Remote Controlled MP3 Player With FM Radio

By Sani Theo

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Have you ever considered making an audio system at home? Building your own audio system can not only be fun and exciting, it can give you the same performance, if not better, at a much lesser cost. This inexpensive do-it-yourself (DIY) remote controlled MP3 player with FM Radio and Bluetooth can be made, including its cardboard box, with easily available components and tools.

The author’s prototype for the compact audio system is shown in Fig. 1. It has USB, AUX, and MicroSD/TF (TransFlash) card ports, making it very convenient to interface with external audio systems and storage devices.

Author’s prototype
Fig. 1: Author’s prototype

Collect all the parts and tools required for the project before starting its assembly. These are listed in the two boxes for your convenience and ready reference. The significance of the parts is explained below.

 

Bluetooth MP3 player with FM receiver module

This is the main part of the project. The compact MP3 player module with FM receiver, shown in Fig. 2, is readily available in the market and through many e-commerce portals. It can be installed in your vehicle, desktop PC audio system, home theatre system, or any other audio amplifier.

Bluetooth MP3 player with FM Radio Receiver module
Fig. 2: Bluetooth MP3 player with FM Radio Receiver module

IR remote control

The IR remote control normally comes along with the Bluetooth MP3 player module. But you can also use some other IR remote to control this MP3 audio player. The author successfully tried three different IR remote models, which are shown in Fig. 3.

Common IR remote controls
Fig. 3: Common IR remote controls

Audio amplifier

You can use any audio (power) amplifier having a 3.5mm audio input port.

5V DC power supply (USB)

You can use a 5V, 1A or 2A mobile charger.

FM antenna

It is not very critical. As the MP3 player module does not come with an antenna, you can use a whip antenna or a single-strand hook-up wire as an antenna.

Wires and cables

The project requires a 3-wire cable for audio connection, a 2-wire cable for power supply, and a type-A USB cable. You also need a 3.5mm stereo audio jack with cable for audio output connection to the audio amplifier.

Cardboard

You can use any thick/strong cardboard having a smooth surface for making the cabinet. For a sturdy cabinet, its size should be small. Cardboard DIY cabinets in various sizes are also available on the internet.

To make your own cardboard cabinet, draw the required size for each side of the cabinet on the cardboard using a scale and pencil/pen. After cutting according to the dimensions shown in Fig. 4, place the front, rear, and sides on a cardboard of 8.5cm×14cm size. Fix each side on the base using glue gun.

Author’s cabinet blueprint
Fig. 4: Author’s cabinet blueprint

As can be seen from the top view in Fig. 4, the cabinet has four sections or parts. On the left side, there are two 4.25cm×2cm sections, which are to be used for holding the USBs. These two sections help in keeping the USBs in vertical position, so that they can be picked up easily when needed. The middle section is for holding MP3 player and the right one is for holding the IR remote. All these can be seen in the author’s prototype (Fig. 1). Next, make two holes on the rear side for connecting the audio and power cables.

Fixing MP3 player module in the cabinet

Before fixing the MP3 player module into the cabinet, look out for the antenna point and solder it to the PCB. The internal part of MP3 player module is shown in Fig. 5.

Internal part of MP3 player module
Fig. 5: Internal part of MP3 player module

Fixing the antenna

Use a suitable length (say, 10cm) of single-strand hook-up wire as an antenna. The connecting point for the antenna in the MP3 module is not clearly visible. A hole for soldering the antenna is also not provided in the PCB. However, if you look carefully at the MP3 board on the other side, you can locate the antenna point for soldering, as shown in Fig. 6. You can solder the antenna wire here using a 25W soldering iron. All soldering work should be done before fixing the MP3 module in the cabinet.

Antenna fixing
Fig. 6: Antenna fixing

Soldering the cables

Before connecting the audio and power cables in the MP3 player module, you need to connect the audio cable to an audio jack and the power cable to a USB type-A cable for external connections. Therefore, solder all the cables to respective connectors, as shown in Fig. 7 and wrap them with cello tape, as shown in Fig. 8.

Soldering the power cable to a type-A USB connector
Fig. 7: Soldering the power cable to a type-A USB connector

Connecting the cables to the MP3 player

The 3-wire cable is used for stereo audio connections, the 2-wire cable is for power supply connection, and the single-strand cable is for the antenna. The inside view of the author’s prototype with various cables is shown in Fig. 9.

Cables wrapped with cello tape
Fig. 8: Cables wrapped with cello tape

Note that there is a 4-pin top entry header on the PCB of the MP3 module. But the module comes with a 3-pin wire for stereo audio connection. You should connect it to first three pins of the 4-pin header from right towards the 2-pin red header connector for power supply. The last pin is left unused, as shown in Fig. 9.

Cable connections to MP3 player module
Fig. 9: Cable connections to MP3 player module

Before fixing the module to the cabinet, ensure everything is working properly. When you change the mode in IR remote, it should change to five modes one by one: bt (Bluetooth), USB, FM, SD, and AUX. Testing Bluetooth function in the MP3 player module is shown in Fig. 10.

Testing Bluetooth function
Fig. 10: Testing Bluetooth function

Fixing MP3 player in the cabinet

Fixing the MP3 player module in the cabinet is a no-brainer. From the front side, insert the module into the 8cm×1.7cm slot cut out in the cabinet. Fix it using nuts and bolts. Connect the cables inside the cardboard cabinet, as shown in Fig. 11.

Cables connected inside the cabinet
Fig. 11: Cables connected inside the cabinet

All the cables can be extended to different points from the holes provided on the rear side of the cabinet, as shown in Fig. 12. You can connect to audio source or amplifier through a 3.5mm multiport audio jack, as shown in Fig. 13.

Rear side of the cabinet
Fig. 12: Rear side of the cabinet

The complete assembly of the Bluetooth MP3 player with FM receiver is shown in Fig. 14. The MP3 player module can be powered by connecting it to a 5V DC USB power supply. Its output can be connected to an audio amplifier or amplispeaker to start listening to music. A small desktop stereo speaker system was used to test the prototype.

 Multiport audio jack
Fig. 13: Multiport audio jack

The MP3 player module has USB and MicroSD ports to play MP3 files. Audio from mobile phone or laptop can be listened to by connecting through Bluetooth. FM radio can also be listened to.

Complete assembly of Remote Controlled MP3 Player With FM Radio and Bluetooth
Fig. 14: Complete assembly of Remote Controlled MP3 Player With FM Radio and Bluetooth

The MP3 player can be controlled using IR remote or control buttons provided on the front panel. It also has an AUX (auxiliary) socket, which can be plugged to a 3.5mm standard jack headphone connection.


Sani Theo, technical editor at EFY, is an electronics enthusiast and circuit designer

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