BACK UP CAMERA FOR 2012 PRIUS two TOUCH SCREEN- NON NAV

To our1vue:
I should have been more detailed in my response. The orange wire receives all the current (mA) that runs through the camera. It doesn't matter where it comes from (as long as it's from a more positive voltage, 6.5 or 12 volts). The HU just detects the current and activates its video screen. If its a 6 volt camera, the current comes from the white 6.5 volt wire (my circuit is not necessary). My circuit sums the camera 12 volt current to the 6.5 volt current and sends it back to the HU via the orange wire. Thus it fools the HU into detecting all the current that runs through the camera and my circuit.

The trick is that early on in this quest, from reading all the postings, I had erroneously thought that the orange wire was directly connected to ground (0 volts) and that the HU detected current on the 6.5 volt white wire. After some testing a few days ago, I discovered that the orange wire was not connected directly to ground, but appeared to have a function in addition to receiving the camera current. That's why I call it "return" rather than "ground". The current from the 6.5 volt white wire meanwhile, is not detected by the HU. (HU merely supplies 6.5 volts.) It looks like on Start/Power-up the HU turns on the 6.5 volts for 2-3 seconds to allow detection of the camera current on the orange wire and then goes off. Then if the camera was detected, putting in reverse turns the 6.5 volts on, activating the camera to send video to the HU.

 

Thank you for explaining it. It will be a tremendous help for the rest of the folks who will be doing this modification.

Bravo and good work on the Solid-State Switch schematic. The Solid-State Switch will last forever unlike the mechanical relay!

For people who follows this thread, we all learn something new coming from someone who has a new perspective on solving issue as things come up - that is educational and wonderful about this forum because you cannot get this any where before the Internet age.

 

Another new guy here, but it sounds to me like your camera will always have power applied. Not sure if that's good for the camera. Common sense tells me that having a relay of some sort to turn the camera on/off at appropriate times makes the most sense. Dan's approach seems spot-on. Anyone have more to offer?

 

Based on what I know now, I have come up with a circuit that does the work but with parts that are easier to get and are cheaper. Should be about $1.00 plus the circuit board if you decide to use it. Just 2 transistors and 5 resistors. The resistors are all the same value (1.8k, 1/4 watt) as they usually sell them 5 or 10 in a bag. The transistors are the 2n2222 (NPN) and MPS8550 (PNP). Very common, from Frys, Ebay, or probably Radio Shack. I've used 2 resistors in parallel to get the proper drive from the 2N222 to the MPS 8550. It's wired into the 12 volt camera the same way. Diagram and some pics are uploaded.

Built, tested, and installed. Works just like the other. By the way used a small Xacto knife to cut away the insulation at the footwell. Harbor freight also has a cheap soldering iron kit with a small amount of solder. When on sale, its under $10.

I have no comment on Lanlam's installation. Seems like some reverse signal would be needed to properly input to the HU.

 

I did not connect the camera power ground to anything. Apparently it is grounded through the camera video ground. So the camera does not complete it's power circuit until the car is put in reverse. BTW, the camera is still working great.

 

I do recall testing a configuration like this with an external 12 volt supply connected (0 volt side to the orange wire); 12 volts to camera. It did not work. Oh, the mysteries of automotive electronics without a true schematic of how things are wired and how they work.

Submitted for what its worth. I'm sticking with the 2 transistor circuit. Spent enough time on this deal.

 

PriusTime,
Did you ever get your replacement 3.3V camera to see if it would work with 6V ?

 

Alright, get this.... I was messing with the backup camera this weekend. I only installed the RCA Video + and - to the red and black wires and did not attach anything to the white and orange wire, the video works BUT only when I shift to R right after I press the power button to start the car. If I delay in shifting to reverse, the video won't detect. So apparently when I shift to reverse, the Head Unit detected video in the RCA and keeps the video input open. If after the initial period has passed the head unit thinks the camera is not there and will not switch to backup camera mode. Can anyone verify this before they do the complete install? I think that's a lot easier install but just have to shift to reverse to open the circuitry before driving to allow the camera to work.

 

Yes I did receive it, but I just hooked up it using the three wire method described in post #177. Works perfectly. Even if the camera is always on when the car is on, who cares?

I wouldn't want to have to do that workaround to keep the camera working. Hook up the +12V wire to a switched 12V source (most popular is the light blue wire going into rear wiper motor). Works just like a stock camera.

 

I modified my 12v camera by cutting rubber molding on the inline regulator circuit. The circuit consist of surface mounted resistors and capacitors on one side and an AS1117, 3 terminal regulator. There are two 680 ohm resistors on the input side of the regulator that are connected in parallel. I removed them and added 4, 10 ohm surface mounted resistors. I piggy backed 2 resistors on top of the other 2 with a total os 2.5 ohms. The camera now will opeate down to 5.5 volts and maintains 3.3 volts to the camera.

 

Wow! A guy who does surface mount work. This certainly is the most elegant solution. Congrats.

I returned to see what was happening with this thread. I conclude that not all cameras have the same circuitry. Also when I used the external 12 volt supply, its current did not go into the Orange wire but stayed outside the Prius and ran back to the external supply. So that's why it did not work. Some cameras must connect the supply currents to the Vid wires somehow to get it into the HU.

With enough people poking at the sytem, the mysteries do get unwrapped.

I've gone off to work up the Torque application that connects to the OBDII port to monitor the hybrid system operation. Bought the interface (ELM 327). Waiting for it to arrive. Now following the Torque forum.

Dan4500.

 

Wilco Electronics,
What camera did you use and where did you get it ? Thanks

 

It was purchased from eBay. Search for Prius backup cmaera.

Here's the finished product! You can see that I added a white (+6v), a Black (ground) and a red (Video +) wires. The camera only has 3 wires on the 3.3V side and the Camera ground and (Video -) were tied together. I assume that I would tie the black wire to the bkack wire on the HU or do I use the orange wire on the HU?

 

Wilco,
There are lots of cameras on Ebay. I've gone through this entire thread and there seems to be two that frequently come up:
Sun Electronics
Sony CCD Chip Rear View Reverse Backup Camera for Toyota Camry Prius Aurion | eBay

chenwenjiaoeb09
Sony CCD Car Rear View Reverse Camera for Toyota Prius 2012 | eBay

I was just interested to know which one you used. Thanks.

 

I used this one
Sony CCD Toyota Prius Camera Car Rear View Back Up Reverse for GPS DVB T Navi | eBay

 

What's nice about this camera is that mounts directly into the slot when the blank plate is removed.

Here's the question I asked 2 or 3 threads ago;

You can see that I added a white (+6v), a Black (ground) and a red (Video +) wires.
My camera only has 3 wires on the 3.3V side and the Camera ground and (Video -) were tied together. I assume that I would tie the black wire (ground) to the bkack wire on the HU or do I use the orange wire on the HU?

 

Willco, thanks for the link. I'm trying to keep a list of what people have used that worked.

I can't believe how many different people sell this camera in Hong Kong. I wonder if they are all
selling the same camera.

 

The modified regulator circuit works reliably down to 4.5 volts and will probably work fine at 12 volts for short durations. At 6.5 volts it draws 150 ma. I haven't installed it in my 2012 Prius with a non-nav/touch screen radio but I plan to test it at the kick panel and run long wires from there.

 

Willco,
As I read Dan4500's appends, I would think you use the orange wire. That is what Dan figured the HU looked at to see if there was a camera attached.

 

I just installed my modified 6 volt camera and it works. Because it was so close, I wired it to the connector on the headliner. I removed the three plugs that hold the headliner and partially unsnapped the left rear side panel. It gave enough room to reach in and snip the white, red and orange wires. I connected the three camera wires using wire nuts.