Some people on HaD asked me about schematics and PCBs because they want to build their own PDA. I don‘t really have a nice schematics and my current hardware has many shortcomings. Also much of the case is made out of hot glue and that’s not ideal.
Now I will mainly focus on new hardware revision (PCBs and case). My main goal is to design open-source hardware PDA. The current software stack will be replaced with something else in the future.
What will be improved or added:
- It will be possible to replicate easily
- SD card will be connected over SDIO instead of SPI
- Modular design will enable use of different LCD modules.
- PWM enabled LCD backlight
- I will replace MCU with something bigger (100 pin instead of 64 pin) to get more pins.
- 3.5 jack for possible mp3 playback
- Device will be powered from out of the shelf phone battery (some easy to get nokia or samsung one).
- There will be better buttons.
- Under-voltage protection and overall improved power circuitry.
- FTDI for better connectivity
Now I am looking for suitable displays and batteries (mainly their connectors). I will order the parts, draw schematics and make sure it works. Then I will release schematics and move to design of the
improved case. Two fellow hackaday users offered me to make the PCB layout so that‘s covered. There definitely will be few iterations of hardware design before it will be done.
I will keep you updated on my progress.