UMLIFE 3PCS Mini MP3 Player Audio Module MP3 Voice Decode Board TF Card U Disk IO/Serial Port/AD Board DFPlayer Audio Voice Music Module for Arduino

I had an existing project that uses this chip but from a different project, and it always ran fine. When I put these chips into that project, none of them worked at all. Poor quality. Save you money.

The most BASIC function: grounding pin IO_1 or IO_2 for play next or previous. Longer ground adjusts volume fine. Haven't tried using a library to program my Arduino and ATtiny85 for specific file play yet, but need to soon. The amp function works great with speaker positive to SPK_1, and negative on SPK_2 pins for mono audio on my 4 ohm 3 amp speaker in project box. MicroSD cards hold snug in slot and haven't popped out. NO discernable/significant heat from amp chip, which was a HUGE problem with the BY8301-16P MP3 Module that these replaced. Only issue is on 1 of the modules the header pins are soldered on somewhat slanted and take some fussing to insert in breadboard, but I'm not penalizing a star for that. Will update if I have problems with the Arduino library when programming for this, but until then, I'm very pleased with this purchase

As others have recently noted this unit works fine as a standalone but nothing but issues with serial communication. Tried multiple libraries on Arduino, different arduinos and versions to no avail. Even reached out to a friend who has used hundreds of these (working ones). I ordered a second batch with the same result. Ordered from another seller and those worked with no issues using the latest library from dfrobot. Product images shown on listing do not match what you get. You can see in the attached pictures what to look for. 2 stars because it works fine in stand-alone but hours of frustration trying to get these to work.

I used this device for a music player project. It worked fine for my purposes. Credit to "Richard Makes Escape Rooms" for his tips on using the serial command API. Project source, pictures and video link on my rshorton github music_box project.

First off, these work. And they work quite well at playing MP3 files. However, they deviate from the standard DFPlayerMini spec which might give you some grief. If you're using the ADKEY matrix/button control on this I suspect it should work just fine. I was able to trigger mine just fine via a button connected on ADKEY_1; however I wanted to control it from an Arduino Nano and that was a problem. There were two issues I encountered: the first is that the DFPlayer library (DFRobotDFPlayerMini) simply doesn't work with this device (and I wasted MANY hours trying). Another reviewer (Richard Makes Escape Rooms - https://www.amazon.com/review/R38HBSUUX2VI3Z/ref=cm_cr_srp_d_rdp_perm?ie=UTF8&ASIN=B07Y2YKYRS) posted some EXTREMELY helpful code that manages to communicate with this MP3 player over the UART serial connection. The trick, apparently, is to not send the checksum code; his reviews' code saved my project and enabled me to talk to the device (at least send commands - I never tried receiving a response) from my Arduino successfully. The second challenge I've had is that the BUSY pin seems to get stuck "on". When playing a file, the BUSY pin properly switches to LOW, but then when the file ends, the pin stays stuck at LOW (and the LED light on the player stays on as well). Once in this state, the "Stop" command doesn't seem to reset it -- only playing another track. Ironically, when paused/stopped while playing a track properly switches this pin to HIGH -- so it does work, but not when the track is over. I managed to work around THIS limitation in my Arduino code (by forcing it to play a blank track and stopping it mid-play to fully "stop" the device) but it took a bit of time to figure out this failure mode and code around it. So - depending on your use case this may be an easy fit. Even if you have a complex use case, you CAN make it work (I suspect all of the "knock off" DFPlayer variants here use similar chipsets and have similar limitations).