I added a 6 pin port on the RFM2Pi board that can be used for a number of applications. The port has GND, D3, D7, D6 and VCC routed, and by no coincidence matches perfectly the pinout of the Digole 0.96″ OLED Serial display that I toyed with previously. The OLED PCB is exactly the same size as the RFM2Pi board, and since I use the flat crystal version of the RFM12B radio module, the two can be “sandwiched” together:
I added some basic test functionality to the firmware, it displays the current configuration and the last packet source, RSSI and ACK status. RSSI is calculated using @tht’s method as per this post. The code can easily be extended to visualise emonTX power readings for example. The updated PCB layout is on github.
Hey – i just made my PCB board and I have a problem programming atmega328p – I have used information from here:
http://wiki.openenergymonitor.org/index.php?title=RFM12Pi_V2
So I did:
sudo avrdude -v -p atmega328p -c usbasp -e -Ulock:w:0x3F:m -Uefuse:w:0x05:m -Uhfuse:w:0xDE:m -Ulfuse:w:0xE2:m
First try looked OK – but verification fails and AVR seems not to be seen by my programmer:
Device signature = 0x000000
I expect this has something do to with lock bit?
Not sure.. looks good to me. I use USBTiny programmer and the only time I have seen error like that is when the pins didn’t make good contact.
So I have 3 of those where only one is OK (I think as LED is on for a few seconds after it gets powered). I’ll try to see if maybe bootloader is OK and I might be able to push some .hex via the serial of RPi.
Another question – why are all SMD elements so small? 😉 0603 is hard to get for DIY as mostly you have to buy huge quantities (like 100 or more). Longer pads would be better so one can use 0603 others can go for 1210 that is way easier to find. I think there is enough space for longer pads.
This particular board was made to be small hence the SMDs.. the V1 of the board is trough hole and much more friendly to DIY: http://harizanov.com/wiki/wiki-home/rfm2pi-board/