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

Here'my question! If the camera is so cheap, I'm sure Toyota only pays a couple of bucks for the camera, why don't they just install it in the Prius One? The Prius One sells for 24k and I don't mind paying a hundred bucks for the added feature. It's already supported by the radio so it doesn't cost Toyota that much more for the safety feature.

The Prius is a hatch back and has a small window with a limited rear view. I already backed into a garbage can at my son's house and broke the rear taillight. That was a $270 mistake. Fortunately I was able to install it myself otherwise it would cost over $400.

That was one reason I joined this forum. We just purchased a 2013 Avalon Hybrid and I noticed there's a Prius chat forum for that model, It's my wife's car and I won't be hacking that any time soon. It already has every feature we need.

 

Willco,
One more question. What was the voltage range the camera worked before you did your mod ?
As for your comment about Toyota, I wonder if they use the backup camera to tempt people into upgrading to
a prius 3 and above. It probably messes up their assembly plan that the US is one of the few places that doesn't require the camera.

 

Before the "mod" it worked reliably down to 7.5 volts. Below that the picture was fuzzy and when the power was removed and applied, the camera wouldn't boot.

 

Willco: How did you get access above the headliner? At first, I intended to connect in there. I popped the 3 pins and the left side panel as well, but the headliner would not come loose enough to let me reach the wires without risking permanent deformation of the headliner. So I did the connection at the footwell. Would help others to know how you got it to drop enough for access. It was tantalizing to see the wires there and unable to reach them without wrecking the headliner. (Used LED flashlight)

As an aside, I broke 2 of the 3 pins. Cost like $2.00 each at the dealer. Parts guy asked how did they break? I told him I was installing my back-up camera. He just smiled and said nothing.

dan4500.

 

There was a small crease but it wasn't noticeable after I snapped it back in place. I used trim tools that purchased from Harbor Freight. The white, red, orange and black wires were together in a separate bundle. After cutting the wires, I was able to pull the bundle towards the back and I didn't have to reach as far to make the connections. I wanted to remove the overhead light but I couldn't see where or how to remove the lense.

 

Yeah, I wanted to get the light loose, but couldn't figure how to do it. Gotta hand it to you. SMT mod to the camera and tie into the roof wires. Most elegant installation, close to a factory install.

 

I did some searching on this forum about how to remove the dome light. It is said there are two indents that you put a small screwdriver in to release the lens. I just looked at my prius and the two indents are on the front side of the lens. I tried to pry off the lens with my finger, but didn't come off. Have to try again when I get home and have a screwdriver. After the lens is off I assume there are screws that hold the bulb housing to the roof of the car ??

 

Just checked out your report. The 2 indents are just to the inside of 2 little tabs that hold the lens on. Use a 1/8 to 3/16 screwdriver blade and press the lens away from the frame towards the outside of the indents. pop the tabs one at a time. The light is held in by 2 tab levers in the light assy towards diagonal corners. You will see the slots that allow for the tabs to be pulled in towards the center. The tabs are almost 1/2 inch wide. This will release the light assembly. I did find that mine was still attached to the head liner by something. It looks like it may be possible to make the connection through the light hole rather than pulling down the headliner.

I did this out of curiousity since I did the installation already to the kick panel but its good to know for possible future additions.

dan4500

 

Willco,

Since I don't have the proper tools for a surface mount modification would it work to just drop down the 6v supplied from the factory wire harness to 3.3v and bypass the inline regulator? Is the function of the regulator just to drop the 12v to 3.3v or is it also involved with the actual video signal? I have to agree with dan4500 your solution is about as OEM as it gets using a $20 aftermarket camera.

 

Don't bypass the camera regulator and feed it with 6 volts. You'll damage it!

Working in the headliner I forgot mention that Harbor Freight has a selection of "long reach" tools that are affordable. Long reach, long nose pliers and wire cutters cost about $15.

The first thing I did with my $20 camera was to cut off the voltage regulator leaving three wires. I "hay wired" a device called a 3.3 volt Zener diode and a 10 ohm resistor. Feeding it with 6.5 volts the voltage was regulated down to 3.3 volts and the camera worked just fine. The circuit is simple and is an alternate solution to modifying the tiny regulator circuit with surface mounted parts. As soon as get time, I have a business to run, I'll upload a diagram. I'm sure Dan4500 knows what I'm talking about and he can draw it to.

 

Here's a simple 3.3 volt regulator circuit

 

Thanks for the info Willco! Using a 3.3v low drop voltage regulator (

LD1117V33) ​

and a couple capacitors to bring down the 6v from the factory harness.

 

Willco,
So you started with your diode/resistor combination that worked. But for extra credit decided to mod the
surface mount voltage regulator ?
Interesting, this thread started out with people using diodes to get their cameras to work, but it wasn't always successful. I wonder if they were using different voltage cameras.

 

I saw the circuit and I also came to the conclusion that it wouldn't work. The diodes were connected backwords and when a diode is connected in reverse, it won't conduct electricity. A Zener diode is different. It's connected in reverse but when the voltage reaches the Zener point, the Zener diode conducts electricity. As the voltage increases, the Zener diode holds voltage constant and draws more current. The 10 ohm resistor limits current and protects the diode from over heating. When the camera is connected, it draws most of the current and very little goes into the diode. I assume the voltage from the HU is constant and won't increase or damage the simple regulator. This will only work when the 12 volt regulator is removed.

 

Willco, are you the guy with the ICM-1024? We're dinosaurs.

I did some random research on Prius Chat. The diode arrangement derives from a posting by "Mik1"on the Prius C forum, "Rearview Camera" thread; page 6. There's a big attachment showing a bunch of install photos A and a schematic with 2 diodes with anodes common connected to the V+ terminal of the camera. One cathode connected to 6.5v and the other to the 12 volt backup lite wire (12volts when in reverse). Too bad but it should have been common cathodes and the anodes connected to the 2 positive voltages. Camera V- connected to Orange wire. There are a lot of correcting posts, including at least one from Mik1, that follow correcting the anode/cathode mix-up. Lots of posters say it works but after the diode mixup is fixed. Lots of readers missed the correction and it was carried through to the Gen III forum/thread.

It supports my guess as to the theory of operation. You still need a compatible camera and there are many variants but a lot of "12 volt" cameras would work with the connection. The 6 volt diode passes the intial test current back to the Orange wire so the HU detects the camera at start-up and is primed for the video signal. When put in reverse, the camera turns on and sends video to the HU and voila. To work, key is a camera that will pass enough current at 6 volts to trigger the detector in the HU. Not all cameras will do that so that explains the less than 100% success. It could be something like CMOS vs CCD as a class or something more subtle.

Your circuitry should work 100% as it truly reproduces the OEM unit. My circuit, though less elegant should also work as it emulates the OEM unit with the operating current from 12 volts. The diode method has the highest possiblity of vague operation.

Cheers to all,
dan4500

 

That's me! I designed the ICM-1024 over 20 years ago and I still sell it.

The simple regulator should work but I'm not sure about the resistor. I don't know the exact 3.3v current draw and I don't know if the HU voltage is 6.5v or 6v. I didn't measure it but if I remember when if first tested the simple regulator I set my bench supply to 6 volts.

I just got my Agilent DSOX3024, 4 ch digital scope back from calibration and if I have time I would like to connect the three wires and measure timings and voltages.

 

I think the CCD cams take 70-100 mA. It looks like your resistor carries 300 mA. Might want to cut it back to 150. 33 ohm should work. less power, too. The orange wire only needs 15 mA to see a camera.

I'm signing off. Gotta fight some legislation here in TX tomorrow.

 

I think the camera draws about 150ma. 33 ohms would drop the voltage too much. At 10 ohms I was dividing the current evenly between the camera and the Zener diode. Both are dissipating about a half a watt. Because I didn't have an oscilloscope at the time I couldn't measure the insantainious current during the camera's boot sequence. It could be higher and 33 or 20 ohms could cause the camera to come up in an unknown state. I tested that using the 15 ohm resistor and dropping voltage to 6.2 volts. That's why I determined that 10 ohms was a better choice. A half a watt in to a 1 watt Zener for a short time won't damage it. Good Luck with your legisation.

 

I also found this diagram

 

Thanks for the diagram! But, I cant seem to find the wire that turns on the Backup Camera all the time.