Matrix MOW800

Sascha

Administrator
Staff member
This year I have started a new project. I bought a Matrix MOW800 on Ebay, not knowing that it has brushless motors.
So I took out the old mainboard, but unfortunately this mower is too small for an Ardumower board, so I had to get something else.

I worked a bit with KiCad and created a simple PCB for the Ardumower. The PCB consists of two parts, the main PCB for an Arduino DUE and the sensors and a power/charging PCB.
I have already posted the board in another article.

Since the mower has brushless motors, I first ordered the new Motor Drivers from the Ardumower Shop to do some tests with them.
Unfortunately, they blew up on me during the first test.
Now I have some China brushless drivers that work with the motors, at least with a simple test code.
AzuritBer with perimeter loop will be used as software later.

A few photos will follow.
 
That was the First Stadt in the legt Side. In the right Side a Ardumower PCB
 

Attachments

  • IMG_20210426_170108.jpg
    IMG_20210426_170108.jpg
    1.2 MB · Views: 36
  • IMG_20210515_103829.jpg
    IMG_20210515_103829.jpg
    823.6 KB · Views: 28
Since it's not snowing or raining today, I took the Matrix into the garden and let it drive for half an hour.
The settings seem to be ok now and it is running its course in the garden.
A few fine adjustments are certainly necessary, but only time will tell.

The perimeter tracking doesn't work so well yet, it keeps turning away from the wire and stops, but this is probably due to the high grass at the edge, where it needs more power to drive, so I'll have to test it a bit more when the edge is mown.
When it has found the charging station, charging also works.

And now i'm waiting for the last Motordriver for the cutting Motor.

Unfortunately, I didn't make a video, but I will next time.
 
It's actually 16 Hours and 8 charging test on my MI-632 .
For tracking you need to set the max signal correctly into setting perimeter according the real value when mower is near perimeter.
 
Just to understand.
I loaded a programm in the teensy on december but I don't know if this version is ok or if I should use an updated one ? on the Teensy, the bridge is already in place; when should I open this bridge ? Can I do it directly and do updates later ? same question for the PCB battery; when and why... ? I'm learning on doing... thanks.
I hope to be finished with connections this week and to start step by step.
 
Last edited:
Bernard has made some changes since then, so download the latest version.
You can disconnect the trace, but if you want to load something on the Teensy, you have to power the PCB as well.
And please first power the PCB without Tennsy and ESP32 and set the DC/DC to 5V
 
I finally got the driver for the mower motor, but I'm not happy with it at all.
It is very loud and gets hot quickly.
I think I need to do some more testing to see if the cables are in the right order.

@LaurentS , do you have a video of the cutter motor turning?
 
Today is my lucky day or what should i call it?
 

Attachments

  • 16502117097715046470359564091993.jpg
    16502117097715046470359564091993.jpg
    996.4 KB · Views: 28
Power on and then magic smoke.
It may be that there was a small copper strand on it from the desoldering that i din't see, the IRF and Teensy are also broken again. Today is my lucky day
 
Ok now have everything running again, had to change all the INA, the GY 521 and the Teensy.
Expensive fun...

Bernard, when I start the MOW engine now, I see the power in watts goes over 100 and the engine switches off again immediately.
Min PWM: 70
Max PWM: 120
Max Watt: 60

@Bernard
Wasn't there a delay so that it only starts measuring the current after a few seconds? I can't explain why the motor needs so much wattage at the beginning.
Or can something be wrong with the INA? When the motor is off, it still shows 2.85 watts.
 
Last edited:
My mower is in charging station, I take a look tomorrow , but it's strange , normally mow motor accelerate slowly on startup, so no extreme power.

For INA226 the issue is in the R010 resistor value are not always perfect and the result is not accurate, but 100 W is not OK for a small mower.
Try to invert with the INA226 for battery to see if the error is always here.
 
It didn't show as much before either, it was just over 60W with more max PWM.
They don't seem to be of good quality either, 2 were not recognised at all.
 
Changed, but same result.
If I still feel like it later, I will change the motors.

Edit:
Same result, with other Motor
 
Now i know why my PowerPCB won't shut down, the capacitor is the problem.
It discharges too slowly, after 5 minutes I still have just under 10V at the 24V output without power input.
I'll have to order another one, although it's also 50V 100uf.
Very strange...
 
Back
Top