Fraggboy wrote:Gordon wrote:In such a case, you might try running Scooba, say at night, when you could then switch off interior lighting to see how it responds.
Great! I will do the test this weekend. How will the Scooba react to it pitch black? Should I see the strange behavior during the drying cycle, or after the 5 minutes? Will it drive around erractically, or what kind of behavior should I be looking for and when?
Good Qs, for which I have no experienced answers! Here are some guidelines (which suggest the test may not go off as quick as we would like).
The light-sensor's purpose is to prevent the robot from quitting--presumably switching its power OFF-- while under, e.g., a bed after having depleted all battery-charge. But, the bot also has a job to do in that darkened space, so we can't expect it to simply respond to the dim-condition by immediately racing out from under the bed.
With *that* in mind, I foresee the need to run a cleaning mission (maybe, one-plus) long enough in a lighted space to use up a lot of charge, but not trigger a battery-depleted halt.
Doing that, will permit you to do other things while waiting for the proper condition. For you to *know* when that condition is imminent, one or more trial / timed cleaning sessions may have to be done in advance. (Sounding more like work, now, eh?)
Then, with Scooba chugging away, and w/in minutes of a dead-battery-halt, you switch off the room lighting, to put Scooba in the dark.
Scooba's firmware will have been sampling battery-voltage, and at some voltage level it will "set a flag", and begin watching for a reduction in ambient light level. {I'm making this up, you must realize, since very few people in the Universe know what the firmware does!}
I think we must assume the worst-case "lost in the dark" situation; and that would be the case in which the bot entered the dark area without 'knowing' it should be concerned about loss of light (in your test, this would be represented by switching lights off too soon), did some cleaning under there--enough random 'navigation' that it could not retain an internal bread-crumb trail to permit back-tracking--and *then* the battery-low state and lights-off state occurred.
When the MCU (already being aware of low-battery) learns *lighting has been lost*, it halts squirting of cleaning-solution, shuts OFF power to its wheels, then it calls on its emergency "find the light" routine.
What can it possibly do to get back to the light? I see two possible actions--others may see more.
1) Scooba may spin in place, doing a full-circle, body-centered rotation. Thanks to Howard, we know the MCU will respond to at least three light-levels (Self-Tests show that). *Probably* the light-sensor's circuit provides an analog signal to the MCU, hence, it *may* be capable of responding to all levels. IF so, Scooba will be watching for any increase in illumination as it does that full-circle rotation, and log the wheel-turns count it took to reach that pointing.
Then, its just a matter of rotating around to that position, and strike out on a vector to see if light-intensity increases. If no increase, then operations would default to the next process.
2) Having logged some room-size data before going under the example bed, and (*possibly*) 'knowing' the dimensions of the largest bed it may ever be stuck under, Scooba may try straight-line excursions of particular length(s). interspersed with right-angle and/or 180-deg turns, in an attempt to see light.
When it sees light, it travels toward it, and ultimately halt itself and sound the job-ended tones.
Therefore, Fraggboy, when you (in the dark-room) hear motors switch off, then wheels start driving (the Vac/Blower motor may be left on for a while, or not), you should be prepared to turn on a remote (like in a hall) light, so Scooba has a target to seek.
Well, sorry it took me so many words to get to the end! I always find that I write more words when I talk about something I know nothing about!
I just caught a peek at THX's one-liner! I wonder if its really that simple(?). THX: Have you run a dark-test on Scooba?
Whats worse is it has a full tank of dirty water on it and u have crawl in and get it out!!! I've been using Scooba to clean my bedrooms and while doing so, i usually close the bedroom doors so that it can clean the area behind the doors as well. There was once it finished the cleaning cycle right behind the door. Imagine that... u have to push hard while opening the door to force Scooba to move sideways to get into the room 
