Recently, I got my hands on four pieces of dirt-cheap radio modules – the nrf24L01s or the Nerfors as I like to call them. After watching them rot on my table for a while (they unfortunately don’t rot away like the fruits), I finally decided to do something about them. And not to mention a dear old friend who never misses a chance to say “Dude, just f@#king finish something!”.

So here is what I am going to do. I am going to bring these Nerfors online. Then I am going to get three of these Nerfors (the Leaf node devices) to communicate with my raspberry pi (the Gateway node device). Then I am going to get my raspberry pi to host a web server that will allow me to talk to each of the leaf nodes and receive status updates from them over a HTML5 page. Then I am going to give some work to the leaf nodes (rather than just let them send “oinks”). I have a couple of temperature probes lying around. I have a couple of servos lying around. Plenty of work for the nodes.

But the real work will be to control the brightness of an LED lamp. I will talk about this little project of mine soon. Like any other unfinished project of mine, it is waiting for the trainman to come and pick it up. Some of them have been waiting for a long long time.

Here are some technical details about the Nerfors.

The connections are as follows:

• GND – Arduino GND pin
• VCC – Arduino 3.3V pin
• CE – Arduino digital pin 9
• CEN – Arduino digital pin 10
• CLK – Arduino digital pin 13
• MOSI – Arduino digital pin 11
• MISO – Arduino digital pin 12

You will notice there is a capacitor connected across the VCC and GND pins of the radio module. This capacitor is needed to allow the radio module to pull current more efficiently from the Arduino. This is necessary when the module is transmitting, as there are very short duration current spikes during transmission that the Arduino cannot handle very well. The capacitor stores the current and discharges whenever the module needs more current.

Here is the video of two nerfors talking to each other: