assembly.md

   1 # BOM
   2
   3 1x ATtiny4-TS
   4 1x 0806 100kΩ resistor
   5 1x 0806 200Ω resistor
   6 1x 0806 100nF capacitor
   7 1x CR927 lithium cell
   8 1x RCA/cinch style jack; 10mm inner diameter
   9 1x random paper staple
  10
  11 <!--
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  13 - "Luxury Soldering RCA Plug Jack Connector Speaker Audio"
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  18 Possible actual manufacturer:
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  20 - https://xinwotong.en.alibaba.com/
  21 -->
  22
  23 # Tools
  24
  25 - AVR programmer (e.g. [USBasp](https://fischl.de/usbasp/))
  26 - ZIF SOT23-6 socket
  27 - Soldering equipment
  28 - Side cutters
  29 - Kapton Tape
  30 - Abrasive paper, ~200 grit XXX/TODO: welche körnung?
  31
  32 # Software
  33
  34 `avr-gcc`, `avr-size` (optional), `avrdude`, `make`
  35
  36 # Assembly Instructions
  37
  38 1.  Insert MCU in ZIF socket and flash it using `make flash`.
  39     Note: the MCU requires 5V VCC for flashing!
  40     Note: to flash e.g. an ATtiny9, append `CHIP=9` to the command.
  41 2.  With the chip still in the socket and powered through the programmer, switch
  42     the supply voltage to 3v3 and attach an oscilloscope to the DEBUG pin.
  43 3.  Measure the frequency of the DEBUG signal and adjust the `CAL_MAGIC` value
  44     until it reads 8kHz.
  45 4.  Solder all components to the (flat) flex PCB.
  46 5.  Insulate the barrel/jacket side of the battery with a thin strip of kapton
  47     tape.
  48 6.  Bend the staple into a U-shaped clip.
  49     The clip shall be slid over the GND via between the MCU and C1.
  50     a) roll over on one end
  51     b) ca. 7mm down, bend 95°
  52     c) ca. 2.75mm down, bend another 95°
  53     d) flare open the ends and test/adjust fitment on PCB and battery
  54     e) cut off extra length on other end and roll it over
  55     f) place a kapton tape flag over the arm that sits on the component side
  56 7.  Twist together 8 strands of .1mm² enameled copper wire and cut off two ca.
  57     15mm pieces. Solder onto the PCB pads.
  58 8.  Cut down ground clip of the RCA jack; sand off both terminals until they are
  59     about 1.5mm proud off the surface.
  60 9.  Solder PCB to RCA jack; insulate component side with kapton tape.
  61 10. Push assembly text-side first deep into RCA jack housing. Test for shorts.
  62 11. Counter-rotate the RCA jack halfs about 3 times. This makes the wires
  63     untwist when screwing the halfs together.
  64 12. Fully close the RCA jack. Should take about 3.5 turns. Test for shorts and
  65     severing of the wires.