DIY 10W Bluetooth Speaker - No Code Needed – How to use a Bluetooth 4.2 Audio Receiver Board with Inbuilt Amplifier (MH-M38)

I’ve just finished up a new tutorial " DIY 10W Bluetooth Speaker - No Code Needed – How to use a Bluetooth 4.2 Audio Receiver Board with Inbuilt Amplifier (MH-M38). Come hit it up!

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For anyone wanting to complete the extension Tim mentioned in this guide and add the built-in rechargeable battery and battery management module, rather than the easier route of using a USB battery bank I’ve got some tips below.

I’ve tested a battery management module (DFR1026) from stock and the default behaviour is that the unit doesn’t supply power to the output unless there is a short-press on the built-in switch to turn power on. A long-press of 10 seconds disables power to the output.

This means the simplest project build can just use the built-in switch on the power management module and no external switch is required.

If you wanted a button that you can use to turn the device on or off from outside the case you could use a button riser to extend that button to outside the case (This is how buttons work a lot of consumer devices ).
Another option would be to connect a power switch between the battery management module and the Bluetooth receiver, this will allow you to power the device with a simple switch you add yourself but this does mean the battery management module is always operating, so your battery life will drain a lot quicker than using the button on the module to disable power output.

Below is a quick sketch outlining the simplest way to wire the speaker project and add the rechargeable battery.

Awesome solution @Trent5487676 :smiley: I wasn’t aware of this product but it’s really a game changer for battery powered maker projects which are usually really tricky. Its easy to charge a battery, and use it to power a project, but this handles charging and boosting in a really well-integrated and affordable package!

I suppose you could even glue a little ‘push rod’ onto the button that pokes out of the enclosure - so you can easily access it from the outside. I’m imagining using a little 3D printed stem, or the tube from a pen ink, or even a matchstick

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Just a follow up with another configuration option. If you wanted to have the Bluetooth receiver module operate with just a simple toggle switch you can use the amended configuration below. As always in integration there are no perfect solutions only trade-offs. The advantages of this system is a simple intuitive toggle control, the downside is the battery management module is always on and ready to deliver power, so the battery life of the system overall will be lower if the device is left unplugged from a charger.
In the event the battery goes completely flat, you would need to plug it back in via USB to start the charging process, then a short-press on the battery management module to re-enable the output power to the Bluetooth receiver.

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I’ve got another wiring diagram for yet another spin on this project. This version uses a different Bluetooth received with a volume control switch so you don’t have to rely on your Bluetooth device to set your volume. Since that Bluetooth receiver doesn’t have a built in amplifier you can then add one like this after the receiver to get the nicer controls with amplification needed to drive the speakers.

This version looks more interesting. But it will need more work.

Hey @Trent5487676 ! Thank you very much for this solution. I’ve been trying the same as your first drawing but the charge/discharge module switch off after few seconds. Do you have any idea ?
The speakers in my system are 2x 2W.
Thank you very much for you answer. best regards:)

Hi Sebastien,

That charge/discharge module doesn’t include a low current cut-off so it should run until the battery is flat once it’s been turned on.
Can you check the voltage on battery you’ve got connected with a multimeter and see if it’s somewhere around 3.7 Volts?
What is the capacity in milliamp-hours of your battery? If you are using a particularly small battery there may be issues with the instantaneous current draw getting maxed out.