Introduction: Adding Radio Receiver to Home Audio System
Nowadays with internet radio we are barely using normal (antenna?) radio. I would say it is the best time to have good old reliable Radio available at home and to listen to nice music and Corona-news :)
I am using PC speakers as my main home audio system-enough volume to enjoy it, but not enough (as high end HIFI) to annoy neighbors. It's a system with Bluetooth capability. But it's problematic to stream radio over Bluetooth: iPhone lacks radio receipt as a whole and Android devices(at least my Sony Xperia) require earphones to be plugged to use as antenna (British English: aerial). This routes audio through earphones even though Bluetooth is paired with speaker system. I couldn't get around it and decided to use do this small project- which is my first Instructable.
As Radio receiver I used my 14 years old MP3 player: Creative Muvo Slim 128MB. 128 MB can you believe it? Even though the device works perfect, except it's li-ion battery died years before (the thing is 14 year old, after all!). It has a nice sound quality and packed with functions (for it's time and unfortunately, not useful in this project)such as: MP3 Player(again 128 MB though- 20 songs?) Radio recording, equalizer and so on. Most importantly I appreciate the build quality of the device (which is unfortunately rarity nowadays) and finally it looks fancy, an suits my humble audio setup. I like giving second life to a such piece of history - as my friend mentioned (who owned similar one back in the time), this thing looks nice and bring memories....128mb haha
Existing audio system: can be PC speakers such as mine; HiFi home stereo or even Audio input of your TV(most will be surprised but your TV probably has "audio in" on the back and can act as audio amplifier(this is not the most elegant solution, though)
Radio receiver: In my case MP3 player with built- radio receiver
3.5mm audio jack(both ends)- a.k.a Aux cable.
Power supply: I used 18650 standard Li-ion battery
Some cables and springs to get connected to battery terminals
Step 1: Casing
The casing had to be nice and has final product finish... I used all my skills to achieve it :)
I decided to put in use my new 3d printer, but you can create your case out of sheet(plastic, metal) or wood.
Print time was slightly more than 2 hours.
On the top side I created a tilted housing for the MP3 player.
On the bottom I created a compartment for the li-ion battery 18650 actually stands for the size of such standard(18mm circumference X 650mm length).Of course the compartment was slightly wider(1mm) and longer(2cm) to house the connection terminals. I am using Google Sketchup as CAD software- the source file is attached.
Step 2: Priming and Painting the Case
I used body filler a.k.a Bondo on the casing and sanded it down after 30 minutes to get smoother finish. This is pure aesthetic step and feel free to skip this messy and stinky(do it in well ventilated place) step. Or on the other hand feel free to apply more filler and sand extra time(s) to get perfect finish. I stick to one time since I was so much in a rush to get it finished and publish the photos I took along the process. Finally applied the black paint (can glossy paint). It turned out really nice(better than in photo where because of direct light you see all imperfections). It looks like it's made of MDF and is part of furniture. For super smooth finish few layers of spray primer/filler slash sanding will be required.
Step 3: Connecting Power Cable
For power connection I used scrap car audio cabel and soldered small springs(approx 1cm) thorough small copper plates. This is how I did you feel free to improvise. At the end of the day the idea is that two conductors have to have contact... not very complicated.
I drilled a hole in casing and routed cables from battery compartment into the player and soldered to OEM battery terminals.
The beauty of this project is that MP3 player has battery charge and over discharge-protections circuit built in hence no need in external components. Just plug and play.