Neat little beacon using an 8 pin Atmel AVR…

April 28, 2013 | Amateur Radio | By: Mark VandeWettering

Previously, I have read about a wireless Morse thermometer designed by Steve Weber, KD1JV. I played around with the basic idea in a YouTube video I made. It basically powers a little Colpitts oscillator from an IO pin on an Arduino. Weber’s circuit did much the same, just using a small 8 pin AVR and a temperature sensor to send the current temperature via Morse code.

Over on the Open Emitter blog (sorry, don’t know whose blog this is) there is a twist on this basic idea: instead of using a separate oscillator, use the oscillator that drives the microcontroller as the emitter (probably of just a few microwatts into a short wire antenna). To on-off key the oscillator, the Atmel chip is put into power-down mode, and woken up via the watch dog timer. I think it’s a cool idea, and worthy of experimentation. I’ve got some ATTINY85 chips on sale (just $1.10 each) which will probably be breadboarded into a test circuit, using either some of my 10.140Mhz crystals or maybe some of the 80m or 20m crystals that I have lying around.

Check out the article:

Tiny Beacon


Comment from MikeK
Time 5/5/2013 at 9:43 am

Mark, you’re a ham, so here’s something I thought you might be interested in. I just found out that Maxim makes a 45MHz-650MHz VCO, the MAX2606. Mouser has it for only $2 and it doesn’t need a crystal. Not your HF style, but might be worth playing with.

Comment from
Time 6/11/2013 at 4:37 pm

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