Roomba S9+ Bumper Hall Sensor - Error 9 / 31

[LazyRoomba]

Hello,

I have got a Roomba S9+ with an error 31. I found that he entire bumper mechanism is very sticky / stiff, and the hall effect sensors to be too unreliable. I'm at a stage where I need to wire up a switch in place of the hall sensor.

The Vin of the hall effect is 3.3 volts, and the Vout is 1volt. With a magnet under, it drops to 0.6 volts. In order to have the tactile switch (that I stole of my Neato's bumper), I need help with sorting out a voltage divider. I have no experience with one, but I know one is needed. The switches from the Neato are of a normally open type.

Currently, Roomba's left bumper was slamming into things, and climbing walls before error 31. Now that I have removed three of the hall sensors, no voltage is going to the Vout (1v), so error 9 is now been output. I've attached a couple of photos of the bot.

The hall effect sensor is marked 1m12, datasheet https://www.ti.com/lit/ds/symlink/drv5053.pdf

J1 is Vin, J2 is Vout, J3 is common GND, shared with the other three hall sensors.

[LazyRoomba]

Just a quick update.

I've reinstalled the hall sensors, just to get the Vout voltage, as I don't have any resistors. I then attached the bumper NO (Normally Open) switch onto the Vout and ground, and this works. When the swich is triggered, it pulls Vout low, and the robot reacts with the bumper collision. This is how I have the switches wired:

On an interesting note, the robot was about to do error 9, until I shoved a neodymium magnet on the left side of the bumper. After taping this magnet to the bumper, the robot performed with no errors (No 9 or 31). Interesting to see.

I will need to open up the bumper again anyhow, but I think I shoved the hall sensor in that corner, dangling. I wonder if it caused the original error 31..

One last thing, the center left hall effect sensor is still installed and been used. The center right, right and left hall sensors have had the magnets removed and are running the switches stolen from my Neato XV Pro.

[LazyRoomba]

Another update. Error 9 came back again. I powered on the roomba with the bumper plugged in, but sat on the table. I measured the voltages on the hall sensors, and noticed that the Vin keeps dropping to 1.1 volts from 3.3 volts. It looks like something isn't right with this tiny board. I've yet to trace where the 3.3 supply is, as the Vin for the entire board is battery voltage.

Edit:

The 3.3 voltage regulator is sat here:

Is is marked G3P, or AP2112. The Vin of the IC is connected to the Vin of the board, which is battery voltage.

[LazyRoomba]

Why what do you know... The data wire from the main board to the bumper board. Guess what I found? When I bend the wire, the voltage on the bumper board drop to 1.2 volts, then goes back to 5 volts when bent back. I think I may have found the intermittent error 9 fault, and possible error 31.



Also to note, the Roomba S9 will give error 9 when the bumper board is not installed.

Edit:
A closer look at this cable shows chaffing where it bends over the top of the main board, with visible damage to the wires.

I will cut and extend these wires to better route them, and test if this solves the issue.

[LazyRoomba]

Just wanted to give a quick update. I'm still working on the bot, and I know exactly the issue and what is causing said error.

I've got quite a lengthy post to write up and images to edit for explanation. The recent discovery I found got the bot working by disabling one of the edge hall effect sensors. Again, I'll need to do more testing, and write up my progress.

[metroid311]

Hi, I've been following your post and waiting for new info. any updates on your work?

[LazyRoomba]

Hi, I've been following your post and waiting for new info. any updates on your work?

Hello,

I've been having issues with the inlaws, so I've not been able to do required testing. I can say however, the Roomba is pretty reliable at this time.