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Discussion Starter #1
camera voltage at boot?

I added a rear cam to my car and when placing the camera in the back the radio can not see it. If I plug the camera in up front it's ok. I get the voltage from the back reverse lights because the camera +v is only 6 on my head unit (I think it got burned out at some point).

So for a test I turned on the car and quickly thru it in to reverse. All was well. I then did the same thing but waited and it didn't work. So its clear that on boot up it checks for a camera and since I use my own voltage it can not detect and check for a camera.

1) I could give it ignition power instead of reverse power.
2) 24/7 power
3) use the 6 volts I get from the head unit and step that up to 10 or so.

Any ideas?
 

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Discussion Starter #3
Why not tap into the 12v signal wire for the backup lights?
you
I get the voltage from the back reverse lights
me

I'm confused here LOL...

My entire point was that the reverse / backup lights do not power on when the radio boots up and because of that the e7019 thinks there is no camera present. If I quickly go in to reverse (very fast) it will work.
 

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YOU

My entire point was that the reverse / backup lights do not power on when the radio boots up and because of that the e7019 thinks there is no camera present. If I quickly go in to reverse (very fast) it will work.
The reverse/backup lights should not power on when the radio boots up. They should only power on when the ignition is on, and the gear selector is placed in the "reverse" position.

The voltage applied to the reverse lights is +12 volts. If you are only getting +6 volts on your head unit, you have a wiring problem. The +6v is probably not a strong enough voltage to signal the head unit to change modes ( i.e. switch to camera mode on the display).

When you moved the gear selector quickly, the sudden voltage change may have been enough to trigger the mode change, but it will probably not work 100% of the time.

When you correct the wiring and get a full +12volts entering the head unit , you will probably resolve your problem.

JuneBug is saying that you don't need to get the 12volt reverse signal directly at the rear lights, but the same signal is available on the red wire shown in the diagram.
 

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Rickl, from what I've been told, the OEM Toyota backup camera does run on 6 volts. It's powered directly from the OEM head unit. I have no way to verify that.
 

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Discussion Starter #6
JuneBug is saying that you don't need to get the 12volt reverse signal directly at the rear lights, but the same signal is available on the red wire shown in the diagram.
Oh ok, I was going to look for that. I was expecting a more simple answer like "YES" to my "1) I could give it ignition power instead of reverse power." question I guess.

JuneBug , Using the 6 volts does not power up the camera enough, video is flickery. Maybe it is enough on the oem camera.
 

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Rickl, from what I've been told, the OEM Toyota backup camera does run on 6 volts. It's powered directly from the OEM head unit.
According to this post by Pillpusher84, the OEM camera is powered from the head unit, and not connected directly to the backup lights as I would have expected. And according to ulao's first post he is only getting 6 volts from the head unit ( he thought it might be burnt out), so I guess that confirms the OEM camera operates on 6 volts.

JuneBug , Using the 6 volts does not power up the camera enough, video is flickery. Maybe it is enough on the oem camera.
So it seems that the solution is to not use the voltage from the head unit to power the camera, but rather connect directly to the backup lights. As Junebug already mentioned, this circuit is available on the red wire located under the dash.

You will also need to connect the +12v signal from the backup lights into the head unit so that it will switch modes when the gear selector is placed into reverse, but it sounds like you have already done this.
 

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Discussion Starter #8
You will also need to connect the +12v signal from the backup lights into the head unit so that it will switch modes when the gear selector is placed into reverse, but it sounds like you have already done this.
Yeah this one also confuses me? maybe it's because I found a connector in my car that already have rvs,speed,pb sense wires. It was a 5 pin connector I just plugged in. I never needed to add any 12 volts of any kind.

about this 12 volts... When I was in the back I found two wires off the break lights. A 12 volts on for the red brake lights and a 12 volts on when in reverse for the white lights. Call it what you will but the 12 volts for the red lights is commonly referred to as battery power (correct me if I'm wrong but break lights work when the car is off?). That is to say it is on all the time. I think the "ignition power" would be better no? Because having the cam 24/7 would be unwise.

I do appropriate the help with where to get power, but I can figure that part out on my own. So back to my question.

1) I could give it ignition power instead of reverse power.
2) 24/7 power (or call it battery power)
3) use the 6 volts I get from the head unit and step that up to 10 or so.

1, is this not the best option.
2, is this not somewhat asking for problems?
3, this is out.
 

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Call it what you will but the 12 volts for the red lights is commonly referred to as battery power (correct me if I'm wrong but break lights work when the car is off?). That is to say it is on all the time. I think the "ignition power" would be better no? Because having the cam 24/7 would be unwise.
The wire connected to the brake lights will only have +12v when you push on the brake pedal. The wire connected to the reverse lights will only have +12v when the ignition is turned on, and the gear selector is placed into reverse.


1) I could give it ignition power instead of reverse power.
2) 24/7 power (or call it battery power)
3) use the 6 volts I get from the head unit and step that up to 10 or so.
Method #1 will mean your camera is being powered whenever the ignition is turned on, perhaps hours each day. If you connect to the backup lights the camera will only be on a few seconds each day when you are backing up. The increased operating times could reduce the lifespan of the camera.

Method #2 Same reason as #1, but the camera's lifespan will be reduced even further. This method will also cause unneeded battery drain when the alternator is not running.

Method #3 will require you to research and build a circuit to step up the voltage ( a voltage doubler circuit). This will require a lot of time, skill, and money. I don't think it is worth the effort when simply connecting to a different wire is a simple solution.
 

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Discussion Starter #10
Agree with what you said in method one but if you read the first post I made, that does not work because the radio gets confused. For some reason the radio does not see a camera unless it is powered on.

So just re recap a bit here.

Your words - "The wire connected to the reverse lights will only have +12v when the ignition is turned on, and the gear selector is placed into reverse."
This is what I have been saying and is true. You will get power only when both are true not just ignition being on.

problem:
Turn on car
radio comes on
radio looks for camera
car is not in revers and the radio sees no camera (how can it, there is no power to it)
no camera functionality.


fix Proof of issue.
Turn on car
put in revers immediately.
radio comes on
radio looks for camera
car is in revers sees camera
camera has functionality.

So the issue is that I need power to the camera when the radio first comes on.

To fix the issue I have 2 options that are good solutions, one better then the other.

1) Use ignition power - downside ,camera always on when car is on.
2) Use a relay to scene the 6 volts, then apply ignition power. Very simple circuit. Actually, there is no circuit at all, it's just a relay.
 

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It appears that your head unit operates differently than any aftermarket head I am familiar with. Every head unit I have worked with, will switch to camera mode automatically when it receives +12v on the REVERSE input. This +12v supply is normally obtained from the backup light circuit. The composite analog video signal from the camera (normally a yellow RCA phone plug) is connected to the head units VID-IN connection. These units do not detect the presence of a camera during boot-up.

So, since I don't know anything about the OEM head unit, I will assume what you say to be true, and offer you some ideas based on theory alone.

Since the subject of your thread was "Camera Resistance" I assume you think the head unit is detecting current flowing into the camera, from the 6 volt output, to determine if a camera is installed. If that is how it detects the camera is installed , then using any other voltage source will not work. As your thread subject stated, you would have to determine the current draw of the OEM camera, and place a dummy resistor across the 6volt output to simulate the presence of a camera.

Or do you think the head unit is looking for a 1volt P-P signal (nominal comp video voltage) on the VID-IN connection, to determine if a camera is present?

I guess you can quickly determine which method is being used by temporarily connecting the camera to the battery.

I still don't know what you meant when you said " If I plug the camera in up front it's ok.". Is there a front video-in jack on the head unit, or do you mean you powered the camera from a voltage source at the front of the car?. In other words, have you already performed the test in my last paragraph.

By the way, good idea about using the relay to convert 6volts to 12volts. I was considering an electronic circuit in my head.
 

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Discussion Starter #12
It appears that your head unit operates differently than any aftermarket head I am familiar with.
It's the factory e7019


it was "Camera Resistance" but I changed it, I guess the forum does not update it properly.

you think the head unit is looking for a 1volt P-P signal (nominal comp video voltage) on the VID-IN connection, to determine if a camera is present?
I do, I was thinking of adding a simple pull up resister but didn't want to mess with the camera circuit.

I guess you can quickly determine which method is being used by temporarily connecting the camera to the battery.
, Sorry for not including that. This does work by use of the cigarette lighter. This was what I meant by plugging it in up front. That was not very clear, sorry... I meant not using the cable I ran to the back and just plugging the camera in up front directly and using a cigarette lighter to power it on.

Well the relay does not convert, it just "relays" :) but yeah, I'm a EE, so when it comes to working with wires and electronics I'm good, it's just that I have little automotive experience. So I have a tendency to think differently and I know that can be difficult. terms, names ,etc..

but yeah, so in the simplest terms (and my fault for assuming you checked my previous posts.) I'm just adding to a base rav4. It had nothing... I added a camera and a radio. I found the plugs. I looked and looked and looked for the camera wires ( I figure the car already had this ran ) and gave up. Then I decided to run my own wires and found this oem radio sends 6 volts out but the camera needed 12. Now I see the radio looks for a video signal on boot up. I should have just got the oem camera for price*80 $ more...

thx for the help, its hard to get that around here at times and certain topics...
 

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Well the relay does not convert, it just "relays" :) but yeah, I'm a EE, so when it comes to working with wires and electronics I'm good, it's just that I have little automotive experience. So I have a tendency to think differently and I know that can be difficult. terms, names ,etc..
I understand things a little clearer now. I was initially confused by a couple of things you said, probably becuase I had not read any of your other threads (I have just read them now). Your statement "My entire point was that the reverse / backup lights do not power on when the radio boots up" made me think that you expected the radio to turn on the backup lights. And then when you said the camera works when using 12volts from the front of the car, but not 12volts from the backup lights, made me assume you must have a wiring error to the backup lights.

As you made more posts it became more obvious that you knew what you were talking about. Since you are an EE I am also surprised that you didn't come up with a more complicated way to get 12volts from a 6volt signal. A relay is way too simple for an EE to even consider.

I still think it is odd that the head unit checks for a video signal at boot-up. I think it should just switch to the "Video In" screen anytime it sees the 12 volt Reverse signal. By powering the camera all the time, it may cause some reduction in life expectancy.

Knowing what I know now, I think the relay solution is the best.
 

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Discussion Starter #14
A relay is way too simple for an EE to even consider.
To be honest I expected a plug and play here. It's not like any of this is new.


I still think it is odd that the head unit checks for a video signal at boot-up. I think it should just switch to the "Video In" screen anytime it sees the 12 volt Reverse signal. By powering the camera all the time, it may cause some reduction in life expectancy.
Agreed on all points here.


I'll wire up the relay when I get home and all should be well.
 

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Discussion Starter #15
The relay didn't really work out well, the radio still had issues detecting the camera every time. I also added a wheeling diode and it still tripped a fuse. I'm not sure what kind of Sorcery Toyota did here but... I got a 4runner cam and mapped out the wires and it worked fine. Better then buying the $500 rav4 cam, sheesh. Most all Toyota cams opera on 6 volts.

Still, I would have preferred using the existing wiring, I do not believe it's not there somewhere (as pointed out on my other post) but running my own wires got it done.
 
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