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Your cart is empty. This product M18/M28/M38 is a low-power Bluetooth design solution, supports the latest Bluetooth 4.2 transmission, 2-channel stereo lossless playback, and the module can be connected to Bluetooth to quickly realize Bluetooth wireless transmission, which is very convenient.
In an open environment, the Bluetooth connection distance can reach 20 meters. Widely used in a variety of Bluetooth audio reception, a variety of audio DIY modification.
Function Description:
Bluetooth V4.2 version, support Bluetooth automatic connection technology, support WAV/WMA/FLAC/APE/MP3 lossless decoding, stereo dual channel output.
After the module is powered on, the mobile phone searches for the Bluetooth name M18/M28/M38, and can play music after connecting Bluetooth.
Module blue indicator light:
When the Bluetooth is not connected, the indicator light flashes quickly;
When the Bluetooth connection is on, the indicator light is always on;
When the Bluetooth is playing, the indicator light flashes slowly.
M18(HW-425):
PIN-------Description
KEY------Button control terminal (4 button functions, additional resistors such as wiring diagram)
MUTE---Mute control terminal (output high level 3.3V when muting, output low level during playback)
VCC-----Positive power supply 5V (lithium battery 3.7V power supply requires short circuit diode)
GND-----GND
L-----------Left channel
R----------Right channel
--------------------------------------------------------------------------------------------------------------------------
Package Includes:
3 * M18(HW-425) Wireless Bluetooth MP3 Audio Receiver Board
GhostToast
2025-09-04 20:21:55
First, I want to point out that I've tried many bluetooth modules lately in a quest to add unobtrusive bluetooth audio pairing to some vintage (1980s) radios. But most importantly - these boards have the most pleasant chime when ready to pair, and upon successfully pairing. It's not a human voice. It's not an incredibly loud sound. It's pleasant and subtle.One of the big reasons I wanted this board was to be able to map media buttons. This has a really fascinating approach (in my opinion) by having one single "KEY" pin which, when grounded with varying levels of resistance, produces different results. This works very well, though you may have to dig deep to find some of the resistors mentioned (although you can also put resistors in series to achieve the same result; i.e. 30k + 3k = 33k). But don't forget to order resistors if you're ordering these, should you not have ones you need and want to use the button function!At first I tried using female header pins and pluggable cables with this board. Instructions elsewhere on the internet state very clearly that the wire's shouldn't be plugged, and should be welded (soldered) - in particular the Ground cable should be sturdy and short. This is to reduce ground isolation noise, which i definitely experienced. It can be alleviated by soldering everything, or putting a B0505S-1W between the power supply and this unit to help isolate the noise.You'll also want to make sure the 5v fed to this module is on it's own power rail as much as possible, and not shared off of some borrowed component of another device. In my case, I spliced the 120v AC just inside the radio and tapped it into cheap AC-DC converters (like a USB phone charger wall wart) to provide a stable 5v without signal interference.And having the buttons is great. There's even an indicator when you've hit max volume (for what it's worth, it starts at max volume, and since it's not amped, this is ideal). The volume that can be changed on here is independent of your Bluetooth device (phone) volume level.Anyway, like the title says, if you know what you're doing or willing to learn a little, these are great boards for the money. And they're the size of a postage stamp so you can add them to practically any project or existing stereo/radio.
Daniel Bjorke
2025-08-10 13:11:34
Okay, the good first, obviously.The pairing and power-on sounds are simply the best I've come across so far on my years long Bluetooth module experiments and sampling. The ON-sound is a low volume four note ascent with swell; I find it to be very pleasant overall. The pairing/paired sound is like a digital star twinkle sound, also very quiet in volume.This low volume, unobtrusive sound set this unit has is THE BEST. In my search for the best Bluetooth module, I've found most sounds they make to be obnoxious and sobering. There should be a pad set on all Bluetooth modules that one can short out to cancel all power-up / pair sounds; isn't the LED enough??The Key functions are pretty cool. Try not to overlook the V+ / V- piggy backed on the track advance and back features. They are not kidding about the resistor values. I really like this unit a lot.Now for the bad elements, and there is only one I have found...-The overall output volume is weak. Like, very weak. As an example - if you plug a 1/8" to 1/8" male-male cable into your lap-top and play a 100hz test tone on Spotify and measure the AC voltage at the other end of the cable (level produced by comp) you're likely going to see something near 1VAC. The majority of "good sounding" Bluetooth modules will produce something around ~0.200mv AC when playing the 100hz Spotify test tone. ~0.200mv is a usable and strong signal strength; I would submit even ideal. The MH-M18 outputs ~0.068mv AC. This is mighty low and will require some means of amplification. The MH-M28 seems to be outfitted with a jack and I would assume it has a more robust output, but it is also outfitted with the USB hardware, a pity.If the volume were 3/4 stronger the unit would be an absolute knockout - 10 out 0f 10. I would say it's a strong buy though, even with its low output level.
Tony
2025-08-08 09:49:45
I used them for two different projects so far, and they sound really good once they are going. They can be a bit static-y at times, but that may have been the way they were wired (when testing with another chip a different way I had no issue whatsoever).
noodle
2025-07-14 17:46:16
bought this because there was supposed to just be a beep sound effect that plays when you connect, disconnect, etc. Here to tell everyone, maybe they changed the manufacturer or programming - there is no beep sound effect, it is indeed a Chinese lady saying, "the bluetooth device is connected", etc, like every other bluetooth module. Other than that it works well.
Omerta
2025-07-05 10:59:25
It's ruff looking but it works and it was fun to put together, if you are using a 3.7v battery you will need to take out the resistor right in line with the "key functions" solder point on the other side, just breaking it off and create a bridge with your solder to replace the resistor.
Chuck
2025-05-22 13:44:37
Had no problem wiring them up, getting them to connect to a phone, and play but don't expect noise free music. They create quite a bit of low level noise from what I assume to be digital hash made worse by insufficient decoupling on the board itself. Also the trace layout and grounding path on the circuit board itself is far less than ideal. There is no separate audio ground from the power supply ground. I tried adding extra capacitors to the board but could only do so much. If you are using this simply to make something have a Bluetooth connection like for phone calls or some other non musical application it should work fine but if you are trying to connect your phone to your stereo for music and podcasts and such I recommend something else as the noise is noticeable. FYI I used a 7805 linear regulator and the standard filtering and it seemed to be happy, apart from the noise.
Seb
2025-05-04 15:58:40
J'ai pris ces modules pour equiper enceintes de Monitoring Prodipe POD 3 pramplifiées.J'ai reconverti l'entree réservée aux Iphones.(Station d'acceuil obsolète).Cela fonctionne à merveille.Livraison rapide.
Mohsin Raza
2025-05-01 12:56:46
Good work Bluetooth receiver
Luigi T.
2025-04-22 14:55:25
I moduli funzionano bene, consiglio il montaggio del condensatore e dell'impedenza sull'alimentazione per evitare disturbi, come riportato sulle specifiche di questa famiglia di dispositivi facilmente reperibili in rete. Ne ho utilizzati due senza problemi, viste anche le dimensioni ridotte. Ottimo rapporto qualità prezzo, arrivati imbustati singolarmente.
Marco
2025-02-11 20:44:01
Scheda alimentata a 5v collegata a 2 casse da 3 w , 8 ohm, per semplicità collegata ad un amplificatore PAM8403.Testato l'ingresso KEY, per simulare i vari tasti, funzionante.Inizialmente l'alimentazione era in serie con un motorino ed una striscia led.Ogni volta che cambiavo colore dei led, il calo di corrente influiva sull'audio.Provando il loro filtro LC che riportano sul loro datasheet, non ha risolto.Ho dovuto suddividere le alimentazioni, attraverso uno Step-UP DC-DC.Volendo avrei potuto collegarla a batteria esterna.Scheda che fa il suo lavoro, ma molto sensibile.
Andrea F
2024-12-16 12:38:44
Acquistato per realizzare piccola cassa bluetooth mi ha soddisfatto per la qualità audio e le piccole dimensioni.Si trovano comunque i pad di connessione per uscita, mute ecc. Buon prodotto visto anche il costo contenuto.
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