Simple heterodyne detector

This one is still under construction! (First set of board had just been ordered)

 

Last year I buit heterodyne detectors with the kids at school. This was a lot of fun, but like with al starters projects we are missing a proper frequency readout.

I made some frequency counter using a project I found on the internet but is was quite complex to build, so I made myself a new circuitboard so all can be mounted as SMT parts in a modern factory. Most parts are mounted already, only a switch and some and wires for battery, microphones and speaker need to be soldered as wel as the tiny LED display.

The TeensyBat detector is quite complex "expensive" and more for the advanced user. I hope these simple heterodyne detectors can be the starters detector. Still quite useful but much quicker to build and less money involved. (And less money wasted if you turn out to be bad at soldering)

 

Below you can see the new circuit board plans.

The design is based on the Batlistener IV by Laurens Wolfden

And the counter is based on "simpelest frequency meter with avr" by Danyk

 

 

 

The enclosure is 103x63x26  which makes it a nice compact unit, on the new design we also have an extra ultrasonic transducer (for lower frequencies) the first ones only had 40kHz transducer and there also is a headphone connector. (This headpone connector probably is not in the most convenient place but as you can see the board gets a bit crowded.