This project has been on hold for over a year so I could deal with life stuff. I'm getting back on track.
It's time for a new module. I'm upgrading to the nrf52 series which should fix RAM usage, allow me to use an updated SoftDevice, and possibly use mbed OS 5.
I bought a cheap Chinese nRF52832 module similar to my nrf51822 so that I can hand solder it. If the pinout is reasonably close I'll transplant it onto my existing perfboard prototype.
Planning ahead for production, I found the Fanstel BM832 (nRF52832, 64KB RAM) and the reduced-cost BM832a (nRF52810, 24KB RAM). We'll see if I can keep the RAM under 24KB but it's not a priority. These modules are already FCC certified so I won't have to foot that bill if I ever sell these. The modules are BGA so I'd have to set up a reflow oven.
In other news, I'm attempting a USB-C version! This idea has been on the backburner for a while but there's a flex PCB contest going on right now. Using a flex PCB will allow the controller to reshape for multiple phone sizes - a key feature of this project. The deadline is fast approaching so hopefully I can crank it out and win a prototype.
I've made a new project page for the USB-C version. More updates to come so hit that Follow button.