Assalamulaikum all.
Today, I'll be sharing a DIY I did in my corolla and would also highlight the things needed for the DIY so you can also do it in your cars.
This is the headunit on which the DIY was performed. 10 years of age and still going strong!
The headunit, that used to come originally with corolla back in 2003-2004, does not have an 'auxiliary-in' let alone a usb feature. My mission was to convert the stereo to play a USB and provide a 'line-in' for my cellphone.
This is the usb controller that I'll be using. Ugly? I hear you. That shall be taken care of later down the diy. The controller can read a Usb, sd card and has the options of 'line-in' and a radio. Costs around Rs.300 with the remote and is easily available at electronics shops that sell spares.
Now the things that were required for the Diy,
1. An L7805cv transistor / regulator (since the usb controller runs at 5volts, you'll need this to drop the voltage from 12v to 5v).
- Heatshrinks or Electrical Tape.
- Power / Led connectors from an old pc case (If your stereo does not already have an 'aux-in / line-in' option).
- Some wires.
- Soldering Iron and wire.
- And creativity to find a place to install the controller in the car.
These are the Cables that the USB controller came with. It has 2 seperate grips, one for audio output and the other one for power input.
The USB controller taken apart.
Wires Soldered on to the transistor / regulator.
Input being the 12v from the battery and the output being 5v to the controller. I've connected the 12v input to the remote 12v cable at the back of the headunit so that the usb controller turns on with the headunit (the remote 12v wire is there to send a signal to the amplifier to turn on).
Now the transistor needs to dissipate heat so that it doesnt get burnt out, so you'll need to either attach a heatsink to it or screw it onto an already available heatsink in the vicinity.
The headunit already had a heatsink at the back so I screwed the transistor onto it like so.
This here is the ip-bus port at the back of the head unit to which the cd changer is usually connected.
If your headunit already has an audio-in option, you dont need to use the ip-bus port. Just connect the audio cables coming from the usb controller to the RCA inputs at the back or the 3.5mm port.
This image will help you decipher what pins do what. We'll be needing 'Line-in' for both the left and the right channels.
Once you've identified these pins, you need to insert the power / led connectors onto the pins. It should be a snug fit. Once you have done that, you need to connect the cables to the audio out of the USB controller, locating the connections on the back of the pcb.
Now you need to do the same thing to the power connector on the usb controller. You need to feed the 5v coming from the transistor to the controller.
Voila! Your headunit can now play USBs. All you need to do now is to place the USB controller wherever appropriate.
Once it was all connected, I went ahead and installed it all in a way that it looks oem (well, somewhat ).
I've placed the screen and the controller behind a piece of smoked acrylic cut to the size of the place that used to hold the clock in the center console. Through the acrylic, you can only see the display and use the 3.5mm jack.
Now since the fascia and the buttons on the controller looked ugly, I had to make new buttons and find an appropriate and easily accessible place to mount them. I soldered wires onto the pcb where the stock buttons are soldered and extended the wires. Then I shaped a piece of acrylic and mounted some buttons onto it and installed that piece next to the headunit. Looks neat no?
I also soldered a USB extension cable onto the pcb and extended it into the ashtray and placed the usb there (Sorry for the dusty ashtray ).
Total cost: Around Rs. 500-600 and you have a headunit that can now play USBs. And not just play them, but play them at excellent sound quality :).
And thats all folks!