Need Schematic For An ELP Camera

Thread Starter

MrAl

Joined Jun 17, 2014
7,795
Hello there,

I need a schematic for an ELP 2.0MP web cam.
I need to disable the IR LED's on the pc board.

Disconnecting the power connector to the LED board turns them off, but it also prevents the camera from switching into night mode. I need it to be able to switch to night mode.
The problem is that only one sensor is used to sense day or night, and it happens to be mounted on the LED board, so powering the board off also disables the night mode.
There is another thin wire that comes off the LED board but that wire is for the camera to sense the day or night modes, so pulling that connector out also disables the night mode.

There are 5 tiny transistor on the board, along with multiple SMD resistors and of course a lot of IR LEDs.
The LEDs can not be taped up or covered up because they generate heat. They have to have normal air flow.
I've considered a metal or plastic box to house the LED's in but then the sensor is not exposed in order to sense day or night. I may be able to make a pinhole so the sensor can get light, but i really dont want to have to go that route. If i had the schematic i would know what to do right away.
There is apparently no way to trace out the circuit because the board is a dark color and i think it is a multi layer pc board.
I also dont want to paint the LEDs because i may want to use them at a later date.

Any ideas?
 

Thread Starter

MrAl

Joined Jun 17, 2014
7,795
Hello again,

I am not surprised that there were no replies yet. I looked and searched and could not find anything related to this other than sales of the item itself.

After thinking about it some more, i came to the conclusion that without a schematic the wiring of the IR board is just too complicated to guess about so modifying the board probably is not an option without a schematic, and it appears that the sensor is tied to the IR LEDs as well as the day/night switching mechanism (which switches a filter in behind the lens for day operation) so messing with the board could disable the night vision by mistake.

This led me to think that the only way to do this is to disconnect the pc board and develop an entirely new board that has a sensor that only operates the day/night filter switch mechanism and removes all the IR LEDs.
After looking at the board, it looks like the sensor works with one or two transistors to operate the day/night switch mechanism so i figure that a new sensor plus one or two transistors (and the included 5v power source and wire to the switch mechanism) will allow proper operation of the mechanism without having the LEDs simply because they will not be part of the camera anymore.

To determine the required signal to the switch mechanism i should only have to make a couple DC voltage measurements. One to make sure which wire is power and which ground, and what logic levels the day/night activation wire requires. I have a feeling that wrie works with anything from 2.5v to 12v, but since it is USB it is most likely 5v to activate and 0v to deactivate.
The measurement wont be easy because it involves some very very small test points on the pc board. This will require a straight pin and some alligator jumper leads.

Wish me luck i would hate to ruin this camera.
 

Thread Starter

MrAl

Joined Jun 17, 2014
7,795
Hello,

What is the partnumber?
Here is a link for the setup of the ELP-IP1881:
https://www.instructables.com/id/Setting-Up-the-ELP-IP1881-Camera/

Is there a setting in the software to disable the IR leds?

Bertus
Hi,

Thanks for the reply.

The only model number i have is ELP 2.0MP.

There is no setup for this cam, it is a very simple USB wired web cam it just has night vision with it which sets it apart from a 'regular' web cam that just does daylight.

There is also no setting for the IR LEDs. The only settings are for regular stuff like brightness, contrast, gamma, saturation, hue, sharpness, exposure, and there is also a 'gain' control but playing with that makes the picture very grainy.
There is no control for the LED's unfortunately and the only wiring to the LED board is power, ground, and an output that controls the night vision switched filter (for daylight operation it switches in an IR filter that filters out most of the IR light but at night it switches that filter out so it can detect IR light, and the filter is a physical filter that physically moves in behind the lens just before the CMOS image sensor for daylight operation).
It is not the best camera in the world (for example no automatic iris control) but it has night vision so it makes it more useful as a security cam.
The reason for wanting to 'turn off' the IR LEDs is because i already have an IR light source that illuminates the area at night and the cam has to be mounted inside a window, and when the IR LEDs turn on some of the light reflects off of the glass and back into the camera and any slight smug on the window shows up in the picture like a big cloud.

Talking about this with you though made me realize there is another solution if i cant get a schematic (other than creating a new dumbed down pc board). That is, extend the three wires that go from the camera board to the IR board, and that would mean i could place the IR board in a location father away from the cam, possibly very far away, although the sensor on the IR board still has to be able to detect the daylight light in order to know when to switch from day to night or night to day operation.
 
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Thread Starter

MrAl

Joined Jun 17, 2014
7,795
Hello again,

I found a part number of the IR board itself.
ELP-IR5V24LED

and on the camera board:
ELP-USBFHD05MT.RL36
although that '3' may be a different number or letter as it is partly worn off, although that full number shows up on sales sites for the camera.

I could not find a datasheet nor a schematic but i did take some measurements and i found out that the input to the cam board requires either 2.0v or ground 0v to operate and that it is a very high impedance input so probably a CMOS logic input.
This means that even a 10k (light) LDR would activate it in concert with say a 10k impedance resistive voltage divider. A pot somewhere would make the day/night threshold adjustable.
 
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Thread Starter

MrAl

Joined Jun 17, 2014
7,795
Can't find much on this. You might try contacting the supplier for a full schematic: http://www.webcamerausb.com/contact-us-ezp-2.html
Otherwise, the CMOS sensor is an OV2710. You can find the full datasheet for it here (with a reference schematic for it)
https://datasheetspdf.com/pdf-file/768334/OmniVision/OV2710/1
Maybe that will help with mode changes to the sensor. ELP also offers an SDK for this cam.
Hopefully this helps.
Hi,

The datasheet doesnt really help for that.
I tried downloading the SDK but it does not work. The zip files had nothing in it, and the Help file does not show anything except the table of contents...no actual information.
 

Thread Starter

MrAl

Joined Jun 17, 2014
7,795
Hello again,

Last night i did a simple experiment.
Using a 22k and 33k resistors to make a simple voltage divider, i got the 5v USB supply voltage down to 2.0v. Placing a 10k nominal resistance light dependent resistor in parallel to the 22k, when there is no light on the LDR the voltage is close to 2.0 volts, and when there is some light on the LDR the voltage goes down.
That 2.0v is supplied to the camera board, day/night input, and when it is 2.0v it switch to night vision. So when the LDR resistance is high (like 1 megohms) that means little light and the camear switches into night mode, and when the light comes back it switches back to daytime mode.
So this seems to be the simplest solution as it works like this.
Now all that is left is just to solder everything together and mount it some way.

Oh BTW the input impedance of the camera day/night input looks like it is more like 20k.
That would mean that the required night mode activation voltage level could be lower than 2.0 volts.
 
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dreamsofhabit

Joined Sep 11, 2020
16
That would mean that the required night mode activation voltage level could be lower than 2.0 volts.
Based on the system power configuration (1.8V or 2.8V/3.3V for I/O power, using external DVDD or internal DVDD, the power up sequence will differ. If 1.8V is used for I/O power, using the internal DVDD is preferred. If 2.8V/3.3V is used for I/O power, due to a high voltage drop at the internal DVDD regulator, there is a potential heat issue. Hence, for a 2.8V/3.3V power system, OmniVision recommends using an external DVDD source. Due to the higher power down current when using an external DVDD source, OmniVision strongly recommends cutting off all powers, including the external DVDD, AVDD and DOVDD when the sensor is not in use in the case of 2.8V/3.3V I/O and external DVDD.
Maybe 1.8v? I'm no expert here, just thought that might be helpful? idk. Good job though!
 
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