I'll include a link to this on eBay , these are SD card or flash drive decoders to audio , it has an audio output through the phono jack , but it also plays one channel , through a built in amp , you can run it through a little amp board , or if you want it to play a sound effect , you can also use that output ,and record your audio in mono. It runs on 5 volts , which is USB voltage , it's got a USB jack, but it's provided with two solder lugs , for direct wiring power . If you use an MP3 file , it'll auto play ,as soon as power is applied . You can set a repeat for a single mp3 file , or all mp3 files on the drive . It seems to be non volatile memory , so it remembers that setting . The only minor issue I found , is they don't like cheap lower classes of SD cards , they don't like ONN (Walmart) cards at all. And the cards have to be under 16 gig , or it messes with playing the card . Other that , it's worked great in testing ,
MP3 USB Flash Drive Micro SD TF Card Player Decoding Amplifier Board Module | eBay
U disk support (tested 32GB), TF card (tested 16GB) Play mode. TF card is the power-on default mode, if TF card is not inserted will play the USB drive. “Repeat” button: “Short Press “, ONCE to repeat the song that is playing.