Arduino Radio Spectrum Analyzer prototype on a breadboard

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I am building a Radio Spectrum Analyzer which measures signal strenght in the 2.4GHz band, using a CYWM6935 module and Atmega 328 MCU. I want to set it up in several steps:

Atmega328 on a breadboard

There are quite a few good "Arduino on a breadboard" tutorials out there. I suggest you take a look at

These were the components I bought (or borrowerd here on the nurdpspace):

I will discribe the breadboard setup bit-by-bit. This is work in progress.

Arduino breadboard1.jpg Switch.jpg Arduino breadboard2.jpg Arduino breadboard3.jpg Arduino breadboard4.jpg

Connecting the CYWM6935

To connect the CYWM6935 module to the breadboard, I created my own cable. I found a 2.5" Harddisk adaptor plug, which fortunately has pins on one side with the spacing for my flat cables like floppydisk cables, and on the other side has holes with a smaller spacing, exactly the size of the CYWM6935. Using this plug, a flatdable, some simple PCB and a few jumpers, I soldered something together that allowed me to connect the radio module to the breadboard.

I split a floppy cable that was lying around, so it had 10 wires left. On one side I left the connector in place. On the other side I cut off the connector and stripped the wires. I soldered each of these free wires to a PCB. On each of the lanes for these wires, a jumper pin was soldered, so I ended up with a 10-pin connector which fits the breadboard. There is one thing you should know about this connection (and could be done better). If you connect the wires this was, the order of the pins on the breadboard correspond to the CYWM6935 pins in a weird order. Their order is: 2,1,4,3,6,5,8,7,10,9. If you want the pins on the breadboard side, to correspond to the CYWMUSB6935 module in the correct order, you should twist around each pair of wires. This is how the cable looks now.

Cywm6935 connector cable.jpg

Connecting this plug to it, you can plug in the CYWM6935 module directly.

Connector cable with cywm6935.jpg

Programming the Atmega328

Creating desktop software for visualization

I chose to create a Java GUI using JFreeChart to read the data from the Arduino using an FTDI cable on a serial port (or actually USB) and visualize that in the GUI. The program can be found on Github.

This is a screenshot from the app. It allows you to reset the maxima by clicking the button.

Arsa screenshot.png

Assemble everything on a custom PCB