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Sparkfun orders

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Here’s a list of items I’ve ordered from Sparkfun over the years. Mostly for my own reference than anything else, and maybe not of much interest to others.

 Stepper Motor - 125 (200 steps/rev)  Stepper Motor - 68 (400 steps/rev)  Hook-up Wire - Red  Liquid Pump - 350GPH (12v)  Arduino Uno - R3 Nut - Nylon (4-40 Stackable 10-Pin Header AVR 8 Pin 10MHz 1K 4A/D - ATtiny13 10 segment LED gauge bar P-Channel MOSFET 60V 27A N-Channel MOSFET 60V 30A Jumper Wire - 0.1 4-pin Voltage Regulator - 5V Electrolytic Decoupling Capacitors - 100uF/25V JST Right-Angle Connector - Through-Hole 2-Pin JST Right Angle Connector 5 x Rectifier 1N4007 3 X Transistors - NPN 2N3904 3 X Transistors - PNP 2N3906  XT60 Connectors - Male/Female Pair JST RCY Connector - Male/Female Set (2-pin) Resistor Kit - 1/4W (500 total) RF Link Transmitter / 434 MHz RF Link Receiver / 434 MHz  BigTime Watch Kit  Capacitor Ceramic 22pF  Tweezers - Straight (ESD Safe)  Crystal 16MHz  Ceramic Resonator 16MHz  AVR 28 Pin 20MHz 32K 6A/D - ATMega328  ATmega328 with Arduino Optiboot (Uno)  STK500 Compatible USB Programmer  Miga NanoMuscle  Ribbon Cable - 6 wire (15ft)  PIR Motion Sensor  Stepper Motor with Cable  Hook-up Wire - Red  Light Pipe - Clear Core (6mm  Light Pipe - White Core (6mm  Light Pipe - White Core (3.5mm  I2C EEPROM - 256kbit  Heat Shrink Kit  Hook-up Wire - Yellow  Ribbon Cable - 10 wire (3ft)  Ribbon Cable - 6 wire (3ft)  Hemostats - Straight  Solder Wick #2 5ft. - Generic  6 Pin Right Angle Female Header  Hook-up Wire - Black  XBee Explorer Dongle  RFM22B-S2 RF Transceiver Breakout Board  RF Link Receiver - 4800bps (434MHz)  RF Link Transmitter - 434MHz  EasyDriver Stepper Motor Driver  Small Stepper Motor  Temperature Sensor - LM335A  IC Hook with Pigtail  555 Timer  XBee 1mW Chip Antenna - Series 1  Infrared Emitters and Detectors  Open Logic Sniffer - Probe Cable Kit  IC Hook to IC Hook Cables  IR Receiver Breakout DIP Sockets Solder Tail - 28-Pin 0.3 DIP Switch - 8 Position Hook-up Wire - White 74HC238 - 3 to 8 Line Decoder LED Display Driver (8-Digit) - MAX7219CNG Jumper Wire - Female to Female Connector 2x5 Pin IDC Ribbon Cable AVR Programming Cable Jumper Wire Kit Jumper Wires Premium 6 Button Pad 4x4 - LED Compatible LED Matrix - Serial Interface - Red/Green/Blue Arduino Mega Arduino Main Board Button Pad Controller SPI Super Bright LED - White - 1pcs Super Bright LED - Yellow - 1pcs Super Bright LED - Green - 1pcs Infrared LED - 950nm Triple Output LED RGB - Diffused - 100pcs Super Bright LED - Red - 1pcs Infrared LED - 850nm Super Bright LED - Blue - 1pcs XBee Explorer Regulated

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Sensors: Ultrasonic Range Finder

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In yet another shipment from Deal Extreme, I picked up a HC-SR04 Ultrasonic Range Finder. It seems to be a widely used and supported component, as there are plenty of posts around, and several supporting libraries for Arduino. Usage was also dead simple, and accuracy and responsiveness is good. One data sheet claims 2 – 500 cm ranging distance, at a 0.3 cm resolution, while another mentioned only 4 meters. The results I’ve gotten seems to be in line with that.

Following Jax’ post, and downloading the small ITead Studio library, it was up and running at once. The Arudino sketch is no more than init and read in a loop:
#include "Ultrasonic.h"
Ultrasonic ultrasonic(12,13);
void setup() {
void loop() {
  Serial.println(" cm");

The only problem I sometimes detected, is that it will not always handle a sudden change in distance very well. Or possibly not detect the echo signal if facing a distant surface at a slight angle. However, even so, I find that it fails gracefully. The Ranging function above will output a “out of bounds” number (around 2400 cm) when it cannot detect an echo. It means there is a very clear boundary between valid readings at 2 – 400 cm and “failure code” at ~2400.

The next step, is now to mount this on to the model helicopter I just got, and see what we can get from there. Initially as a separate and independent payload, I assume, but maybe later integrated with the main control board for the motors.

For completeness, I’m including the two functions in the library above. As mentioned, it’s simple, and just implementing the timing functions described in the above data sheet.

long Timing() {
  digitalWrite(Trig_pin, LOW); delayMicroseconds(2);
  digitalWrite(Trig_pin, HIGH); delayMicroseconds(10);
  digitalWrite(Trig_pin, LOW);
  long duration = pulseIn(Echo_pin, HIGH);
  return duration;
long Ranging(int cm) {
  long duration = Timing();
  if (cm) {
    return duration / 29 / 2;
  else {
    return duration / 74 / 2;

On a related note, there are plenty of range finders around, rated for different ranges and resolutions. Sparkfun has the Maxbotix ultrasonic line, as well as the commonly used Sharp IR Proximity sensors. The later are available in a wide range, from several retailers.

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Geeky watches

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Douglas Adams had something against digital watches, always criticizing the ape descendants for thinking they were neat. Well, I have to admit I rather like them. As a 8-year old, I spent the better part of a year saving up for my first Casio. However, at some point in the 90s, they seem to have goon out of fashion. Which is a shame, because there are some really nice geeky looking watches around now.

Take these from Sparkfun, for example: The “Solder : Time Watch Kit” to the left is, as the name suggests, a solder kit you put together yourself, to create a fun looking digital watch. Complete with resistors and ICs on display, which is a PIC microcontroller. To the left is the Arudino (ATMega328) based Sparkfun version; “BigTime Watch Kit“. Again you have to solder yourselves, but it is intended as a beginner’s kit, so everything are nice big through-hole components, which there are only a few of.

However, if DIY watches isn’t your cup of tea, you can always go for ThinkGeek’s selection. Here there is a lot of good looking geekery to choose from, including a DIP-switch controlled watch, a binary watch, or if you want to go simple maybe a sundial ring (possibly for the next steam punk gathering).

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Lego Panorama

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I’ve discussed panorama robots in the past, and here is a new creation. James Catan has created several Lego robots to do timelapse and and pan/tilt pictures. One of them were recently presented in Gadget Review, and shows holding a Canon Rebel XT with a kit lens. So not quite 5D, 200mm f2.8 as with Jeffrey Martin’s rig. Yet still a good and simple setup.

Another interesting pan & tilt product comes from Sparkfun. It is a robot arm, consisting of servos and and a claw. It will definitely not hold a SLR, but possibly some smaller pocket cameras or phones. As far as I understand, the complete robot arm comes in several parts which you’ll have to add to your order separately.

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We are the robots

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I’ve been looking up a few robots lately. There are a lot of impressive kits out there, and many of them pass as toys for kids, even if the technology included would have impressed researches 10 to 15 years ago. First out, the Pololu 3pi line following wheeled robot. It’s based on an ATmega328 chip, and can be programmed like an Arudino. It has five reflectance sensors to detect a line beneath its front, and two motors to control speed and direction. An Arudino library makes programming easy. It’s $100 from SparkFun.

Next, the Lego MindStorms NXT 2.0, a Humanoid with an impressive selection of sensors, including ultrasonic distance sensor, light, and colour. It is controlled by a 8-bit Renesas H8/300 micro controller, and can communicate over Bluetooth or USB. The programming environment is tailored towards kids, using a GUI box interface. However, most other major programming languages can also be used through third party compilers. As usual with Lego kits, the parts can be used to build other models as well. Instructions for four different robots are included, and your imagination is the limit to what other things you can build. At $280 from Amazon, this seems like very good value for money.

Over at Active Robots, they have several toys and kits, including the walking Penguin Robot, based on the  BASIC Stamp 2px24 micro controller. Although a bit clunky, it looks fun. And at £150, it sounds like a good intermediate kit.

However, on the high end, Active Robots stock the Hitec Robotics ROBONOVA-I. This looks like the king of hobby robots, with 16 servos controlling arms and legs. It’s based on the ATMEL ATMega 128 micro controller (aka Arduino Mega), with several optional sensor like “gyros, acceleration sensors, speech synthesis modules and operational devices such as Bluetooth controllers and R/C transmitters and receivers”. It comes at a stiff price though; at almost £600, or 700 Euros, it’s for serious hobbyists, and not Johnny’s xmas present. Make sure you check out the robot football game, and other corny moves on its home page.

Also have a look at Active Robots other robot links; plenty of interesting material to browser through.

Finally, I thought it would be appropriate to round of with Krafwerk’s 1978 classic, “The Robots” (original title in German; “Die Roboter”).  “We are the robots!

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Online Parts Suppliers

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Nathan Seidle, founder of SparkFun, recently told the story of how his business started from his bedroom in 2004. Since then, there has popped up a lot of good suppliers of electronics and other maker parts online. Here’s a short list of some of them. Feel free to send me more links. Since almost all of these are US based, sites from Europe is especially welcome.

SparkFun –

Very well equipped online electronics shop, with smooth ordering process. They stock basic components, soldering kits, robotics, Arduinos, and also produce several breakout boards and other items themselves. In Nate’s own words, “SparkFun makes technology more accessible.”

Furthermore, they have established healthy community, with comments and discussions on both the product pages and forums

Maker Shed –

Grown out of the MAKE Magazine, Maker Shed have lots of different “projects in a box”, or kits; a little bit of everything. Including electronics, crafts, and chemistry sets.

Solarbotics –

More components, kits, boards, and Arudinos. Focusing on robotic kists and solar cells.

The Electronic Goldmine –

Electronic Goldmine “specialize in purchasing inventory lots directly from manufacturers and companies that build electronic equipment”. A very good selection of basic components at good prices, however with changing inventory from week to week.

ServoCity –

Get your moving parts from ServoCity; including steppers, servos, DCs, and accessories. As well as other mechanical parts shaft couplers for your motors. Furthermore, they stock an extensive selection of batteries.

McMaster Carr –

McMaster Carr has a wast selection of mechanical and  electrical parts, as well as utility hardware.

Conrad Electronics –

Finally, the only non-US shop on the list for now; Conrad Electronics from Austria. They have web sites and shops in several European countries. They have a broad assortment of technical parts and kits, including consumer electronics, computer, hobby, lighting, and RC kits. Their selection of batteries is impressive.

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Motors and robotics

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Looking at the 12 V stepper motor at SparkFun, I came across a few other fun links. Including instructions for stepper motor wiring, a DIY surveillance camera, and an example project for the Arudino, using an EasyDriver Stepper Motor Driver. Also interesting, were the hardware suppliers: here’s some clamping shaft couplers from ServoCity, and lots more from McMaster-Carr.

Finally, I was eyeing up on of the robotics kits at SparkFun: “The POP-BOT is an Arduino compatible, mobile robotic platform. It comes complete with wheels, motors, sensors, software, documentation, etc. The POP-168’s pin-out is similar to the Arduino Stamp“.

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Controlling RGB Matrices with Arduino

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SparkFun just put a new tutorial on controlling their 8×8 RGB matrix with an Arduino. It includes a new library, so things should be easy to set up. Hopefully, I will be able to report back on my own project using this later.

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