iMow project

JohnGay · 2012-04-30 09:30

I am now the proud owner of a very well used, and slightly broken Toro iMow. Haven't had a chance to open it up yet, but the guy I got it off thinks one of the gearboxes might be chewed up.
Otherwise, I should have 2X12V drive motors, the blade motor, 2X6V batteries and various other parts to play with. The price was right for "I just want to get it out of my garage." (-=
As soon as I get it home I'll have a look at what seems to be broken. With any luck, maybe I can use the motors and wheels with different gears or belt drive?

I'll have a better idea of what I can do once I get it home and apart. Then the fun begins (-=

erco · 2012-04-30 10:00

Will R2-D2 be piloting it? Or maybe that job belongs to CP3-Mow...

JohnGay · 2012-04-30 12:26

Actually, the voice-activated R2-D2 project is something I've wanted to do since I first saw one in Barnes&Noble. Unfortunately, my budget and skill level is more suited to buying a Magician Chassis and trying to make it drive straight. However, I was telling a co-worker about the Magician Chassis I planned to get when he said. "That looks a lot like a robot I've got. I'll give it to you if you want. By the way, to cuts grass."

I figured the iMow was the same as the Magician Chassis but a more useful size. And the price was right. If I can get the motors working someway, I just need the right size motor drivers to plug in my QuickStart board and start playing around.

Especially since my finacial advisor hasn't picked up the hint that I want the Magician Chassis yet. Maybe when this iMow starts chasing her dogs around the house she'll get me one (-=

JohnGay · 2012-05-08 18:18

Just discovered the magic trick to get into this iMow. Looks like I've got 5 X 24V motors, several gears, but 1 is a bit chewed up, and 2 dead 12V batteries.
The motors are Johnson and have 97750 on them, but I can't find any info on them. They measure 2 ohms. If I knew the current, I could get/make some drivers for the motors. Or I could try interfacing the built-in drivers from the board.
Not sure I could find a replacement gear for the existing drive train, but it gives me something else I can play with along with my mousebot.

Matt Gilliland · 2012-05-08 20:17

Will R2-D2 be piloting it? Or maybe that job belongs to CP3-Mow...

Well done Padawood!
-MattG

Matt Gilliland · 2012-05-08 20:21

Hey JohnGay -
How about some pics?

-MattG

JohnGay · 2012-05-12 10:18

Pics coming shortly. I just discovered the iMow also has a fluxgate! Guess I'll be building a time-travelling robot! Or was that a flux capacitor?

JohnGay · 2012-05-12 12:04

Here's the iMow:

And this is it with the top off:

You can see the two drive motors at the rear between the wheels. There are also three blade motors, one I've removed. They all seem to be the same type but there's no markings except this sticker:

I've tried googling, but only found other people looking for info about the 97750 motor from Johnson. The mower runs on two 12V batteries so I presume these are 24V motors. The Starboard drive train is damaged like so:

You can see the damaged teeth on the first gear and the motor is tilted from the plastic melting when it over heated. not sure if i'm going to try fixing the gear or just remove it and drive the next gear directly. I'm still thinking about what I'm going to do with the other three motors.

I've also got a fluxgate as well! I might try using that with my mousebot.

JohnGay · 2012-05-22 07:01

Well, I still can't find any info for these motors. I hooked one upto an adjustable power supply and ran it at 28 Volts, my assistant was stuck in aircraft mode. In idle it only sucks a few 100mA's or so. Adding a load we got it upto about 6A, and melted the end off the gear (-=

I found this http://www.ikalogic.com/build-a-5a-h-bridge-motor-driver-new-version/ which seems like a good H-Bridge design but I did have a few changes I wanted to add.

Since the propeller runs at CMOS and not TTL, I wanted to swap the TTL chips with their CMOS equivulents and change the regulator for a 3.6V one. It says it can handle 12V or 24V, but it has a 5A limit. Since I can't find reliable current ratings for my motors, I was wondering if I could add a current limiting circuit to keep the motor from pulling more than 5A. I'm also considering running these at 12V instead if it's easier to get a single 12V battery but I'm not sure just how that will affect the current and power of this motor.

Any feedback would be greatly appreciated.

Cheers,

John Gay

JohnGay · 2012-05-30 15:30

Since I can't find any info from my motor, I checked the driver board from the iMow. The drive motors seem to have a full H-bridge made from IRLW44A. These are power mosfets rated at 60 V and 50 A! The cutter motors have one IRLW44A and one SFW9W34. This one is only 18 A. These both use the same motor, but the cutters only run one direction and only have the grass for resistance. So I'm guessing a 5 A H-bridge won't be enough?
Any assistance if figuring out this motors rating would be greatly appreciated.

iMow project

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