Disco Bike - Radio test

This is a test of a cheap 433Mhz transmitter and reciever from SparkFun electronics. Together they cost only $7 for the pair. I did a test with two arduinos one transmitting data and the other recieving, both outputing over serial to debug. The fidelity seemed pretty good (Although it was only short range ~1m) without an antenna. This video shows a test using the musical output of the computer which is sent to an anolog pin on the arduino. The Arduino reads the voltage and sends a byte to the transmitter. The receiver on the other end then pulls that value in and is SUPPOSED to adjust the brightness of the LEDs accordingly.

Unfortunately, the signal is two noises causing the value to fluctuate wildly. The instability also means that the LEDs are on for a very short period so its difficult to see the lights change their state.




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PCB Fabrication

A pcb made with a router at the Santiago MakerSpace

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Embedded Bike Lights + ATTiny = More Flashiness

I have been slowly working towards a mobile bike light show. The most recent step in that project has been to create a small PCB that I can place inside the wheel with an MCU that will be able to control the flashing of the lights.

I have already done several prototypes of such a board. Here is video of the different modes I have programmed in. Sorry that LEDs dont glow very brightly. I was VERY conservative with the current limiting resistor because I didn't want to risk blowing any (they would be a pain to replace). The power supply is putting out around 200mA but it could be closer to 400mA.

Fundamentals of EE on Coursera

So frustrating!

Arduino Shield - Stepper Driver and Digital Caliper Reader ver.3

This is my 3rd full revision of a board I am making for another project. I thought I should post the schematic/layout incase anyone else finds it useful. I am getting faster at this layout stuff. The first was so painful but I am starting to get the strategy down.

The board uses an H bridge to drive a small stepper motor. The power for the stepper is fed of the Vin pin of the arduino. So to run this you will need a 9-12v power supply feeding into the Arduino barrel jack. I have made capacity for two calipers (To measure X and Y simultaneously).

Design is based on the schematic at http://arduino.cc/en/Reference/StepperBipolarCircuit and the Nerd kit DRO tutorial. http://www.nerdkits.com/videos/digital_calipers_dro/

Check out those sites for backround reading and code.

Check back here later for build photos and my code.

Check back here much later to see the circuit in a useful application.

https://docs.google.com/file/d/0B8_hXvCtBTMMUXVFQWN4RkVTQkE/edit

Ada Fruit breadboard power supply

My package finally arrived from adafruit. The first thin I did was build up the breadboard power supply the breadboard in a little project box I have with an arduino. I plan to wire it up so the power supply will power the board when connected or, when using lower currents the board will run of the USB without powering the electronics on the supply circuit.

Any suggestions on how to do this without too much voltage drop??

A couple of negative things I would like to point out are: 

• There are no holes in the PCB for mounting the device in a housing.
• The heatsink is not well suited to the circuit layout because it clashes with the voltage regulator and screw terminals.