How to Make Your Own Car Stereo-UPDATED WITH a VIDEO

I own a "commuter special" car as I call it. It's a 1989 Toyota Corolla, and I paid next to nothing for it. I had a car stereo in it that I received for free from a dealership that I worked at. It was an awesome flip out touch screen DVD player type. The navigation function was broken which is why it was given to me. Unfortunately, someone else thought it was awesome too; and stole it from my car. Rather than purchase a fancy new stereo for my piece 'o' crap car, I decided to make my own. 

This is my first iteration of this, as with anything that I do I will make improvements. I will be sure to upload any new things I come up with. I also hope to make it a little easier on the eyes. 

UPDATE:

I ran into a few problems with the actual install that were not present when I tested it out the first time.

1. Since I wired the USB port to the same power and ground as the stereo, there was a really loud obnoxious high pitched noise from the speakers. When I took it out of the circuit, the problem went away. So I would recommend putting the USB port onto a separate circuit to eliminate this problem. If you have a newer car with better grounds, this problem might not exist for you.

2. Speaking of grounds, I had to ground the stereo with an extra cable straight to the chassis. This eliminated more noise.

3. I originally wired this to go from both outputs on the speaker board to the speakers. One of these outputs was to a high range speaker, and the other was to a mid range speaker. One of them was causing a super loud really really really obnoxious whine. I'm assuming that this is from car stereo speakers being in different ranges. So if this happens to you, take out that circuit.

4. The volume has to be almost all the way up or there is feedback. Don't know why but just use your device as a volume control.

5. There is buzzing and popping pretty much all the time. It's not really noticeable while the music is playing, but if the music isn't playing, it's noticeable. I would recommend installing a power switch on the front for this reason. 

These are the problems I ran into, I don't know if you will have them because it can vary widely depending on the setup you choose. Overall I am ok with the way it turned out. After all, I only spent $5. If you are looking for a super hi-fi cheap stereo this isn't for you. This is just something cool you can do for cheap that works. 

Good luck! 

- 12 Volt Computer Speaker System or Comparable Speaker Setup
- DC Adapter for Speaker System (the power cord)
-Piece of Thin Particle Board (I used the kind that is rough on one side and smooth on the other it is a 1/4" thick)
-Cheap USB Car Charger with output of 5 Volts (optional)
-Standard 3.5 MM Stereo/Aux Cable
-A Car Without a Stereo
-Assorted Screwdrivers
-Wire Cutters 
-Wire Crimping Tool
-Butt Crimps (Assorted Sizes)
-Razor Knife
-Tape Measure
-Multimeter (not necessary but advised)
-Assorted Screws 
-Superglue
-Wood Glue
-Electrical Tape
-Soldering Iron (not necessary but on some connections I prefer to use this)
-Solder (see above)

Car stereos consist of a few different components. The basic pieces are: 

 - A tuner/signal decoder. This takes the FM/AM waves, or other source information and turns it into audio information. 
-An amplifier. This 'amplifies' the source signal to match the speakers output so that you can actually hear it. 
-Volume/potentiometer control. Turns the volume up or down. 
-Equalizer. Equalizes the source signal, either by manual input or automatic (or both)
-Case/Form Factor. This holds everything together. 

That's what a car stereo consists of. I don't need or want radio, so the way I chose to do this is to take audio signal from phone via the headphone jack and play it through my car stereo speakers. There are a couple of things we need to understand before we do this: 

 The headphone output from your phone/tablet/mp3 player is very low power. If you were to plug it directly into the speakers it would be at a very low volume and you would never hear it. So we have to find a way to amplify it. 

Automotive electrical systems run on 12 Volts. This is important to note. 

The first problem we have is finding something to amplify our sound, finding something to decode our source signal, and it has to run on 12 volts. I found something to do all 3 of these things for me. I used an older computer speaker system, with a 12 volt DC input. This system also has a standard headphone jack as an input, plus a subwoofer out port. I purchased an older Altec Lansing Dolby Surround System for $5 at a local thrift shop. The one pictured is the exact model (but is a photo I found online I forgot to take photos before disassembly). We only need the main speaker. 

TEST YOUR SPEAKER SYSTEM FIRST, to make sure it works otherwise all of this will be for nothing.Take apart the speaker. Remove the amplifier board, and the control board. On the speakers that I purchased, they were two separate boards yours may differ.  Make sure to disconnect the speakers, but leave the wires attached to the board. Take a good look at these boards because you want to be familiar with them, and where the components are located on the boards. 

Measure the dash opening in your car. Mine was 7" Wide, and 2.25" Tall. You will need to make sure that your board(s) fit in here in some sort of configuration. 

Cut your mounting board a little bit less than the width of your opening. The length of it should be a little bit more than the length of your board(s). You can screw it to the board, glue it, or any sort of means of attachment. If you use a glue, make sure it's a neutral non-conductive cure. You don't want your adhesive shorting out your circuit board! The board I used has control knobs that I made sure were hanging off the edge of my mounting board. 

I made a face plate from the same material I used for the base plate. I measured the opening and added a little bit on each side to make it overlap. I measured where the volume controls are, and drilled holes in my face plate to match. Also add a hole for your cable to go through. I then painted the face plate with acrylic paint, and it turned out pretty good looking. I also cut a hole for my USB port. Paint is still wet in the photo. 

Use glue, screws, whatever to attach your faceplate to the mounting board. I used wood glue. Make sure you account for the extra space you added (if any) so that it will sit properly in your dash. 

This is where it can get somewhat intimidating. So pay attention. 

 Cut your power cord about 6-7" from the end. Split it into 2 wires. Plug it into the DC IN port on your board. 

Locate the wires coming from the board and going to the speakers. There will more than likely be 2 sets. 

Locate the input port on your board. Mine is on the back. Plug in your 3.5" MM cable into this. 

If your car has had an aftermarket stereo installed before, it will have the aftermarket wiring harness installed.

The red wire (switched power) from your car will go to the white striped wire from your DC connector. This will make it so your new stereo will only have power when you turn your key on. IF you want it to have power all the time, connect the yellow (constant power) with the red wire. 

The black wire from your stereo harness will go to the plain black wire on your DC connector. 

Group all of your negative speaker wires from the car into 2 groups. Front and back, left and right, whatever you please. 

Group all of your positive speaker wires from the car into 2 groups. 

Connect one of your negative groups, to one of your negative speaker wires on your board. 

Connect one of your positive groups, to one of your positive speaker wires on your board. 

Connect the other sets. 

After you have connected all of your wires, you are ready to finish your installation. Slide it in, and screw it in, tape it in, glue it in, however you decide to fasten it to your car. Turn your key on, and plug in your phone/tablet/mp3 player. Test it out and enjoy. I will upload pics of my finished installation in a couple of days. I plan to add a mount for my tablet so that I can have a cool "In-Dash" display. 

If you want to be able to charge your device, you can add a USB port. I did this by removing the circuit board from a cheap USB car charger. You will just connect the positive wire from the board to the same wire as your other power. The same goes for the negative. 

It's a good to use the pre-made car chargers because they already have resistors/regulators to drop the voltage down to 5 Volts. 

Just glue it or screw it to your faceplate in the hole you created earlier. 

I don't know why some of these pictures are upside down.