RFD22301 (RFduino) breakout

I’ve been doing some projects with the RFD22301, also known as RFduino and therefore decided to make a breakout for it. It’s also the radio used on the OpenBCI v3 system for data transfer, communication and programming. This breakout board can also be used as an OpenBCI dongle and can be plugged directly on this CP2102-based USB to TTL UART converter. Of course any other converter will do as long as it has 3.3V logic level. Watch out for that!



The jumper sets the DTR pin of the USB to serial converter to either the reset of the RFduino or its GPIO6. If it’s on “reset”, the RFduino itself is programmed during code upload. On the other position it starts programming the microcontroller on the OpenBCI board, assuming the OpenBCI firmware is flashed on the RFduinos of both the “Host” and the “Device” side.

Eagle files:

Arduino Pro Mini – nRF24l01+ 1.27mm adapter

The Atmega328P and nRF24l01+ combo is also a quite common thing to use over and over again in wireless sensor nodes, remote controls and so on.
I’ve chosen to make an adapter for the Arduino Pro Mini (the 3.3V version) to be able to piggyback small SMD versions of the nRF24l01+ with 1.27mm pad pitch on it. This way you have a tiny board sandwich which is not much bigger than the Pro Mini without the need of wiring everything up over and over again.



A quite uncommon soldering technique is required to connect the adapter and the pro mini: align the holes of the pads of the Pro Mini and the adapter and after heating up the top pad, let the solder reflow to the bottom pad through the top pad. Of course you can solder headers as well. There is room on the board for a 0805 capacitor (0.1µF-10µF are sometimes used to prevent power issues while transmitting). The VCC and GND as well as the optional IRQ pins of the radio are broken out on solder pads and have to be wired manually, since I didn’t want to make the adapter too big and still leave some flexibility.

Eagle files:

Attiny85 SMD breakout

I’m using the Attiny85 quite a lot, especially since it’s programmable via the Arduino IDE. I like programming the AVR chips over an ISP programmer (USBtinyISP or USBASP). That way there’s no need for messing around with bootloaders.

After building a pogo pin adapter for the standard Atmel 6-pin ICSP header I needed a handy and tiny breakout board for some chips because I was tired of building the same circuit again and again and so this project was born. It contains all the essentials to be able to handle the Attiny85 in a SOIC-8 package conveniantly, such as reset pullup resistor, decoupling capacitors and an LED on PB0 (PWM pin). It’s tiny and can be left in small projects or used on a breadboard.



The eagle files can be found here: