I have built a PCB which uses an ATMEGA328-p standalone chip (no Arduino board). There's a connector on the PCB to program it from a nano with the ISP sketch on it. This works like a charm! However I want to built de nano module into a programmer. What I want to do is have an SD-card on the programmer which has a compiled hex file on it. Then I can hook this programmer up to the PCB and program it.
The whole idea is that this programmer runs on batteries and does not need an external power source and does not require a computer to program the arduino.
Theoretically, this idea sounds really nice in my head. However I am not sure if loading code onto the chip like that, from the SD-card, is even possible. Has anyone of you attempted this before or has some experience?