Bluetooth 5 Hard Drive Audio Player

I have looked at many Instructables in the last few years and often thought about writing one myself but having the time is always a problem. However, when I spotted the “Trash to Treasure” contest it occurred to me that my recently completed project just may be an appropriate entry, and so prompted me to produce this Instructable.

This is my very first Instructable and is perhaps more of a “what you can build from pre-used and scrap parts” type of Instructable than a fully detailed “how to make it” Instructable, if that makes any sense!

I didn’t have any thoughts on publishing this as an Instructable during the build of this project and so it may be lacking in some areas. However, I hope you will find it interesting and maybe give you some ideas for your own future projects.

I always try to take photo’s of my projects as they progress and store the project details in an App on my computer. This enables me to refer to them later as necessary because my memory is now not so good as it was when I was younger. The App is called “GoodNotes” and I have found this to be really good and worth a look if you are interested.

The Inspiration

I watched a youtube video where the you-tuber had used an old computer hard drive as a simulated mini record player and used a DF Player (SD card) module for the music source. https://www.youtube.com/watch?v=-LPTfaiOgq4

I was quite impressed with this and thought I might make something similar. My thoughts were that I could perhaps make it as a present for my son, as he might find it a novelty, him being in the IT business.

The Initial Idea

My idea was to make an MP3 player using one of my son’s old 3.25 inch hard drives which would actually spin whilst playing and the arm would move across the disc and so look like it was accessing the music from the hard drive itself.

I wanted to utilise as much pre-used and scrap materials from computers as possibly so I searched my loft and workshop for anything that might be usable within the computer orientated theme. Some of the old parts that I used are listed below.

These are some of the parts that I used for this project. You will no doubt find other appropriate bits and pieces if you decide to make something similar.

Seagate 3.5” Hard Drive (pre-used)

5.25” Floppy Disc Caddy (pre-used)

Metal chassis part from old computer tower case (pre-used)

Scrap metal aluminium and plastic pieces (pre-used)

Screws from old Hard Drives and computers (pre-used)

Short lengths of wire (pre-used)

3 x PCB mount mini push button momentary switches (pre-used)

Telescopic aerial from a transistor radio (pre-used)

Bluetooth Module RX-888 (VHM314??): https://www.ebay.co.uk/itm/274430870916?var=574561218859. From Aliexpress: https://www.aliexpress.com/item/32963932555.html?spm=a2g0o.productlist.0.0.4d033a95K7lQV5&algo_pvid=8ee57a3b-abaa-4f22-afce-161f4225517d&algo_exp_id=8ee57a3b-abaa-4f22-afce-161f4225517d-0&pdp_ext_f=%7B%22sku_id%22%3A%2210000015290374245%22%7D&pdp_pi=-1%3B1.71%3B-1%3B-1%40salePrice%3BGBP%3Bsearch-mainSearch

Amplifier PAM8403: https://www.ebay.co.uk/itm/254590266239?var=554324196166

2 x Speakers 8 ohm 3 watt: https://www.ebay.co.uk/itm/303993412455

Motor driver board: https://www.ebay.co.uk/itm/224929641830?_

Voltage Boost module: MT3608 (2-24v 2A)

Voltage Boost module MT3608 (2-24v 2A): https://www.amazon.co.uk/gp/product/B079H3YD8V/ref=ppx_yo_dt_b_asin_title_o00_s00?ie=UTF8&th=1

Li-Polymer battery: https://www.amazon.co.uk/gp/product/B08ZCQXFX4/ref=ppx_yo_dt_b_asin_title_o02_s00?ie=UTF8&th=1

3 x Slide Switches (2p2w on/off)

PCB mount sockets and matching plugs (JST HX 2.54)

The case I wanted to use was an old 5.25 inch floppy disc caddy box which I’d had for over 30 years (it was marked as “made in West Germany”!) which does give it’s age away. It was ideal because the 3.25” hard drive fitted almost perfectly into it and it had a clear cover lid which was great as it would offer protection for the drive and allow for the drive to be seen working. As it turned out the clear case material which I think is styrene was quite fragile and easily cracked when working with it, however, I did manage to make a quite reasonably finished article albeit with a few minor scuffs and scratches, age and use related.

I initially tried using the Hard Drive complete with all its electronics but was unable to get it to run continuously howeverI am sure this is possible if you know how. So for me to enable these functions I bought a motor driver board to spin the discs and used the speaker output from one channel of the amplifier to move the drive arm across the discs according to the actual music being played. I did consider using a transistor amplifier to drive the arm but found that driving directly from the speaker output worked ok, at least I could’t hear any noticeable difference in sound output.

I originally ordered the DF Player used in the youtube project and a small amplifier module, I then discovered the Bluetooth modules which were available and decided this may be an easier option as it would be possible to stream direct from a phone rather than having to load an SD card with music.

Unfortunately the easier option of ready made complete Bluetooth units, which were generally for use in cars and other projects, were all too large for the case I had chosen for my project so I had to settle for a small module and add the controls separately. Because the case was small it also limited the size of the speakers that I could use and potentially the sound quality and output.

I ordered a VHM314-3.0 Bluetooth module which I thought would do the job, however the module I received was somewhat different to that which I had ordered. I spent some time trying to find information on this different module, without much success, but it did seem to be similar, if not visually the same, as the VHM314-3.0 module. I eventually found a supplier on Aliexpress who was selling this module, but unfortunately not much information given on the site.

There was one notable difference with this module in that it had a Micro SD card slot I assumed for MP3 music files, which did turn out to be the case and was a bonus.

Whilst playing with the module I discovered that it also had an FM radio built in so again another bonus but it did mean that an aerial was now required which meant some alteration to the original case design.

The Bluetooth module had built in battery charging provision which I thought would simplify construction, however this turned out not to be the case and it would have been better to have a separate battery charging module. The output from the voltage regulator of the Bluetooth module seems to be barely adequate for the module let alone for anything else. This made it more difficult and led to other annoying minor problems that were not so easy to address.

I used a small through holed PCB board to mount the Bluetooth module, audio amplifier and amplifier power supply.

The Bluetooth module was unable to provide the necessary power to the amplifier and 5v was required for the audio amplifier so a PSU boost module was needed to raise the 3.7v from the Li-polymer battery to the 5v required for the audio amplifier. A 470 micro-farad capacitor was added to the output of the audio amplifier PSU to help with high current peaks that may be required by the audio amplifier. The PCB board also allowed the mounting of the mini PCB push buttons, for direct player operation, and the connector sockets for off-board switches and speakers.

The PCB board was housed in a small metal chassis, which was removed from an old Tower PC case, which fitted absolutely perfectly into the project case, as if it was made for the job. I just needed to cut out holes for the speakers and a few minor alterations to get it to fit and secure it in place.

It was necessary to solder fine wires from the micro push buttons on the Bluetooth module to the mini PCB buttons to enable control of the player functions other than by the remote control or the mobile phone. I left the micro push buttons in place on the Bluetooth module as it would probably have been more difficult to remove them. Soldering wires onto such tiny connections is not for the faint hearted! The PCB mini push buttons were recovered from an old PCB in my electronics scrap bin.

I used JST 2.54mm PCB sockets and plugs to make it easier for assembly and disassembly of the off-board parts from the modules PCB. It did all start to get a bit tight in the case and the final assembly, whilst not difficult, needed care so as not to trap any wires.

Because the top of the case was clear it was necessary to make an insert to cover the internals, this was made from a thin black plastic divider from an old A4 clip folder found in the cupboard. I used white “Letteraset” rub down lettering for the marking of the controls, again this was found in the cupboard and would be over 30 years old, but still worked. It can not be worn off as it is protected by the clear case cover.

I machined the small aluminium push buttons, the speaker bezels and the aerial mounts from some scrap aluminium found in my scrap metal box. I also used some aluminium bar from an old computer which looks good too. The aerial was from an old transistor radio from the 60’s or 70’s.

The back panel for the switches etc was fabricated from an old plastic calculator stand from many years ago.

Two small (23mm) 8 ohm 3 Watt miniature speakers were used for the stereo output. These speakers are enclosed in their own boxes so it makes for an easier installation and possibly better sound quality.

The infra red remote control receiver sensor was unsoldered from the Blootooth module and mounted remotely behind a small transparent acrylic disc on the side of the case. The acrylic disc was machined from a scrap piece of acrylic sheet. The sensor was reconnected to the Bluetooth module using 3 short wires soldered between the PCB and the sensor legs.

The Hard Drive motor driver board was modified to enable it to be fitted under the Hard Drive. The screw connectors were desoldered from the board and removed. The motor speed adjusting potentiometer and the electrolytic capacitor were also desoldered, the potentiometer was replaced with a smaller flatter one and the capacitor was laid flat on the board and re-soldered to reduce height. The HD motor driver board is suitable for 3 or 4 wire HD motors, mine was only 3 wires which I connected by guesswork, the common, for 4 wire motors, was not used. There is a motor direction 3 pin plug on the board that uses a simple 2 pin link plug to choose either clockwise or anticlockwise rotation, I had to bend the pins at 90 degrees to reduce the height.

The Li-polymer battery was chosen for it’s capacity and small dimensions. I had wanted to use a larger capacity battery but could not find one small enough to fit within the case. The battery will drive the Audio Player, without the Hard Drive effect, for 5 to 6 hours depending on volume so not too bad. I haven’t tested it for duration using the Hard Drive effect which will obviously be significantly less. Naturally it can be used with the USB input from a 5v adapter or power bank if the Hard Drive effect is required for any significant time, so not a big problem.

I produced a wiring diagram for the off board components to help with wiring the JST plugs and sockets correctly. The other wiring on the PCB was just worked out as I went along, so no diagram produced.

All the screws used in the construction were removed from old computers and hard drives.

I produced an “Instructions for Use” of the Audio player with a few important user notes:

Bluetooth BT 5.0 Hard Drive Audio Player Instructions.

The BT Audio Player has bluetooth 5.0 functions, FM radio and MP3 SD card function.

To listen to music through headphones: plug in to the 3.5mm headphone jack and slide the “speakers” switch to the “off” position.

To listen to music through the speakers: slide the “speakers” switch to the “on” position.

To enable the Hard drive simulation effect whilst playing: slide the “effects” switch to the “on” position. Note that the “effects” cannot be used when using FM radio function because the HD motor causes severe interference, slide the “effects” switch to the ”off” position. The FM signal needs to be strong for good hiss free reception.

The first time you turn the BT Audio Player on you will need to pair with your mobile phone or other Bluetooth device. On your phone go to the Bluetooth setting and look for RX-888 and pair with this device.

To turn the player on: slide the “power” switch to “on”. The BT Audio Player will announce “the bluetooth device is ready to pair”. Once paired you will hear a “ding-dong”, you can play music from the paired mobile or other paired device.

The BT Audio Player can be powered through the micro-USB port connected via a USB cable into a 5v USB adapter or computer 5v USB port. However, it is VERY IMPORTANT that the “power” switch is in the “on” position before connecting the USB to the 5v supply. This is because the BT Audio Player cannot supply adequate current to the unit if the “power” switch is not in the “on”position so the BT Audio Player will not function correctly.

The BT Audio Player is powered by an internal Li-po re-chargeable battery which is automatically charged whilst the unit is playing and the USB lead and charger are connected and the charger is turned on. It can also be charged via the Micro-USB port whilst not listening to music, however to do this it is necessary to have the “power” switch in the “on” position, “speakers” switch in the “off” position and preferably use the remote control to turn off the music.

IMPORTANT: Remember to slide the “power” switch to the “off” position and disconnect the USB cable when charging is complete, otherwise the unit will discharge itself.

IMPORTANT: Always remember to slide the “power” switch to the “off” position when you have finished listening to your music otherwise the internal battery will discharge.

The volume can be increased or decreased by using the buttons on the BT Audio Player. For volume press and hold. For the next track or previous track short press of the buttons on the BT Audio Player. The “mode”, “Bluetooth, FM, SD card can be changed by a long press of the “mode” button, or the music can be paused by a short press of the button.

The remote control can be used for more functions mostly self explanitary by the symbols on the remote control. The EQ can be cycled through 6 settings by short press of the “EQ” button. The FM radio channels can be searched for by short pressing the green button and short press again to stop search. Channels can be selected by pressing the black buttons “forwards or backwards”.

I have built many electronic and other projects over many years and get great pleasure from recycling old equipment and parts. I just hate throwing things away so my workshop and loft is full of useful stuff.

I am very pleased with the end result of this project and it is possibly one of my favourites. There were a few challenges, not least squeezing it all in to the case, but it has been absolutely worth the effort. The sound quality is far better than I had hoped for and the Hard Drive effect is really good. There are a very few niggles that if I were to build a similar project I would try to correct, but overall I am really pleased with it.

I do hope you will be encouraged by my project to build something similar or that it has given you ideas for your own project. Thank you for looking at my first Instructable, I hope you have found it interesting.