How would you connect a camera robot for rainwater drain inspection?

Hi,

I have a problem with one of my rainwater drains and I want to get a good look inside and of course I’d love to use the parts I have.

I want to build a very simple robot that can pull the camera into the tube using an Arduino (plus DC motor, H-bridge, a stepper for camera movement, some LEDs for light). This should be controlled by a laptop which is also needed to show the live footage from the camera.

The tube I want to examine is 100mm in diameter and max. 8 metres long - most probably I don’t need to go in the full length. It’s a metal tube so I guess wireless won’t be a good option.

And here is where I wonder how I should do the cabling: I think the robot could be connected with a long USB cable (long means around 6m) and the camera is a USB device. The motors and the LEDs of the robot may require a powered USB hub (the motor draws 120mA with no load except the attached gears).
The easiest solution I think is using two long USB cables and plug them to a powered USB hub together with the notebook. But then the robot has to pull two cables.
I thought about packing a USB hub onto the robot but all I could find are rather big and the plugs in a right angle to the length of the body which makes them impractical for my needs. The maximum diameter is 100mm and there may be less space the more I go into the tube so every millimetre counts.

Do you have any idea how I can achieve that with only one - possibly custom made - cable?
Is wireless ruled out if there is only one 90° turn at the beginning? There may be a line of sight to the moving robot beyond this turn although I don’t know for sure.

Wireless is out in a metal tube, and most likely, so is a motor powered by USB. You will probably have difficulty with long USB cables as well.

A motor that draws 120 mA no load will probably draw over 1 Ampere (the stall current) every time it starts up. Better to have some AA batteries on board.

What kind of drain? Do you have access along its length, both ends, or is it something underground?

It's only 8 meters, and if you're looking for a blockage, you're likely going to poke it with a drain snake anyway to fix it. Meaning, you don't need to see it to fix it. And if you do want to see it, just attach the cam to the drain snake and run a usb extension. 8 meters will be fine.

A robot is overkill and you risk clogging the drain with a malfunctioning robot.

INTP: What kind of drain? Do you have access along its length, both ends, or is it something underground?

It's a rainwater drain and it runs under the house into some bigger tube for all the drains on the opposite side of the house so there is only one side which I can access without digging.

INTP: It's only 8 meters, and if you're looking for a blockage, you're likely going to poke it with a drain snake anyway to fix it. Meaning, you don't need to see it to fix it. And if you do want to see it, just attach the cam to the drain snake and run a usb extension. 8 meters will be fine.

A robot is overkill and you risk clogging the drain with a malfunctioning robot.

Well, we already tried to clean it "blindly" without success. As there was some construction going on I'd really like to see what blocks the water.

And I admit that a robot would add some fun to the otherwise boring project ;)

Hi.
As its a one off attempt, just to check your drain, check with your local water authority, they may have a service that will do that for you.
Drain cameras do exist, the units I have serviced are not driven like a robot, but drain snake type, so you can pull them back.
They have LED optical and IR sources so you can see in the dark.

Your robot will need to have lights

The least hardware you have hanging of the robot the better, hence the snake form factor.

Tom… :slight_smile:

Endoscopic cameras with LEDs are <$10 on ebay via slowboat. Still considerably expensive considering the pennies the tiny CMOS cameras cost raw, but in a neat package ready to stream to a PC via USB interface is convenient.