Using RUMlogNG for iOS with an Elecraft KX2 over Bluetooth [Part 2]


I finally found some spare time today; the weather was not so good outside, and I’m on vacation this week… that’s help a lot! 🙂 My main objective today was to build a functional prototype, a proof of concept.

Step 1 : Install and power the Bluetooth module on a breadboard using a small 5V power breadboard supply.

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Step 2 : First I used my logic analyzer probe with the software Logic from Saleae on MacOS to verify if all communication parameters were well set. Hooray! I transmitted the word “TEST” between the iPad Adafruit app running on the iPad Pro and the Bluetooth module.

Then I established a link between the Bluetooth module and RUMlogNG To Go iOS app running on my iPad Pro. The Bluetooth module needed to be recognized first before going further.


Step 3 : Another step was to install a MAX322 chip needed to «translate» the information using the RS-232 protocol between the Bluetooth module and the Elecraft KX2. Note the MAX322 must be powered at 3.3V. The Bluetooth module can provide such voltage output. But for this prototype, I  powered the chip using a 3.3V voltage line from the breadboard power supply.

Step 4 : Every components are now properly hookup. RUMlogNG To Go iOS app on the iPad Pro and the Elecraft KX2 are ready to establish a link. Note the baud rate must be set properly on the transceiver at 9600 bauds. As you can see in the picture below, I entered the CAT command IF; and the KX2 returned me the frequency on VFO A 14.210.


There is a short video below I captured from my iPad Pro with the Elecraft KX2 and RUMlogNG To Go controlled by the Bluetooth interface in action!

Note that I captured the initial footage with the new capture function available in iOS 11. Then I completely edited the video and did all effects with my iPad Pro using the iOS LumaFusion. A great app!

My goal still to build the project for under 35$ USD. I’m also planning to design my own PCB board and offer it as a kit; Fritzing is already running on my Macbook Pro.

More to come in my next post!

Meanwhile, do not forget to follow me on Twitter @VA2SS, and subscribe to my blog and my YouTube channel as well.

Have fun and stay tuned!


de Jeff | VA2SS