Newbie

[Frozen Goat]

Hi Everyone,

I am as new as they come to the RC world. I recently built a Mowbot, not because I'm COMPLETELY lazy but more out of necessity. I have deep ditches that are unsafe to mow. After a few years of dealing with the municipality (that's a story for another time) I decided to build the Mowbot so I could maintain the grass in the ditches without endangering my safety. After going back to the drawing board a few times I've finally completed the project. I have tested in in my ditches and it works pretty good.

I went to do some final testing today and started to notice some issues with the control of it. Before I get into that, here's the specs.

Radio Tactic TTX410

Power Supply 2 x 12 Volt U1 Deep Cycle batteries

Motors 2 x Jet 3 Ultra 24 Volt power chair motors Not sure of the electrical specs but I'm using all of the factory wiring harnesses including the 50 amp circuit breaker


Motor Controller Sabertooth 2x 25 amp
Input voltage: 6-24V nominal, 30V absolute max.

Output Current: Up to 25A continuous per channel. Peak loads may be up to 50A per channel for a few seconds.

Recommended power sources are: • 5 to 18 cells high capacity NiMH or NiCd • 2s to 6s lithium ion or lithium polymer. Sabertooth motor drivers have a lithium battery mode to prevent cell damage due to over-discharge of lithium battery packs. • 6v to 24v high capacity lead acid • 6v to 24v power supply (when in parallel with a suitable battery).

All batteries must be capable of maintaining a steady voltage when supplying 20+ amps (AA or 9V batteries aren’t going to cut it! An 18Ah lead-acid battery is a good starting point)

Using a 100 amp battery disconnect switch for on/off for the Sabertooth, e brakes and Tactic RX. The Sabertooth supplies the 5V for the RX.

Everything functions normally until I enter quick commands on either of the control sticks. Once I do so it appears the zero point resets and the mowbot will run "out of control" even with the sticks sitting at zero. I can move the sticks to compensate for the adjustment which allows me to regain control but the only real way to correct it is to cycle the power to the RX so the zero points are reset.

Here are 2 videos showing the issue and picture of the mowbot

https://drive.google.com/open?id=13K...7w_abblQN3kyFR

https://drive.google.com/open?id=1kl...mxVQteZ9clyC2J

I've reached out to Tactic to see if they could help me. The radio and motor controller are both brand new as are the batteries.

Figured I'd reach out to people who have experience to see if I could get any suggestions on what the issue is.

Thanks in Advance.

[Skier1960]

Do you have some videos?

[Frozen Goat]

Hi Skier yes there's 2 links in the post.

[itizme]

Maybe look at noise as the issue

Optic isolator between esc and receiver?

[Frozen Goat]

Hi Itizme,

Thank you for the suggestion. I thought it may be noise so I isolated the RX outside of the container that the MC is located in and then shielded the container with metal tape. This obviously wouldn't negate any noise being induced into the 5V control lines though. I have to wonder if my RX isn't failing. I played with it a bit more and now the failsafe feature doesn't work properly either. Any chance that motor noise feeding back into the RX could damage it?

[Heligaz]

How far are you from the mower when you loose connection?

[itizme]

Hi Itizme,

Thank you for the suggestion. I thought it may be noise so I isolated the RX outside of the container that the MC is located in and then shielded the container with metal tape. This obviously wouldn't negate any noise being induced into the 5V control lines though. I have to wonder if my RX isn't failing. I played with it a bit more and now the failsafe feature doesn't work properly either. Any chance that motor noise feeding back into the RX could damage it?

As unlikely as that is anything is possible. Only way to find out is to try.
Something else you may try would be to use a servo programmer to operate as if it were your stick/radio/receiver. Anytime you can put a dividing line into your troubleshooting it narrows down your investigation.

[Skier1960]

Hi Skier yes there's 2 links in the post.

Oh Yeah!!! Doh...

[Frozen Goat]

How far are you from the mower when you loose connection?

Hi Heligaz,

In the videos I'm less than a foot away. I've had it happen at all distances. I've never been more than 30' away from it at this point as I can't trust it.

[Frozen Goat]

As unlikely as that is anything is possible. Only way to find out is to try.
Something else you may try would be to use a servo programmer to operate as if it were your stick/radio/receiver. Anytime you can put a dividing line into your troubleshooting it narrows down your investigation.

Hi Itizme,

Agreed. I'll look into both options. Thanks.