When researching the amp to power the car’s (probable) 30w speakers I kept coming across amps with bluetooth built in and then it hit me:
I was over engineering things, I didn’t need ESP32 involved at all!
What I needed was something more basic like this:
This is the Dolla Tek 2x50w TPA3116 Bluetooth 5.0 mini amp.
This simplifies things somewhat.
I should be able to connect this directly to the car’s audio red power wire* (ignition), though I may need a fuse.
(*There is also a constant yellow wire from the battery but this then gets complex as you don’t want to accidentally drain the battery. I can live with the constraint for now that this only works when the car is started, if that becomes a pain, I’ll revisit options).
There is one volume knob which doubles as an on/off switch. That fits well with the minimal design I had in mind.
I doubt that I can change the name of the Bluetooth device but that’s fine, doesn’t bother me. It would be fun if you could but it’s no show stopper.
Aside: when I had a Bluetooth speaker (powered by it’s own internal battery) in the car, it would occassionaly, whilst driving, have bad interference for a few seconds before audio resumed. I never got to the bottom of this (well, I didn’t look very hard!). This is just something for me to remember, if there IS similar interference when I run this new amp, then at least I know it’s not the device itself, there is some other environmental/geographic factor at play. Anyway, that’s a ‘tomorrow problem’.
Whilst this simplifies things (and it is a shame not to use the ESP32 but there is no need, that’ll be used in a future project) it does leave a really interesting bit that I’m keen to learn about: I’ll still need to house/mount the amp et al and, better still, will need to 3D print a dashboard fascia. That’ll be interesting designing that, keeping it simple, giving space to just that one knob etc (perhaps even change the knob):
Is the knob central? Or does it look more intriguing being (say) bottom left? My gut feel is that exact centre feels weird.
I’m not going to buy a 3D printer yet, I’ll use an online service.
I’m not an audiophile and the car’s speakers are pretty crappy so just having semi decent streaming will be great (and before you say “if that’s the case, just use the phone’s loudspeaker“, nah, that’s crappy, have tried that, can’t live with that).
Steps
Ok, let’s revisit the steps:
- Buy the amp
- Perform a basic lab test to check it works
(ideally with a similar speaker to what’s in the car) - Get the bits I need to connect to the car’s custom audio ribbon.
- Create a test connecting device to the ribbon (and perhaps with a fuse as well, as ChatGPT is telling me)
- Drive around a bit with it playing (see if I get that occasional interference). If I hit a problem, will need to research.
- Consider how to mount (e.g. gut old stereo to keep cage & then mount a 3D printed fascia to the front)
- Design the fascia, get printed etc (rinse and repeat if mistakes/iterations)
- Mount & enjoy (to so speak)