DIY Car Stereo System

Almost every car has an FM radio. We can create an easy Bluetooth enabled audio system using a local FM transmitter. Cheap solutions are available online, but this project is a fun, hands-on method that allows you to recycle stuff they already have.

Prior electronics experience and an engineering-related education helps to complete the project successfully. However, there are a lot of resources online so this project might just be the perfect starting point. Electronics for Dummies is a helpful resource available for free online.

Materials Required

· A car with a working FM radio

· An FM audio transmitter board

· A Bluetooth audio receiver board

· A 5V to 3V voltage regulator

· Black, red and yellow electrical wires

· Soldering set

Tools

· 3-D printer

· Glue Gun

· Velcro

· Voltmeter

How To Get Parts

· A Bluetooth receiver can be found in an old Bluetooth headphone

· An FM transmitter is available online at https://www.amazon.com/, https://sparkfun.com/ or https://www.amazon.com/,

· A voltage regulator can also be bought online or be constructed using directions found on this youtube site: https://www.youtube.com/watch?v=zrq4n5tOoTI

Find an FM transmitter (available on ebay, walmart or Digikey.com). Then identify the power specifications and the signal input pin from the data sheet of the specific printed circuit board (PCB) you are using.

In the data sheet for the PCB, you should find the voltage specifications for the board. Most boards have a 5V specification but some have a 3V specification. In case your board has a 3V specification, you might need to use a voltage regulator that you can buy online or build using the directions here.

TIP:The data sheets have a detailed pin map that shows the designation for each pin. A pin is a connection point on a PCB that you can solder electronic connections to. Here you can find good info on how to identify your pins of interest.

Find a cheap but effective Bluetooth receiver board on ebay, digikey.com or salvaged from old Bluetooth devices such as Bluetooth headphones. Once identified, locate the power and signal pins as well.

In the data sheet for the PCB, you should find the voltage specifications for the board. Most boards have a 5V specification but some have a 3V specification. In case your board has a 3V specification, you might need to use a voltage regulator that you can buy online or build using the directions here.

TIP:The data sheets have a detailed pin map that shows the designation for each pin. A pin is a connection point on a PCB that you can solder electronic connections to. Here you can find good info on how to identify your pins of interest.

Use a USB cable as a power connector

Find a micro-USB cable and cut-off the micro-connector to expose the wires. You will find power (red), ground (black) and signal (mostly yellow) wires.

Now that you have all of your pins and wires (power, ground and signal) figured out, solder them all together. If your power needs stepping down or stepped up (voltage needs decreasing or increasing) calculate the appropriate regulator circuit and build it.

TIP: Here you can find a simple guide on how to build circuits.

Check Your Connections and Power (Optional but Recommended)

Make use of your multi-meter to ensure that you are providing your Bluetooth and FM chips the prescribed voltage. Page 235 has a detailed guide on how to use multimeters. Checking your power input will help you avoid potentially damaging your PCB.

Use a hot glue gun to secure all of your solder points. This will help your circuit better withstand the vibrations when you cruise your newly pimped out car.

Design a case for your new stereo system and build it out of any material available to you. 3-D printing a simple box to secure your new stereo system. You can use 3-D software such as inventor, NX or the such to design your case.

Once you have your case, use Velcro to mount the case on your dashboard.

TIP: 3-D printers are more available now than ever. If you have access to a University campus, odds are that they have a printer on site. If not, you can use resources like this to find online vendors for 3-D printed parts.