Hammond Organ Sends Messages Which Can Be Decoded By A Spectrogram

hammond-organ-encodes-messages-spectrogram

Here’s an interesting use for an old organ. Let it get in on your Ham radio action. [Forrest Cook]  is showing off his project which uses a Hammond Organ to encode messages which can be displayed by a Spectrogram. We’ve seen this type of message encoding before (just not involving a musical instrument). It’s rather popular with Hams in the form of the fldigi program.

An Arduino was connected to the organ via a UNL2003 darlington array chip. This chip is driving some reed relays which make the organ connections to create the sine wave tones. With that hardware in place it’s a matter of formatting data to generate the target audio. [Forrest] wrote his own Arduino sketch which takes characters from the serial port (pushed over USB by the laptop), maps then to a stored 5×7 character font set, then drives the pins to produce the tones. As you can see in the clip after the break the resulting audio can be turned into quite readable text.

6 thoughts on “Hammond Organ Sends Messages Which Can Be Decoded By A Spectrogram

  1. A somewhat simpler approach that’s been in some tech column recently, there’s a keyboard design called “ASETNIOP” – it’s a chord-keyboard design for 10 fingers, only cares about which fingers are down, not where they are, so it can be used with data gloves or an iPad or a piano keyboard. So you could use the piano/organ keyboard to make sounds and the Arduino to decode them into text.

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