Posts: 6
Joined: Mon Mar 17, 2014 10:40 am
Location: Hamilton Victoria Australia

Digital Jukebox

Sat Jul 20, 2019 5:20 pm

Last year I bought a Raspberry Pi 3B+, which has become the basis of a digital jukebox with 10,000 music tracks.

The portable jukebox, has the following components:

• Dell Laptop 19.5V 4.62A battery charger (indoors)
• 2 x ALDI 2Ah Xfinity Plus 20V rechargeable battery packs plus ALDI battery recharger
• Australian Telecom 605 Telephone plug (this slides directly into the ALDI battery packs (with the central lug removed)

• TPA3116 D2 Dual Channel Class D Digital Amplifier Board (for the audio side), this will accept any voltage from 15 to 24V.
• Buck converter: This draws some of the power from the Dell Laptop charger (or batteries), reducing it to 5.2V for the Raspberry Pi (comfortably above the 5 volts required but not high enough to fry the Pi.

• Raspberry Pi Model 3B+ with added heat sink on the CPU
• 5 inch 800 x 480 HDMI touch screen monitor

• 2 x 3 inch LG 8ohm speaker drivers rescued from a couple of LG home theatre towers.
• On/Off switch for power
• Volume control knob for the digital amplifier

• 2 x asymmetrical hand-made speaker cases, painted in hammer finish paint with solid brass carry handles, and speaker mesh guards.

• Cordless Bluetooth micro keyboard and mouse (plus stylus for the touch screen.
• 32GB SD Card containing Raspbian Stretch O.S.
• 128GB USB 3.1 Stick with 10,000 music tracks (70GB) mainly MP3, some other formats.

Software: Chromium Web browser
Clementine Music Management suite to play music from the library and access several thousand streaming radio stations
Videolan VLC for watching YouTube clips

I stress tested the device, playing internet radio for 48 hours non-stop, whilst running a number of Linux-based CPU stress tests.
The second speaker is attached via a long lead to enable stereo sound separation.

It boots in 23.8 seconds and the amp has plenty of oomph, my crockery rattles when I crank up the volume.

Some photos:
Clip3b.jpg (38.89 KiB) Viewed 693 times
Components assembled from top right (clockwise): Class D Digital amplifier; switches and external plugs; Buck converter, RPi piggybacked on 5inch screen.
Clip4.jpg (54.21 KiB) Viewed 693 times
Completed unit with Dell power supply, Bluetooth mouse and keyboard.
Clip6.jpg (19.5 KiB) Viewed 693 times
External power supply (4-5 hours per battery): ALDI Xfinity 20V Li-Ion battery pack with modified Australian Telelecom 605 Phone plug.

NB: Once the middle lug is snipped off, the telephone plug slides perfectly In the battery pack.

Posts: 6
Joined: Mon Mar 17, 2014 10:40 am
Location: Hamilton Victoria Australia

Re: Digital Jukebox

Sun Jul 21, 2019 12:47 am

For UK hackers......

ALDI UK sell an 18V battery pack under the brand Ferrex, which looks very similar to the XFinity units sold in Australia.

The TPA3116 D2 Dual Channel Class D Digital Amplifier Board is available from Amazon UK for £5.99 and at for £8.99.

Australian Telecom 605/610 telephone plugs are available via eBay Australia, with at least 2 vendors shipping to the UK.

Posts: 6
Joined: Mon Mar 17, 2014 10:40 am
Location: Hamilton Victoria Australia

Re: Digital Jukebox

Sat Nov 09, 2019 12:41 am

An update:

I was getting a lot of interference generated by the RPi's phono socket. This was a lot of squelching sounds at low volume and a background hum at higher volume. I read that there were issues with the Pi's jack output, so I tried some alternative methods.

First attempt was using a USB sound card. This worked very well, there was no background hum whatsoever and no squelching sounds. I also removed the phono connection altogether (pulled out the jack and unscrewed the wires from the digital amp. The problem then was that my jukebox required two separate power inputs, one for the amplifier (19.5v) and one for the Pi (5v USB 2.0). The dreaded yellow lightning flash re-appeared (under-voltage).

Second attempt was using a Bluetooth receiver with cable connected to the amplifier's 3.5 inch audio socket. This actually has worked out well. No interference, nice clean sound. I was able to retain the single power source (Dell Laptop Charger), with the buck step down converter set to 5.1v (no under-current). I also bought a pair of decent 3 inch speaker drivers (8 ohm) that have vastly improved the sound. It is not quite audiophile grade, but good enough (CD quality).

I'm currently using three applications: Clementine (it provides streaming radio and can manage my library of 10,000 tracks stored on a 32Gb USB drive); VLC, audio only or audio component of video clips; Chromium browser (YouTube clips).

Setting up Bluetooth was very easy,switch on the device so it becomes discoverable, once discovered pairing is easy once.
You also need to select the audio source (right-click the volume icon, select BT receiver.
Update Sept 2019.jpg
Update Sept 2019.jpg (153.22 KiB) Viewed 487 times

Last bumped by bendfeldt on Sat Nov 09, 2019 12:41 am.

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