The Diavox telephone

Here is the disassembled diavox. I removed most of the PCB components before I left Sweden. Left the ones I will use such as the keypad matrix, R button, handset switch and screw terminals. The original cables were discarded and I found a good cable for the handset. The white plastic next to the bell ringer is a mechanical volume control for the bells.

Other hardware

• LiPo cells - 2 Lipo cells making 7000mAh.
• Olimex USB-gLink module - A 4G LTE modem module with a Quectel EG25-G.
• Antennas - Modem antenna and GPS antenna (will not use the GPS one).
• Pimeroni Pico LiPo - The brain of the project.
• 40 Volt SMPS PSU and H-Bridge boards - The mess I have to redesign.
• LiPo Shim - This was used to test the h-bridge and provide some protection.
• SLG46826 breakout board - Will be used to scan the keypad matrix.

I also have parts for breadboarding and other miscellaneous stuff.

Other hardware I need to accquire

• Logic level shifters to interface the pico with the modem module.
• Another Pico for SWO debugging.
• NAU8814YG codec board - This board I have to design myself which is an other opportunity to learn something new.