John,
It took me some time but I have put your MP3 Sound Card to work in a project that I've had sitting around for some time. Nothing sophisticated as far as the sound card goes. I’m simply using the four button keyfob to trigger sounds. Perhaps when your speed sensor card is available I might try working that in.
I installed your card in a Lionel Scale Polar Express Baggage Car. In order to get the largest speakers I could into the car, I had to make some severe modifications to the car body and frame. I won’t show you pictures of that part as I am not proud of my abilities as a metal fabricator or model builder (some might call me a "butcher"). Suffice it to say that I had to remove the movable doors and make them permanent and cut two big holes in the frame. I also did not reinstall the On-Off switch. That will be a future effort. Also, I need to find a way to blur the door windows so folks can’t just see the speakers and wires inside.
I used two 4 ohm, 3 Watt speakers wired in series. They just barely fit in the frame. I had to keep the plastic interior just to add some extra strength to the weakened frame. It seems solid however. Not vibrations that I can detect.
Everything is very roughly wired, using Wago connectors and some solder connections. The board is velcroed to the frame so I can remove it to tinker further.
The sound you hear in the video is recorded directly from the car on my iPhone 12 Pro Max. I prepped the audio using Audacity, mixing the original stereo source to a mono file and tinkering with compression and equalization to make the audio sound as good as it is. I think more tweaking might yield further improvements. The volume is set loud so that the car can be heard over running trains. That makes it sound quite loud in a quiet room. (I have edited the video to reduce the volume)
No problems whatsoever other than me mangling one of the jumpers which caused a lost connection; easily fixed. Just a word of caution, don't squeeze the jumpers too tightly with your needlenose.
When you have production quantities of the boards, please let me know.
Thank you for this board. Works like dream. Can't wait for your next products (RF switcher, Speed Sensor). Great work.
Video of the Scale Polar Express Sound Baggage Car. YouTube Link.
