe - BlackDHT21/AM2301 Capacitive Digital Temperature & Humidity Sensor - BlackENC28J60 Ethernet Module for Arduino (Works with Official Arduino Boards)HR31 Humidity Sensor Module for Arduino (Works with Official Arduino Boards)NRF905 Wireless Communication Transmission Module for Arduino (Works with Official Arduino Boards)2 Channel 4 Pins NC Type Shock Switch Sensor ModuleVibration Alarm Sensor Module for Arduino (Works with Official Arduino Boards)BMP085 Altimeter Atmospheric Pressure Module for Arduino (Works with Official Arduino Boards)Human Body Touch Sensor Module for Arduino (Works with Official Arduino Boards)DS1302 Real Time Clock Module with Battery CR2032DS18B20 Temperature Sensor - Black + SilverMicro SD Card Storage Memory Board Module for Arduino (Works with Official Arduino Boards)Digital Vibration Switch Sensor Module for Arduino (Works with Official Arduino Boards)Tilt Switch Sensor Module for Arduino (Works with Official Arduino Boards)3-Pin Light Sensor Module for Arduino (Works with Official Arduino Boards)DHT22 2302 Digital Temperature Humidity Sensor for Arduino (Works with Official Arduino Boards)DS18B20 Digital Temperature Sensor Module for Arduino (-55~125C)IR Receiver Module Wireless Remote Control Kit for Arduino (1 x CR2025)5V Relay Module for Arduino (Works with Official Arduino Boards)DHT11 Digital Temperature Humidity Sensor Module for Arduino (Works with Official Arduino Boards)Hall Effect Magnetic Sensor Module for Arduino (Works with Official Arduino Boards)MMA8451 3-Axial Triaxial Digital Accelerometer Module3-Axis Digital Gyroscope Sensor Module for Arduino (Works with Official Arduino Boards)

Disclaimer: All links are redirected to dx.com with my affiliated ID.

Comments Off

Tablet, tablet on the wall…

Comments Off

Tablet, tablet on the wall, what’s the cheapest of them all? That question comes up from time to time, so here’s the cheapest I could find at Deal Extreme. Please see the customer reviews for each product for details. And remember, you get what you pay for. At that price, it will work, run the browser and basic apps, but don’t expect “the gadget of the year”.

4.3″ Resistive Screen Android 4.0$43

7″ Capacitive Screen Android 4.1$62

10.1″ Capacitive Screen Android 4.0$169

Comments Off

DealExtreme

Comments Off

DealExtreme / dx.com is a Hong Kong gadget site with thousands and thousands of China products of all kinds, often at very competitive prices. Every order is free of shipping charges, even if you buy a $1 item. It makes it easy to order and forget. The only downside is the shipping time, which sometimes can be around three to four weeks; some things might arrive earlier, though.

Here are the items I’ve bought for myself and others so far, followed my wish list, or list of items which might be interesting. The order list can be download in CSV form, while the wish list had to be scraped. For what it’s worth, here is a small Python script which does that, plus a bash script for HTML rendering of image links and product descriptions.

The Python script uses WebDriver / Selenium, and install for that goes:
sudo apt-get install python-pip
sudo easy_install selenium

Orders

Genuine Acecamp 2429 20L Outdoor Water Resistant Dry Bag - Yellow1000mA Car Cigarette Powered USB Adapter/Charger (DC 12V/24V)DIY 433MHz Wireless Receiving Module for Arduino - Green433MHz Wireless Transmitter Module Superregeneration for Arduino - GreenDIY 16-Key AD Keypad Module - Blue4 x 4 Matrix Switch Module - GreenES-71 II Lens Hood for CanonMini Prototype Printed Circuit Board Breadboard for Arduino (5 PCS)Ceramic Capacitor for DIY Electronic Circuit - Red (270-Piece Pack)Solderless Breadboard with 400 Tie-Point (White)USB to RS232 Serial Port Adapter (Transparent Green)Freaduino Soil Humidity Sensor for Arduino - WhiteDouble-Sided Glass Fiber Prototyping PCB Universal Board (3 x 7 / 5-Piece Pack)DIY HR-202 Humidity Detection Sensor Module - BlueAluminum Alloy Straight Hot Shoe Flash Bracket for Camera - BlackFlash Diffuser for Canon 580 EX / EX II / YongNuo YN560 / YN565 Speedlite (3 PCS)HT RJ45 RJ11 Cable TesterStainless Steel 1/4Mini USB 2.4GHz 150Mbps 802.11b/g/n WiFi Wireless Network Card Adapter - BlackUSB 2.0 2.4GHz 802.11b/g/n 150Mbps WiFi/WLAN Wireless Network AdapterUltra-Mini Nano USB 2.0 802.11n 150Mbps Wifi/WLAN Wireless Network Adapter6.3V 3300uf Aluminum Motherboard Capacitors (20-Piece Pack)DIY ZIF DIP IC Socket Set - Green (8 PCS)Solder Tip Refresher3-Pin Triode Transistor for DIY Project - Black (20 x 10-Piece Pack)Aluminum Electrolytic Capacitor for DIY Project (120-Piece Pack)DisplayPort DP Male to HDMI Female Adapter Cable - Black (15CM)Gold Plated 1080i HDMI V1.3 M-M Connection Cable (1M-Length)11x12 132-Panel Brain Teaser Magic IQ BallMicro USB To HDMI MHL Adapter - Black Gold Plated HDMI Male to DVI 24+1 Female Adapter62mm Digital Camera Lens Cover Digital Camera Lens Cover/Cap with Strap for Canon (62mm)

Interesting

Portable Dapper Stage Red/Green Laser Light Show - Blue + White (2 x AAA)Protective Plastic Case for 2.5Protective Plastic Case for 3.550mW Green + 100mW Red Laser Stage Lighting Projector with IR Remote + Tripod (100V~240V AC)Arduino Compatible Nano V3.0USB to RS232 Adapter Cable (1M-Length)RS232 Serial Port Express Card Adapter - Blue + Black + SilverPL2303HX Converter USB to TTL USB to COM Cable Module- Black (1m)Plastic Imine Membrane Screw Insulation Coat - White (1000 PCS)DIY 3mm Iron Hexagon Nut - Silver (200 PCS)2A Ceramic Tube Fuse Set (100-Piece Pack / 6 x 30mm)RGB LED Strip Control Box w/ IR 24-Key Remote Control (DC 12V)44-Key IR Remote Controller for LED Light Strip - White24-Compartment Free Combination Plastic Storage Box for Hardware Tools / GadgetsRemovable Dividers 40-Compartment Plastic Storage for Small Gadgets36-Compartment Free Combination Plastic Storage Box for Hardware Tools / GadgetsEKB-108 Plastic Battery Box for 10 x AA / AAA - Translucent WhiteStylish Anti-Slip Shoulder Strap for Canon DSLR Camera - RedMini Portable Metal Flash Holder Mount for Camera - BlackL-Shape Flash Bracket for Camera (2-Piece Set)Aluminum Alloy Straight Hot Shoe Flash Bracket for Camera - BlackFotomate 250mm Movable Range 2 Way Macro Focusing Rail Slider1/4433MHz 4-Channel Wireless Flash Trigger (1 x 12V 23A + 2 x AAA)433MHz 4-Channel Wireless Flash Trigger (1 x 12V 23A + 2 x AAA)Plastic Buckle Clip for High Power 220V SMD 3528 LED Flexible Strip - Transparent (10 PCS)DIY HR-202 Humidity Detection Sensor Module - Blue6490 DHT11 Humidity Temperature Sensor Module - Blue20 x 80mm Double-Sided PCB Prototype Boards (25 PCS)Double-Sided Glass Fiber Prototyping PCB Universal Board (10 x 16)Double-Sided Glass Fiber Prototyping PCB Universal Board (7 x 9)Electrical Bakelite Circuit Board (5x7cm/10-Piece)Double-Sided Glass Fiber Prototyping PCB Universal Board (3 x 7 / 5-Piece Pack)DS1307 I2C RTC DS1307 24C32 Real Time Clock Module for Arduino - BlueXL7105-SY DIY 2.4GHz A7105 NRF24L01 Wireless Module for Arduino - Green (2 PCS)2.4GHz NRF24L01+ Wireless Communication Module for Arduino - Green (2 PCS)433MHz Wireless Transmitter Module Superregeneration for Arduino - GreenDIY 433MHz Wireless Receiving Module for Arduino - GreenDIY DS18B20 Stainless Steel Temperature Sensor Probe - BlackDHT21/AM2301 Capacitive Digital Temperature & Humidity Sensor - BlackENC28J60 Ethernet Module for Arduino - WhiteHR31 Humidity Sensor Module for Arduino - BlueNRF905 Wireless Communication Transmission Module for Arduino2 Channel 4 Pins NC Type Shock Switch Sensor ModuleVibration Alarm Sensor Module for Arduino - BlackBMP085 Altimeter Atmospheric Pressure Module for ArduinoHuman Body Touch Sensor Module for Arduino - Black + BlueDS1302 Real Time Clock Module with Battery CR2032DS18B20 Temperature Sensor - Black + SilverMicro SD Card Storage Memory Board Module for ArduinoArduino Compatible Digital Vibration Switch Sensor ModuleArduino Tilt Switch Sensor Module - BlackArduino Compatible 3-Pin Light Sensor Module - RedArduino Compatible DHT22 2302 Digital Temperature Humidity SensorDS18B20 Digital Temperature Sensor Module for Arduino (-55~125IR Receiver Module Wireless Remote Control Kit for Arduino (1 x CR2025)Arduino 5V Relay Module - Blue + BlackDHT11 Arduino Compatible Digital Temperature Humidity Sensor ModuleFreaduino Soil Humidity Sensor for Arduino - WhiteHall Effect Magnetic Sensor Module for Arduino (DC 5V)MMA8451 3-Axial Triaxial Digital Accelerometer ModuleArduino 3-Axis Digital Gyroscope Sensor Module - Blue

Comments Off

Home Automation on 433.92 MHz with Arduino

1 comment

Last year I wrote about my plans with the RF Link Transmitter, Receiver, and Everflourish home automation system seen in the pictures below. The idea was to replace the remote with my own system, and control the switches using the RF transmitter and an Arduino. However, the problem was to first decode the bespoke message sent from the remote so I could reproduce it. Initially, I was concerned that the RF receiver was giving a too noisy signal; only reading its value from the Arduino and printing to Serial.out did not yield anything useful. It was not before I took the Arduino out of the loop, and connected the receiver directly to a oscilloscope that things started to look more promising.

On the oscilloscope, I could see the message very clearly. Now I just had to write it down, and analyse the code for all different buttons and remotes. Here the problem was that each button sends a rather long message, 52 bits in total, and the old oscilloscope I tried did not have much memory to store recordings to. Also, it wasn’t mine, so was not so convenient to access and work with. Enter the real break-through of this story: Dave Houston brilliant idea and post about a poor man’s oscilloscope – your sound card! He works with various X10 systems himself, and has more interesting information on his site. For the sound-card hook-up, any audio-wire will do; if using a stereo wire and mono recording, figure out which side is which, add some resistors (39k and 10k was suggested; I ended up with one 1 k Ohm and another at 100 Ohm, which worked just as well). David also points out that the line-in should be used, rather than the microphone plug.

The next bright idea came from Ray, who has done exactly the same project as I wanted to do, but with a different remote control system. He shows how the open source audio tool Audacity can be used to record and analyse the message. I found that Audacity also had a neat feature in that you could add a Label Track, that made it easy to write down the code, and later export it, as seen below.

The screenshots below show a recorded signal in Audacity, first at an overview, then zoomed in, labelled, and finally marking the length of each segment. Notice in the first picture how there is a lot of noise before the remote button is pushed, but that it is very clear where a signal comes in (repeating four times). Also, as seen from the second picture, the signal is strong and clear, without much noise as all, which speaks for the quality of the RF receiver, I guess. In the third picture, the segments has been labelled; see below for how to extract that, and further details about the code.

Click on the pictures for larger versions.

Each of the remote control systems have their own proprietary encoding for the messages sent, and the Everflourish system I have has a very different code from Ray’s Stanley equipment. Each bit in the message is expressed by a high with varying length followed by a low of common length. In the last picture above, these segments have been labelled, and as can be seen, the long high is twice the length of the short (50 vs. 25 samples) while the low space is at 30 samples. That’s using a sample rate of 44100 Hz. Ray points out that you can zoom all the way in, and count the individual samples. Another way is to use the unit selection in Audacity (at the bottom of the window), and select the highest precision unit “hh:mm:ss + samples”, and then select the area of one segment. The start and end timing is then shown at the bottom of the window, and it’s a matter of simple subtraction to find the length. Much easier than counting 50 samples.

For the Everflourish code, only the highs matter then, so I recorded one button, cut out the relevant message, copy/pasted it to a new Audacity project, added a Label Track as seen from the menu above (Tracks -> Add New -> Label Track) and went through and labelled the highs with 0 for short and 1 for long. That was just an arbitrary choice. Once done, the new project was saved with a descriptive name of the remote and button, and the labels could be extracted from the XML project file with something like this. (As a bonus, the digits are split into 4-bit nibbles.)

cat remote1_button2_off.aup | grep label.*title | cut -d '"' -f 6 | tr -d '\n' | sed "s/\([01]\{4\}\)/\1 /g"

Below, the messages from three different remotes (with 4 + 4 + 8 = 16 buttons) are listed, but in the interest of space and simplicity, only some are shown. From this I conclude that only a few parts of the message are consistent between the different remotes. First, it always starts with a 0-nibble. The ON and OFF buttons are consistent and reversed across all buttons. Beyond that, it’s hard to tell what is encoded. There is possibly a marker in the middle, at the seventh nibble, marked in gray, but it could be a coincidence. The third nibble is also the same for all three remotes. As can be seen, the two first remotes share data in the first part, and one could be led to believe that this was a common preamble, but this must be rejected when looking at the third advanced remote.

That seems to go against what is assumed in the the source code from TellDus. There they assume a “house” and “unit” (button) key on the last nibbles before the on/off code, but that does not match what I see across my remotes. There seems to be nothing identifying a specific remote, but rather all buttons are unique, and there is possibly some kind of general batch (as opposed to unique serial) number at the beginning of the message.

Simple 4 button remote

1 - OFF : 0000 0110 0101 1010 1001 0110 0110 1001 0101 1010 1010 0101 0101
1 - ON  : 0000 0110 0101 1010 1001 0110 0110 1001 0101 1010 1010 1010 1010

2 - OFF : 0000 0110 0101 1010 1001 0110 0110 1001 0110 0101 0101 0101 0101
2 - ON  : 0000 0110 0101 1010 1001 0110 0110 1001 0110 0101 0101 1010 1010

3 - OFF : 0000 0110 0101 1010 1001 0110 0110 1001 1001 0110 0110 0101 0101
3 - ON  : 0000 0110 0101 1010 1001 0110 0110 1001 1001 0110 0110 1010 1010

Simple 4 button remote

1 - OFF : 0000 0110 0101 1010 1001 0101 0110 1001 0101 0110 1001 0101 0101
1 - ON  : 0000 0110 0101 1010 1001 0101 0110 1001 0101 0110 1001 1010 1010

2 - OFF : 0000 0110 0101 1010 1001 0101 0110 1001 0110 1000 1000 0101 0101
2 - ON  : 0000 0110 0101 1010 1001 0101 0110 1001 0110 1000 1000 1010 1010

3 - OFF : 0000 0110 0101 1010 1001 0101 0110 1001 1001 1010 0101 0101 0101
3 - ON  : 0000 0110 0101 1010 1001 0101 0110 1001 1001 1010 0101 1010 1010

Advanced 8 channel remote

1 - OFF : 0000 1010 0101 0101 0101 1010 0110 0101 0101 0110 0110 0101 0101
1 - ON  : 0000 1010 0101 0101 0101 1010 0110 0101 0101 0110 0110 1010 1010

2 - OFF : 0000 1010 0101 0101 0101 1010 0110 0101 0110 1001 1001 0101 0101
2 - ON  : 0000 1010 0101 0101 0101 1010 0110 0101 0110 1001 1001 1010 1010

Determining the length of each segment to be sent is done by looking at the sample rate. I used 44100 Hz, so the duration in micro seconds for the 30 sample space segment is 30 / 44100 * 1000000 = 680 µs. For the short 25 sample high, it is 567 µs, and double or 1134 µs for the long. When sending the message, I did not need to subtract anything from that, as Ray mentioned in his post. It is worth noting the initial high before the start of the message, and also at the end. Furthermore, it both starts and finishes with a low space, so whatever for-loop you create, one of these will be before or after. However, what is intriguing, is that all this can be reversed. That is, switch HIGH and LOW in the code, and the switches will still react. I’m guessing this is a robustness measure designed into the Everflourish system, but I have to admit that goes beyond my RF knowledge.

Finally, it’s worth mentioning the All On or All Off buttons. They simply send a series of messages for each of the buttons, repeating each button message four times before moving on to the next. When using the single on/off buttons, the message is also repeated four times for a short click.

And that’s all for now. I expect to round this project up with a post on the complete system, including communication from the computer, and some kind of Android application as a remote. Other ideas include auto-triggering the lights when detecting a pre-defined Bluetooth device, and possibly switching off in the absence of any device. Possibly some programmed behaviour during holidays, and pre-set configuration for certain situations, e.g. “movie setting”, “dinner time”, etc.

Revell Coaxial Helicopter

1 comment

I got my first helicopter this week, a Revell “Big One Pro” Coaxial 3 channel 2.4 GHz. At 100 Euros and only 3 channels, I was warned by the sales clerk that it was merely a toy, however, what are these models for if not to play with?

This model is so similar to the Double Horse 9053 Volitation, that I am assuming it is just re-braned by Revell. As far as I understand, the Double Horse line is made by Shuang-ma.

Comparing it to my AR.Drone which broke down last year, it has several interesting properties and features: Overall, I am impressed by the simplicity yet robustness of the frame construction, mechanics and electronics. Most of the frame is in what I assume is aluminium or magnesium, with a few parts of plastic in between. It feels solid, which a number of crashes have proved. The controller / main board is refreshingly simple, but also modular in the sense that motors and LEDs are JST plugged rather than soldered. Only the battery connector and power switch is soldered directly onto the board. This looks very promising as a platform to experiment with.

Apart from the basic electronic components, there are only three interesting chips: The radio receiver; what I assume is the main chip (designated 9118) and a vertically mounted chip, some kind of gyro maybe? Compared to the AR.Drone, refreshingly simple. Shuang-ma charges $15 for a replacement board, and they seem to be available many other places as well.

The battery is a 7.4 V 1300 mAh 2 sell LiPo, with brand name Tianpeng. Revell sells a spare one for 22 Euros, but I found a similar at DealExtreme for $10.5 so ordered that. Then Hobby King has a 1000 mAh for $3.5 so could try that as well.

Finally, the two main motors are designated 9093. I cannot see any make, but they look similar to this Syma Dragonfly. It would be interesting to find more specs on those.

So, I’ve been given a lot of praise. Are there any down-sides? Well, yeah. First, the plastic hull or shell is of the most fragile kind. After the first flight and crash, there was already a crack. And on the second day a big piece came off. So now I’ve used all the electrical tape I could find and taped it all together. It doesn’t look so nice, but at least it will not crack so easily. I considered removing the hull altogether, however it does protect the LiPo from taking a direct hit in a crash, which is probably good enough reason for keeping it. Once I get into changing a lot of batteries, I might reconsider that, though.

Speaking of batteries again. Five minutes flight time a couple of times a day is not too much fun. In fact, it is rather poor. As mentioned, I’ve already ordered more, but I wonder if it would be possible to combine some for a bit longer flight time as well.

Finally, on negative notes, the axis for the lower rotor come loose quite often, after a few crashes. I just have to tighten the two screws attaching the lower gear, but is still a bit annoying. Maybe there’s a better solution to that.

Overall, I think it was a good buy. Had some fun already, and hoping for plenty of more. Then there are several potential projects and thinking to get into, and repairs to make.