FEMU 1.0.4.ty.01005 (revision 1 of 2)

A project log for FEMU - An ESP32 Wi-Fi/Bluetooth board in TOMU form

Just for the sake of making it happen, I've designed an open-source TOMU form factor ESP32 design. It fits in a USB Type-A port.

femtoduinofemtoduino 08/13/2020 at 03:180 Comments

Hello everyone! Thanks to the overwhelming community support, this PCB revision is now being fabricated at PCBWay as of the time of this writing!

The RF antenna trace and wave guide has been revised to work with an SMD monopole chip antenna. The RF Trace impedance was too high in 1.0.3, so for 1.0.4, it has been redesigned to be 0.5mm wide, and have an impedance of 35ohm+10j (as per the ESP32-D2WD datasheet notes). A wave guide calculator has been used.

Once this order of FEMU 1.0.4.ty.01005 arrives, I'll need to test and match the RF design using a NanoVNA v2 (also thanks to community support!) while profiling the power usage with the JoulScope (thanks to JouleScope for lending me one for a bit!)

Stay tuned!