This is an interface hat for a DigiPi by KM6LYW (www.digipi.org). I am releasing fabrication files under open source license so anyone can order PCB's with SMD mounted components. Feel free resuing materials as you wish, if someone decides to produce PCB's for commerical use, I am fine with that too and have no objection.
Schematic is based on KM6LYW's original documentation at www.digpi.org. PCB was designed to utilize the SMD resistors and MOSFET to fit under the tight Pi Zero configuration and be flush with the display hat.
These are the additional THT components to be sourced for the final assembly:
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2.54mm Double Row Female Long Pin 11mm Breakaway PCB Board Pin Header Connector https://a.co/d/0CLkeeG
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TRRS Connector https://a.co/d/cTMyE9t
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LED's https://a.co/d/4QbojtL
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JST-XH 3-pin Male-Female pair https://a.co/d/czNhTzQ or JST-PH 3-pin pair: https://a.co/d/5Sgg32F
- Use fabrication files in DigiHat_Fabrication_Files folder to order the PCB from PCB manufacturers like JLCPCB. If you chose SMD factory assembly, chose bottom-side assembly! And verify component placement. I had to flip the MOSFET position. The PCB will arrive with resistors and the MOSFET soldered. Optionally, you can order PCB front panel as well, which will give your DigiPi professional look. There are two versions of the front panel - with holes for LED's and without.
- Solther PIN header and TRRS connector to the bottom of the PCB.
- Sother LED's at the top, pay attention to the polarity. The negative pin (short pin, the cathode) goes to the square pad.
- If using JST-XH connector - bend JST male pins 90 degree and solder to the bottom of the PCB as shown in the photo below. If using JST-PH connector - it has a smaller height but almost same distance between pins, no bending is necessary.
The TRRS pins have been chosen such a way that hat is compatible with DigiRig cables. So far, successful tests were made with:
- (tr)USDX audio/PTT cable: https://digirig.net/product/usdx-cable-for-digirig-mobile/
- Baofeng audio cable: https://digirig.net/product/baofeng-cords-kit-for-digirig-mobile/
Enclosure 3D models are at thingiverse: https://www.thingiverse.com/thing:6478217. Includes matched 3D-printable front panels as well as an alternatice to PCB-version of front panels.