This is [S]impleAVR’s entry into the November 2010 Project of the Month contest. The RFM12B is an ISM band FSK transceiver radio operating in the 915Mhzband. The project uses the MSP430’s ADC to capture the radio’s reception strength through the Analog Signal Strength Indicator(ARSSI).

The frequency and signal strengths are packeted and then sent to a host application through the UART for visualization. The host application is written in Perl. Although the radio module that [S]impleAVR used was tuned to the 915Mhz frequency, he was able to get signal strengths from the 433Mhz ans 868Mhz bands too.

The Specktrum Analyzer has the following features:

  • High resolution w/ analog ARSSI reads
  • Adequate speed to show FHSS activities
  • “915Mhz” RFM12B module used, can also set at 433Mhz, 868Mhz with less optimal results
  • “amplify” setting (software) to visualize weak signals
  • “sweep” setting to accumulate and average over time, used to analyze intermittent signals (digital, RHSS, etc)
  • “zoom” to zoom in part of the capturing spectrum
  • “peak” and peak hold function in gui for better visual and signal comparison

Check out his video below that will make you go “Woah dude…”

Code and schematics can be found in his forum thread or on his blog page. Thanks for submitting your project [S]impleAVR. Make sure to leave your “whoas!” below