This describes how to build these boards.


SHOPPING LIST

Components - see components subfolder
Also get a socket for the ATtiny, you don't really want to solder it in place
Wire for the little coil - see specs in components file 
PCBs - render with Eagle and order for ~ $5 from Seeed Studio
ATtiny programmer - see https://www.sparkfun.com/products/11801

Notes:
* Must be the 20Mhz version of the ATtiny. Still not really guaranteed to work, as we are overclocking to 32MHz but haven't seen any
  issues.
* The little coil must be the right wire diameter, number of turns, coil diameter. You're likely to overshoot the 96MHz frequency printed
  on the board. Press the coil together to reduce the frequency until you're at 96MHz.
* The battery must be the rechargeable LIR2032 type. The usual non-rechargeable CB2032 doesn't have enough wattage.


HOW TO MAKE

1. Open project in Eagle.
2. Follow tutorial on Seeed studio for their most basic cards (they have a prototype program for around $5 for 10 cards), and order the
   cards.
3. Buy the components and the rest from shopping list above.
4. Make a coil by turning wire around a screwdriver of the right size. Look at the photo.
5. Solder everything.
6. Program the included synth.hex to your ATtiny as described below. Set fuses then upload build.
7. Insert LIR2032 battery and turn the unit on, LED should light up. After 3 minutes when the song is over it should blink.
8. Search for the signal on your rado. Press the coil together until you hit 96 MHz.


PROGRAM

Hoe to program the ATtiny using avrdude and usbtiny programmer

# Set fuses to defaults (not required)
avrdude -c usbtiny -p attiny85 -U lfuse:w:0x62:m -U hfuse:w:0xdf:m -U efuse:w:0xff:m

# Set 16mhz clock and other required fuses
avrdude -c usbtiny -p attiny85 -U lfuse:w:0xe1:m -U hfuse:w:0xdf:m -U efuse:w:0xff:m

# Upload binary
avrdude -c usbtiny -p attiny85 -U flash:w:synth.hex



CONTACT

spookysys at gmail