Cliff sensor error on door mat...ALWAYS

[crypted]

For some reason, this Roomba can go over one identical door mat at one of our doors but it cannot do the same for the other. I took this offending door mat outside and beat it to ensure most of the dust and particles were off of it. The problem persists.

Basically, the Roomba 530 will get on top of it partially and give an error beep. The message played says to clean the cliff sensors. I cleaned them with a dry cloth and with a can of air. I placed the Roomba near the door mat. As soon as it hit the door mat, same error. I repeated the cleaning and placed it directly on the rug. This time, it wouldn't start up and would just repeat the cliff sensor message.

Any thoughts on what causes this to occur on one of the two identical door mats?

[vic7767]

Once the cliff sensor IR can no longer receive the IR signal from the transmitter it will respond with the cliff sensor error. Dark colors (like flat black) cause this. Here is what iRobot has to say:

[crypted]

Yeah, I considered that. But seeing it work on an identical door mat at our other door without problem made me doubt that as the underlying cause.

This leads me to now ask a business-related question. In your Multiple Mod Mania, what does "Upgrade of both IR devices in both Bumper sensors" handle? Would it make these sensors more powerful to handle such obstructions or issues?

[vic7767]

There is a common component failure that causes the Roomba to generate the "9 beep error" which is a Bumper sensor error and should not be confused with the Cliff sensor error. The Bumper sensor is comprised of an IR transmitter and receiver and is somewhat similar in function but the hardware is different. The Bumper sensors seem to have a high failure rate that is resolved by replacing both devices with a better quality pair.

The Cliff sensor failure with dark colors is entirely different in that it is not a component failure. The sensors are operating and depending upon the way they are mounted within their holders, and the amount of additional debris that may have accumulated on the lenses and other surfaces nearby will cause the failures your Roomba reports. Not to mention the variables of each sensor component during manufacture.

[Gordon]

... seeing it work on an identical door mat at our other door without problem made me doubt that as the underlying cause. ...

The real 'trickery' going on here is that the Cliffs' are responding to reflected (scattered, to a great extent) radiance in a part of the electromagnetic spectrum (the infrared region that technically starts beyond the visual 'reds') that your eyes cannot! IOW, the colors that your eyes see are not those that a Cliff sensor emits as a series of timed pulses.

[mfortuna]

We have brown rugs with a wide black border. Sometimes our roomba red sees the border, and retreats as if there is a cliff. Other times the robot would get on the border and stop believing it was in space. It would also pass over the border and get trapped on the rug, resulting a very clean rug.

I think the speed of the approach and maybe even angle determines how the robot will respond too a black rug. Bottom line it is not supposed to work on black rugs.

[Roombascoobatastic]

I have the same black mats and my roomba cleans them without issue. The scoobas do attack them so I have to fold the mat over when scooba'ing.