LibreRVAC: Severin RB7025, Dirt Devil Spider (M607)

This page needs a lot of tidying up.

Severin RB7025 and Dirt Devil Spider (M607) are identical[1].

There is also a chance that Dirt Devil Libero (M606) is quite similar.

In terms of custom firmware, these are the most hopeless vacuum cleaners that could ever be found.

Description

Let's list some of the problems:

No encoders at all. That is, you can't measure the distance, you cannot even go in a straight line. Hopeless!
No overcurrent protection!
Bag detection is not wired to the microcontroller. All it does is just light up an LED. In other words, you can start it without the bag and the microcontroller will not notice.
Bottom sensors and bumper are connected to the same pin. You cannot know whether you are falling or you have hit the wall.
No buttons. Sure, we can use bumper for user interaction, but…
There is only one switch on the bumper.

Basically, that's enough to understand that any further reverse-engineering is a waste of time. But here is a pinout anyway:

Pinout

Pin	Type	Function	pullup/pulldown	active	Comment
1	out	green LED		high
2	in	bumper or sensor	+5V	low
3	out	buzzer			requires PWM, also 1-pin connector on the board is connected here
4	power	VDD
5	in	battery low	+5V
6	out	vacuum and side brushes		high
7	in	top lid
8	out	left wheel forward		high
9	out	left wheel back		high
10	?	battery charged			probably input, when charging “high” means “charged”
11	power	VSS
12	out	right wheel back		high
13	out	right wheel forward		high
14	out	red led			also connected to unpopulated port, no idea what these port do (both are connected together)

Some “pullup/pulldown” and “active” cells are empty. Filling those has no practical value because nobody is going to attempt to reflash it anyway (and if somebody does, you will probably figure it out yourself).

Photos:

https://files.progarm.org/severin.zip

Comments:

Port 10 is likely output, since pulling it HIGH stops charging. The charging cycle doesn't stop by itself.

I guess ports 5 (batt low) and 14 (red led) could be shorted, so that low battery means the corresponding led turns on. On the other hand, keeping pin 5 connected to a microprocessor means you can start the return-home-procedure.

-- Thijsmans 2018-06-13 20:37 UTC

I think you are overly harsh. Sure, the Dirt Devil is cheap and basic, but if anything it makes it more suitable to hack. I replaced its chip with a WEMOS D1-D2 to give it wifi (http://paijmans.net/Dirtdevil) and the next step will be a LOLIN32 so I can add IR capabilities, some more bumperswitches and use all the inputs... wish me luck!

-- paai 2018-10-01 07:52 UTC

paai, I agree with you! This was written in context of this project, with the idea of creating a somewhat universal solution for many robotic vacuum cleaners. If the goal is to have a hackable robot platform, then perhaps it is indeed suitable. Thank you for your comment!

-- AlexDaniel 2018-10-02 20:55 UTC