Hi DGB,

Thanks for stopping by. Completely agree that it is quite overwhelming for a while when you jump into this field. Hope to release some software at some point not too far out to help with this 🙂

Take care,

Roby

Hi Crhistian — The Pixhawk Signal 1 and Signal 3 wires are directly connected to 1 and 2 on the Sabertooth — that’s where Pixhawk is sending PWM values out to the Sabertooth. You’re right that I should probably do a post on configuring with Mission Planner – the amount of options and parameters is pretty vast and can be overwhelming.

Thanks Jorrit — Guess I’ve missed your question!

many thanks

Jorrit

Good thinking Roby, many a time have I had to stoop down to wheel my robot back to the garage. It’s quite the hassle.

I feel foolish for not thinking about moving the compass itself further away from the motors, that would be an elegant solution 😉 Right now I’ve got 10 pounds of poo in a 2 pound enclosure, I like how spread out everything is on your setup.

True story about enclosures and platform real estate, I’ve drawn most of my stuff up in a CAD system and I go through three or four iterations of increasing enclosure sizes before I am finished with a design.

Hi Bob,

There are several advantages (for my experiments) to the tall multi-level platform:

1. Ability to put compass away from motors / motor controllers / ferrous base. Notice that the compass is on the top. Also note the ad-hoc insulation around the compass — the HMC5883 is sensitive to sudden temperature changes. For your situation, why not put your flight controller near CG (likely better for the accells/gyros) and just rely on an external compass that’s mounted a bit away from the motors and motor controllers. These compasses are super-light if you buy them a la carte.
2. More room to mount all electronics & antennas as far away from each-other as possible. My observation is that once you start building one of these robots, you rarely look around and say “Man, I’ve got too much room on this platform and no new components to install.”
3. Ease of pushing the robot back to the shop when it breaks down — I’m no longer 16 and thus don’t like bending over to push a big heavy robot back home.

Note that the big platform is made out of non-ferrous aluminum. This yields two advantages: 1. Super-light (~7kg) and 2. Easy to drill & cut (nothing like burning through drill bits on hard metal to dampen an otherwise wonderfully satisfying afternoon in the shop).

So, since the base is 70kg, the weight of the platform doesn’t hurt the CG significantly (for my experimental use cases).

Glad you stopped by & best wishes with your own missions!

Cheers,

Roby

Nice setup you have there. Looks fantastic! Is there a reason (or rather, what was the reason) that you built the frame for your electronics so tall? It seems to me that you’d want your center of gravity for the robot to be lower, but with two SLA batteries on the bottom I’m sure it’s not an issue.

I am working on a similar setup but without some of the bells and whistles your setup has. Did you have any issues with compass interference from your motors? My compass and Pixhawk were ~12in from the motors and I noticed my compass readings were all over the place and my autonomous missions would never drive in a straight line. I really want to avoid placing the flight controller and compass too far above the vehicle CG but I may not have a choice. Just looking for your two cents, if you have some.

Hope you get back to posting soon, this place is a treasure trove of information!

Thanks,

Bob