Zach Peters Homepage

A collection of projects, random musings and handy information

Hardware Projects

  1. Bluetooth Radio
  2. Folder Cam
  3. Morse Code Glove

Bluetooth Radio (2017)

In 2017, a good friend was moving from away so we wanted to give her a going-away/ housewarming gift for her new place. She always had a flair for mid-century modern so we decided that something with that style would be the perfect gift

After some searching around, we found the perfect thing. It was an older clock radio, that had just enough mid-century feel. Now to make it special.

outside view of an old radio

After searching online, i found a few components to start the transformation. Most of the "brains" of this project was the TDA7492P 50W+50W CSR8635 Bluetooth 4.0 Audio Receiver Digital Amplifier Board. I'm not sure if this particular model is available but there are dozens of similar boards of similar specs. This should cost you around $20.00

another view of the bluetooth module

Construction was relatively simple, my skills are sorely lacking and it maybe took an hour to throw everything together. I disconnected the original power plug from the transformer so that was no longer in use. Then i routed the power plug from the ac adaptor that came with the bluetooth unit out the back. Ideally, I wouldn't want the body of the ac adaptor inside the radio housing, but it is probably safer and produces less heat than the original transformer.

the guts and wires of an old radio

The last piece i needed to figure out was essentially converting a stereo signal to mono. It would seem that you can just hook both left and right channels to the "positive" on the speaker and you'd good to go. Unfortunately, this is not the case. You will notice some of the sound comes through but everything sounds distorted. This is due to the fact that the speaker is trying to reproduce two different signals at the same time.

rear view of a speaker

Thankfully, this is easy to remedy. With a voltage divider you can sum the signal, producing a mixed signal. I never ended up writing down the exact components and specifications that I used but you should be able to come up with something by looking up a basic circuit and experimenting with different values.

As you can see the finished build looks more or less the same as the original. The other addition was connecting the top button to the pairing circuit of the bluetooth board. I could never figure out its original function but it worked beautifully for my purposes

top view of a radio

Folder Cam (2015)

Coming Soon

Morse Code Glove (2016)

Coming Soon


Part Description Cost URL
Elastic band Just something simple to mount the board on $10
Glove The cheapest conductive glove i could find at Walmart $3.95
Conductive Thread You'll need a decently sturdy needle for this. $8.00
Jumper Wires Easy way to connect things for experimenting $5.00
Headers Makes it easy to remove the teensy when you are done tinkering $5.00
Perfboard Really easy way to mount your projects $8.50
Teensy The best "arduino like" out there $20.00
Total ~ $60

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