TT Motor Mount - Gridfinity Refined 2x1

This is a relatively simple mount for one of those Yellow TT motors, on a gridfinity refined 2x1 baseplate. 

For anyone looking to use gridfinity to trial and develop electronics, and robotics - this is hopefully a useful addition, as it makes it very simple indeed to take a gridfinity base, and bolt on some motors and wheels, so whatever else you put on there will be carried around with the base. 

I've coupled this with my previous 4x2 gridfinity case for a breadboard and battery, and have created a simple robot which can be very easily added to. The photos show a 4x4 base in action, but I'm sure the motors have the power to drive 5x4 and more. 

Design details: 

I've created RHS and LHS versions of this - so you can mix and match as you need (you'll typically want 2 of each for a 4-wheel vehicle). 

I've used @Grizzie17 's great gridfinity refined base for this, as I love it for the push-fit battery holders - but more importantly here, the screw-fit bases, which allow a very solid hold. In this application, the weight of all other grids is held by the 4 motor pods, and 16 pairs of magnets might be enough in some situations, and therefore feel free to just use a magnetic base with this if desired - but I would recommend an original grifinity refined base (as in the photos), with the screw mounts - so that the motor pods can be firmly attached. 

I've got with captive nuts for the fixings for the motor - and I've trialled a very small retaining wall at the bottom of these cavities. This should mean that the nut can be pushed in from the top, and it will stay in place while you secure the M3 bolt (rather than needing glue or fingers in there). It worked great for me - but please do let me know if this doesn't work for you. 

I've used tight tolerances on this model - as I wanted the motor held firmly. This includes a tight 3mm fit on the M3 clearance holes, and a tight fit on the captive nuts. This is deliberate, and worth the extra effort fitting these in once, in return for a solid motor hold in my opinion. I'm not too sure on the tolerance on the TT motors though -so feel free to remix if I've not left enough tolerance for different manufacturers. 

I put a through-hole in the mount for the bottom mounting hole in the motor - but there isn't space for a captive nut, and it's not necessary if you mount at the back and the top. I wanted to maximise the ground-clearance of the robot, so didn't put any extra material under the motor that would have made this second hole usable with a standard M3 nut and both. So use if needed, but be aware of that limitation. 

Note that in the photo I haven't yet wired up 2 of the motors - so don't copy it exactly :) But my 6-year-old did put together 3 of those motors into their mounts and then on to the base plate with the screw-fixing so it's been tested as a good option to help kids get into electronics and robots! 

Kudos again to @Grizzie17 for Gridfinity Refined, @Kytor for the STEP versions of the baseplates (which I've added the screw-fixings back into and obviously Zack Freedman for the gridfinity movement.. 

Sub-component stuff: 

The breadboard holder that is the heart of this simple robot is my (remixed) model here: https://www.printables.com/model/1134570-gridfinity-4x2-breadboard-holder-with-extras

The Gridfinity Refined baseplate, and the screw fixing pieces were from this collection: 

https://www.printables.com/model/413761-gridfinity-refined

The electronics in the photo are part of a kit I bought for the Raspberry Pi Pico - which I would recommend - it comes with the breadboard, pico, power supply, jumper wires, LCD and a whole range of other bits to prototype some nice projects. https://amzn.to/4gSPci6. I did use the 293 motor controller in this kit to drive the 2 sets of motors too. 

The motors and wheels were separate, and are this kit here: https://amzn.to/3DRoaJS 

This robot has a RPi pico on it, so can do some automated stuff - but I've also put a receiver on it, so I can do simple remote control - this is the package I used for that: https://amzn.to/4jcd4z1 

These are the magnets I use for all my gridfinity stuff: https://amzn.to/3DFTKtO.  

(Note: These are associate links, which means that they don't cost you any more, but I get a small cut if you purchase via these links. This isn't a big money-spinner, but I find it so useful to have sub-components linked in models that I download - so I know I'm getting exactly the right bits without much research, and it helps support my tinkering!).