MP3 Player Module with Bluetooth

This MP3 player module with USB and Bluetooth V3.0+ EDR wireless (also known as, Bluetooth Speakers JQ-D015BT) can decode MP3, and WMA music files stored on USB memory stick or micro SD card. In addition to Bluetooth, it also has an on-board FM receiver. Supplied with remote control and wires, it is ready for installation into homemade speakers, cars or motorcycles that use 12 V or less for their electrical systems. To install this successfully, you will require a DC power supply within the range 5 V to 12 V, and a power amplifier capable of driving a loudspeaker. Bluetooth is a very useful facility to have as it enables a Smartphone to transmit audio to a module such as this, which then feeds an amplifier to drive a larger speaker. There are many homemade style hobby projects where hobbyists make their own Bluetooth speakers out of cardboard boxes by installing this module together with an amplifier and power supply. The plastic panel of this version of the module measures approximately 108 mm × 25 mm and the screw spacing is 93 mm (approx).

Review

With the advent of the Smartphone, the development of System on Chip (SoC) with ARM technology is always progressing, and here we see a very useful piece of electronics in the form of a module that could fit into almost anything to provide added functionality. This JQ-D015BT module has the AC181IDE1234-01 SoC manufactured by JL (logo that looks like a PI symbol). It has built-in music decoders, Bluetooth circuitry, memory card interface, and display drivers. By placing everything on a single chip, there is virtually nothing on the board except some SMD resistors, capacitors, and a clock crystal. However, all of this is good for the consumer because you get something that costs virtually nothing to produce and use. SoC technology is progressing at a fast pace and factories in China are already producing the next generation of modules that can decode audio and video. Consequently, there is a huge selection of modules offering a wide range of functions for all sorts of applications.

I was not able to find any information about the AC181IDE1234-01 SoC, as these technologies are usually kept secret. Manufacturers usually do that when they want to prevent anyone copying their designs. However, if you have a block diagram or datasheet, then feel free to send it.

If you have not bought one of these already, then you will be interested to know that there are three versions of this module varying in length. Type A is 108 mm, type B is 92 mm and type C is 85 mm, therefore if you are planning to install it into something already existing, then you have a choice of getting one that is the correct size.

One down side of this module was that there was anti-aliasing and digital noise in the analogue signal, and although it disappears with increased volume, it cannot be hi-fi quality. The analogue signal through Bluetooth was also noisy with digital noise being prominent. Perhaps it was just my module that may have been faulty, and perhaps the manufacturer may address this issue in future models.

The 9 mm × 36 mm LED display panel consists of four digits of 7-segments each. It has fixed symbols for play, pause, USB, SD, FM, and MP3 functions.

One thing to look out for is the digital noise in the audio during Bluetooth mode. Although one can drown out the noise by increasing the volume, the level of crosstalk is a concern for those seeking hi-fi quality. Perhaps it was just my module or a bad batch, but it is worth checking to make sure. Please bear in mind that this board is just the decoder, and you will need to feed its output to a power amplifier with speakers. A stereo amplifier with its own power supply and speakers are usually required and there is a wide array of options for the constructor depending upon the specification.

Cost/eBay

Bluetooth modules with USB MP3 are usually for sale in a mind-numbingly large array of variations ranging from little circuits the size of stamps, to large modules with switches and buttons. The one shown in this article was the cheapest and best one costing only £2.50 including postage and came all the way from China. It came in a small plastic bag together with the remote control and wires to connect to the sockets. There is no manual as the unit is so simple to use and requires some common sense.

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