A lot of time is spent in the kitchen, but until recently I didn't have a great way to listen to music in there. I'd play songs on my cell phone, but the phone's tiny speaker isn't loud enough to compete with the noise of cooking dinner and washing dishes. I wanted a bluetooth speaker, but rather than buy one I made my own from an old PA speaker purchased at a thrift store. It's far from perfect, but it was a fun (and sometimes frustrating) project and it's unique.
The heart of this project is an old RadioShack speaker, catalog #40-219. It's an 8", 8Ω speaker I paid $8 for at a thrift store. Being an old PA speaker, it's certainly not an audiophile's dream, but I was surprised to find it actually didn't sound too bad. It's good enough for playing music while working in the kitchen.
Above my stove, there is a recessed outlet in the wall. It seems to be original to my 1950's home. I'm not sure what it's for, maybe a clock? I mounted the speaker here since power was readily available.
Amplification comes from a Velleman K4001 7w Mono Amplifier kit. This is a cheap & easy to build amp kit that provides plenty of power to drive this speaker. I built mine with upgraded caps. I don't really think it was worth it, but I already had the caps which were leftover from another project. The amp is powered by a Mean Well RS-15-15 power supply.
The bluetooth receiver is a TinySine Bluetooth Audio Receiver board. Power comes from an old cell phone charger. It's a bit of a hack, but I have lots of spare USB chargers laying around so it made sense to use what I had. There is a 50kΩ pot between the receiver and the amp for volume control. I've found that I have to keep it set very low.
Here is the finished build. I admit it's a mess. I don't like the layout and there are occasional issues with the signal dropping off, despite the fact that the phone I use to play audio is very close by. I suspect the bluetooth receiver is too close to the mains power, leading to interference, or maybe it's just not positioned well. It might have been better to mount it towards the bottom of the enclosure, since the phone is below. The power switch should also be lower - thankfully, my wife and I are both tall. :-)
Despite the issues, it works well most of the time and me and my wife use it frequently to stream music and podcasts from an old cell phone we keep in the kitchen. Someday I hope to take another shot at either changing this speaker or building a new one with some improvements.
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Posted 1/17/2019