Based on our previous experience with our first MORPH-ESP240 crowdsupply.com campaign, we wantedf to make a small device capable of behaving as a USB Keyboard or USB Key. So we decided to remove all the unnecessary components and build a minimalistic USB device. The PCB software used is KICAD.
The cost to build one item is evaluated to : 13 USD for the components. The PCB is 4 USD. You can get the PCB here on tindie.
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You can remove D1 and R3 SMD components if you to not need any light which may be anoying if you want to watch the display.
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The soldering is not a particularly difficult operation. You can do it using a basic soldering iron . No oven or heat place is necessary although it can be easier and faster.
Where's the source code?