mRF24J40MA 2.4GHz Transceiver USB Base Station Project
Like many of us, I've been working quietly on my next robotics project. Along the way I wanted to be able to wirelessly monitor what's happening deep inside their firmware. On the bench a USB cable is enough but once they begin to free roam under their own control a wireless solution is needed.
I bought some MicroChip mRF24J40MA 2.4GHz transceiver modules for about $12 from DigiKey. They communicate with the processor via SPI. I managed to interface the boards to my robots, Fitzy and Carraldo, and after many tribulations they could chat back and forth.
At this point my plans for extending the conversation to my PC slammed into a wall. Microchip sells a USB attached network sniffer for about $50; the ZENA. I had hoped that I'd find a way to tap into this device. Unfortunately it was beyond me. So, in the end, I build my own USB dongle equipped with a mRF24J40MA and so now I can listen in or communicate with my creations.
I've shared the design on the linked page; all code, schematics, toner transfer patterns, and build instructions. Perhaps someone will find it, or bits of it, useful.
In the meantime, I'm working on a remote wireless card that will sport a virtual 8 bit port plus a small prototyping area that you'll be able to control from the wireless USB dongle. The hardware is complete and I'm writing the code. It's largely adapted from code I used in the robots and the USB dongle. It will support regular digital input and output, 12-bit analog input on 4 of the pins, PWM, Servo functions and hopefully a host of additional features.