Hello all. I would like to introduce you to a cheap Chinese MP3 player - DFPlayer Mini. The cost of such a player is less than $ 1.5. DFPlayer mini has the ability to play music in MP3 or WAV format from the built-in micro SD card reader, you can also play music by connecting a USB flash drive to the player. The storage medium should not be larger than 32GB and should be FAT16 or FAT32 format. This player has the ability to control both by connecting goldpins and through the UART interface with a speed of 9600 bps. It has dimensions of 20.5 x 20.5 x 13 mm. I became interested in the player after reading the article of one of the forum users, where he described a changer emulator he had created for cars of the VAG group. https://www.elektroda.pl/rtvforum/topic3380561.html The player was ordered directly from China, after 3 weeks it was in my hands. Basic "analog" control is shown in the picture below. This way, you can turn on the next / previous track, turn it down / up. You can connect a small speaker directly to the player - I used 1.5W 8?. Unfortunately, the device has an output only for one loudspeaker, but you can get stereo through the DAC_R, DAC_L outputs where you should connect them through an amplifier or you can connect headphones here. The device can be powered from 5V, power consumption less than 15mA, increases when you connect a USB device. Tracks recorded on a storage medium should be properly named - e.g. 001, 002 etc. Tracks should be grouped in folders that are also numbered - 01, 02, etc. The maximum number of folders is 99 and the maximum number of songs in a folder is 255. If we do not use the control that turns on the appropriate track number, we will only use the previous / next track, then tracks and folders can be named freely. Below is the player pinout As for communication via UART, use the settings as in the picture below. It should be remembered that although the device is powered from 5V, the UART voltage level is 3.3V and for this reason, a 1k? resistor should be added between the Tx of the device sending the commands and the Rx of the player (if we use the 5v standard in the device sending the commands, at 3.3V the resistor is redundant). I used a 10k? resistor because I had one at hand. The video below (sorry for not the best quality) shows sending commands using the COM Port Toolkit program and the USB-UART converter based on the FT232 chip. [movie: 6bf572119f] https://filmy.elektroda.pl/83_1511229427.mp4 [/ movie: 6bf572119f] The basic commands are: - next 0x7E FF 06 01 00 00 00 EF - previous 0x7E FF 06 02 00 00 00 EF - quieter 0x7E FF 06 04 00 00 00 EF - louder 0x7E FF 06 02 00 00 00 EF The above commands do not include checksums, they can be sent without sums or with a checksum. How to calculate the checksum? We count it in hexadecimal. The command with the checksum for switching on the next track is: 7E FF 06 01 00 00 00 FE FA EF where FE FA is the checksum. We need to add FF + 06 + 01 + 00 + 00 + 00 = 106 together 0-106 = FA EF which gives our checksum. When sending a command to the device, you can request a response and it will be clear that the command has been understood. In the video below, a short presentation of the player control through the AVR processor which supports the buttons (NEXT, PREV, VOL +, VOL-) here, then sends the appropriate commands, receives from the device information about the current SD card or connected USB drive and sends the command 0x7E FF 06 01 00 00 00 EF for sequential playback of tracks. There is also a remote control via IR. [movie: 6bf572119f] https://filmy.elektroda.pl/18_1511229716.mp4 [/ movie: 6bf572119f] The disadvantages that I noticed with this player are the inability to connect a second loudspeaker, no possibility of scrolling, no memory of the track being played after turning off the power and the volume set, no possibility to play songs in the order with "analog" control (feeding the mass to the appropriate goldpins) - after the end of playback track, you have to force the next track to play, this problem can be avoided when controlling via UART.
The player can be used to build a watch where you can hire it to play the bugle call at the full hour or as a wake-up call, an MP3 doorbell, etc. Below is the documentation for the DFPlayer mini.
Allow me to attach a handful of comments to expand the description.
1. The module can act as a card reader. After connecting it to the computer, the playback is interrupted and the inserted SD card is visible in the system as a normal USB memory. I recommend connecting the uUSB socket to the module and alternately connecting a standard USB cable or a USB OTG cable to it (a USB memory stick is plugged into the socket). Pay attention to the supply voltage!
2. If we are talking about voltage, the guts of the module are powered by 3v3 voltage which also powers the USB, SD and UART interfaces. The module has a built-in stabilizer and can be powered with voltage from 3v3 to 5v. Therefore, the entire module can be connected to 3v3 and 5v only to the USB socket.
3. According to the documentation, the checksum and response request are recommended when uC is clocked with the built-in RC oscillator or ceramic resonator. When using quartz, the checksum can be omitted, not sending these two bytes. I fired my module using the arduino library that sends the checksum. Unfortunately, I currently have no way to check whether the module will work without checksums. I gave my art in the name of a higher idea, I am waiting for another one.
4. There are also other addressing modes. For example, you can address 3,000 files in a single directory or suspend the current music, play a short message and go back to suspended music. Unfortunately, I will not check that either.
I am not an audiophile but for me the sound is ok in the loudspeaker and headphones, I tested it in the car and it sounds quite good to me. As I wrote earlier, one of the users made a car changer emulator on it, so let me quote his statement:
Just back from assembling in the car. Earlier, I wrote that the audio signal quality is very good. I made that statement by looking at the oscilloscope while playing test signals on my desk. Now I can say that I wouldn't change anything. Everything from the sub-bass to the whistle works. I do not expect a complaint. best regards
I cannot complain about the sound quality. Only interference occurs when uC is sending data to the module. This is how I used uC powered by 5V and gave a 2k resistor on the uC-> module data line.
However, the module lacks: - reading the current playback position, - rewinding or playing from a specific point in time, - access to the file system, e.g. reading the name of files / directories, - the simplest play queue, eg the command "when you finish the current file, open the indicated". I guess I'm asking too much It remains to look for a better alternative at an equally attractive price.
I have 10k and I can't hear any noise. As for reading the current position, you can set a timer that will count from the moment of information from the player that a new track is coming and reset it when the information about playing the next track appears again. Queuing could also be done, you only need to hire a processor. If the songs are to be played one after the other, from what I remember it is command 11. There is no reading of the track names and no scrolling what I wrote about at the beginning.
I have two questions regarding this module: 1) Is there a 10 ohm resistor on the USB D + and D + lines ??? Usually, I have encountered such a solution, is it here on the module? 2) What size capacitors should I give for DAC_L and DAC_R ?? Are these also on the module ??
Hello, encouraged by a simple mp3 player, I bought this module. I connected according to the instructions (from the very beginning of the post). 3.3V battery power, 0.5W 8 ohm speaker, and unfortunately it doesn't work for me. 1 GB micro SD card with FAT32 formatted and uploaded file 001.mp3. after turning on the power, nothing happens, when I press playback, the light on the module lights up, then it goes out and a short humming sound starts from the speaker. After that, everything goes silent. Do you have any ideas on how to start it? I will be grateful for any idea. I only have a meter and a soldering iron
@ wojdyl1 , I bet that the amplifier and speaker overload the 3.3V stabilizer, the voltage drops out and therefore everything turns off. Try to connect speakers with an amplifier to the line output, or as a last resort headphones through a serial capacitor between the stereo output (one channel is enough) and ground.
The second option is as advised @ grala1 , increasing the supply voltage. In my opinion the 3.3V supply voltage is too low for this module. The "guts" of the module and the SD card require a voltage of 3.3V, but the player has a built-in stabilizer. In my opinion, the supply voltage should be at least 3.6V (discharged li-ion battery) and max 5V. The only thing you need to be careful about is the controls. If you connect the player to a 5V microprocessor, you need to add a serial 1k resistor on the uC (TX) -> player (RX) line.
Thank you very much for the hint, I checked and everything is correct, the loudspeaker was too heavy on the module. Now I plugged in the earpiece and everything started to work. Thank you again.
Added after 40 [minutes]:
I have one more question, what external speaker can I use for the module so that it works well reproducing the speech, only 3.3V power supply without amplifier. Headphones are not an option. What were you using?
The player has two audio outputs that work simultaneously. One is a stereo line output (poor performance), the other is a mono output through the built-in amplifier (separate circuit on the PCB).
Your speaker problem may lie in: 1.too weak 3.3V power supply (the voltage drops under load), 2. damaged amplifier or loudspeaker (I doubt it), 3. the amplifier is just so designed that it does not want to work with a low supply voltage. Please write where did you get 3.3V voltage and why can't you use higher voltage? A lithium battery usually has a higher voltage and in most stationary devices you can find a voltage of 5V or higher (a stabilizer is included). If you can't win with the supply voltage, replace the speaker with any other one (maybe the one has a short circuit) and put voltage filtering capacitors near the player. If both of the above methods fail, then playing with a special loudspeaker will not be of much use. The final solution is to add an additional amplifier. For example, PAM8302 available e.g. here: https://www.adafruit.com/product/2130 will work at 3.3V and in combination with a 4? speaker you have a chance to get almost 1W power.
it turned out that the power supply did not give the correct current and therefore the module could not cope, and only with a low load you could listen to something. I installed the batteries on the phone and everything started working. Thank you for your help.
Hi. I wanted to assemble a toy for my little ones on this particular layout, but I have a problem. I wish I could run 36 songs with 36 buttons. I can see that direct control can be done via ADKEY1 and 2 ports but unfortunately selecting tracks with this method ends up at position 14. So the control had to be done through the arduino and the RX and TX ports. I just don't know how to do it. I found the KEYPAD library here: