My Roomba Doesn't Want to Carry a Load

[DeafPaul]

500 series (pet version from Costco)

Whenever a heavy-ishload (25-30 lbs) is put on it, it does not want to carry it in a straight line. It will start turning every which way as if it's trying to dislodge itself, and after 10-15 seconds, it will stop and red lights will flash. I assume it also says something, but I'm deaf so I have no idea what it's saying.

At first I thought that the main wheels were bottoming out and causing drag, or at least setting off a sensor that told the Roomba was stuck, or getting stuck.

So I removed the wheels, cut out some heavy duty foam inserts and put them between the wheel and the fender walls to keep the suspension from compressing. Big mistake as it sat several inches too high and would not even go. I then realized that when it was the right side up without the foam inserts, the wheels were indeed "bottomed out" therefore it's not the wheels that needed to be raised, or held open. Must be a sensor or something else completely that needs to be messed with to get it to carry a load without freaking out. I removed the inserts and it's rolling around fine now, but still won't carry a load.

Any ideas?

-Paul

[vic7767]

There are wheel up/down sensors as well as motor current sensors that will basically prevent the Roomba from performing that extra load duty you are attempting.

[mfortuna]

25 to 30 lbs is a lot of weight. What are you trying to carry? I think you are simply overloading the roomba's motors.

[DeafPaul]

How does one go about disabling those sensors and what would the impact be on it's ability to continue to perform it's primary job of cleaning when unloaded?

It's not what I'm putting on it, it's what my triplets have been doing with it. The like to hop aboard (seated most of the time) and try to get it to give rides. *dons flame suit*

I think the motors are capable, especially on hard wood floors. It has no problems spinning/moving with a kid for short periods of time before balking. I checked youtube for this and saw a bigger/heavier kid than mine ride along just fine (not sure what series) on a hard floor. We have hard and carpet, and mine does the same "Balk and try to spin it's way out" whether on carpet or a hard surface which leads me to believe it's sensor/suspension related.

-Paul

[TechGuy]

iRobot puts the limit on the current draw from the motors to protect the motor and the driving transistors. It you disable the current sensing circuit, you are running the risk of killing the H-bridge transistors without the heat sink installed.

Adding heat sink to the H-bridge transistor is easy. There is not much space between them for the heat sink. But doable. Disable the current sensing is more difficult as it is controlled by firmware. One may drive the Roomba using SCI interface.

[Koontzy]

yup rootooth with the full mode should do the trick

[vic7767]

Putting a youngster on top of a Roomba with all its sensors disabled is not a solution to consider.

[mfortuna]

Putting a youngster on top of a Roomba with all its sensors disabled is not a solution to consider.

Especially if you have stairs!

It may seem cute but anything with moving parts is not a good thing to expose toddlers to. Just my opinion!

[TechGuy]

I agree with vic7767.

As a parent, don't leave your kid on Roomba without watching them while Roomba is moving. This is same as leaving a kid on a tricycle and making sure that the kid does not driving it to the middle of a highway.

[DeafPaul]

I'm glad I donned my flame suit.

TechGuy - it sounds like you are implying that the Roomba is shutting down due to excessive current draw. Is that the only technical problem here?

-Paul

[boomer729]

Even if you can keep the motors from shutting down you will likely strip those little plastic gears.

[DeafPaul]

Allright - thanks for the response guys. Doesn't look like the Roomba is going to be able to be used for more than 10 or so seconds at a time by my kids, and not to transverse any distances. I do wonder how these bigger/heavier kids manage to ride their Roombas further and with less shutting down than mine does. Guess the pet version from Costco isn't the better one to have.

-Paul

[mfortuna]

The create, which has similar wheel motors and circuits has a maximum rated weight of 5lbs. And it starts out lighter, having no brush deck or vacuum motor.
http://homesupport.irobot.com/app/answe ... -create%3F