R/C lawnmower/ sabertooth 2x32 - Kill switch using transmitter switch

I’m building a robotic lawnmower for the steep hill behind my house using a 6.5HP Craftsman gas mower from Craigslist, Jazzy wheelchair motors from eBay, a Sabertooth 2x32 motor controller, and Flysky r/c transmitter/receiver. The first stage of this project is simply remote control, and has recently been completed.

I’m currently bench testing (wheels off the ground) the r/c functions and before taking it off the gurney and running it around the driveway, I’d like to have more kill switch reduncancy. Currently, I’m using only the Flysky Tx/Rx Failsafe configuration which stops the motors and applies the motor brakes when signal is lost, but I would like some guidance on dedicating a Tx/Rx channel and transmitter switch as a live kill switch. Has anyone done this?

My transmitter is a Flysky FSS-i6X and the receiver is a FS-IA6.


Hello @BGood and welcome to the RobotShop community,

You could use an RC relay connected to the main battery on the same or a separate RC remote.

You simply need to verify that the switch is capable of withstanding the current required by the motors. In case 10A is enough here are some options:

However, if you need a higher current rating you can find some other options in the Relay & LED Controllers section of the store.

Good luck with your project!

Thanks for the ideas geraldinebc15. I went ahead and road tested the robo-mower’s locomotion on the neighborhood streets and gas engine in my driveway. The failsafe circuits I currently have are wheelchair motor shutdown on loss of r/c signal, gas motor shutoff and safety brake on release of safety cable, and magneto primary grounding via SPST toggle.

I bought a couple of 2-channel r/c relays and buck converter for development of additional remote safety circuits but have not implemented these yet.

I am also looking for either: 1) a wireless camera and remote receiver monitor; and/or 2) an accurate routing/positioning technology so I don’t have to follow the mower around all over the yard.

If anyone has suggestions, please post a comment.

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@BGood When it comes to wireless video, take a look at what the drone market has to offer (some great wireless cameras, receivers, monitors, long range gear etc.)

@BGood I’m using a Tyco/Kilovac EV200AAANA.It is a little bigger physically and slightly more expensive than most “automotive type” but its capability is well worth it, imho. My controls are still on the bench as I am waiting on mechanical parts from the machine shop to complete my mower.
If you pull up the spec sheet, i think you’ll be impressed. Pretty sure i picked it up for around 50-60 bucks on EBAY.