We’re getting to the point that seeing 3D printed parts in a project or hack isn’t as exciting as it was just a few years ago. The proliferation of low-cost desktop 3D printers means that finding a printer to squirt out a few parts for your build isn’t the adventure it once was. Gone are the days of heading to a local hackerspace or college hoping their janky Mendel felt like working that day. But all that really means is that hackers and makers now have the ability to utilize 3D printing even more. Forget printing one or two parts of your design, just print the whole thing.
That’s exactly what [Nik Ivanov] did with Watney, his fully 3D printed rover project. After lamenting that many so-called 3D printed rovers were anything but, he set out to design one that was not only made primarily of printed parts, but was robust enough to put some real work in. Over the course of several design iterations, he built a very capable all-wheel drive platform that needs only some electronics and a handful of M3 screws to leap into action.
As long as you’ve got a 3D printer big enough to handle the roughly 120mm x 190mm dimensions of this bot’s body, you’re well on the way to owning your very own video rover. [Nik] recommends printing everything in PETG, no doubt for its increased strength when it comes to things like the drive gears. Plus it’s low warp, which is really going to help when printing the top and bottom sections of the body. TPU is advised for the tires, but if you don’t have any (or your printer chokes on flexible filaments) you can just wrap the wheels with wide rubber bands.
[Nik] is using a Raspberry Pi Zero W as the brains of the operation, but the beauty of an open platform like this is that you could easily swap out the controls for something else to meet your needs. In addition to the Pi, there’s a L298N H-bridge motor controller to interface with the dual geared motors, as well as a servo to provide tilt for the SainSmart camera module.
We’ve often been surprised at just how expensive commercial robotics platforms can be, so we’re keenly interested in seeing if the availability of designs like this spur on DIY rover development. Though if you’re looking for something a little more rough and tumble, we’ve seen a 3D printed rover that looks combat-ready.
https://www.youtube.com/watch?v=XmD5N5W7DZs
Here’s mine! (STL files on thingiverse, just look for Android Antbot). Admittedly, it uses lego treads.
The cat’s like… “well, that’s, interesting… I’ll just go groom myself now”
Add a laser pointer though and you might get a reaction. :-)
Yeah, the design has room for two servos (six if you don’t mind a bit of stuttering). I’m worried about accidentally hitting the cat with the laser directly though since it’d be about at eye level.
Yes, that could be catastrophic for feline retinas. Maybe a bright-ish LED focussed into a beam.
Do cats have the most sensitivity to green light just like humans do? Might be possible to use a green laser and use PWM to reduce its power.
Fully 3D printed? What printer and filament did they use to 3D print the BCM2835?
It is sad that I only write to complain about things but I want to point out that this topology of vehicle, with four wheels with parallel axes that can’t change direction is only good for slippery surfaces because the robot essentially can’t move unless the tires lose grip. If you want to have proper motion controlled by two equal motors, you should better use a couple of caster wheels in the back.
Hey Jimmy! No worries about the complaint – it’s a valid one. You’re right – the wheels have to slip for a 0 degree turn. It doesn’t work great on carpets, since there’s too much friction for these little motors to overcome. I sort of worked around it by moving one side forward and the other forward and back rapidly. This causes the rover to turn more like a normal car.
I used casters in the first 3 generations, but decided to go AWD for this one. I didn’t like the look of casters and had concerns regarding durability. Additionally, connecting the wheels directly to motors put a lot of shear strain on the motor shaft. I couldn’t get those rovers to move in a straight line.
The general idea, however, is that if the rover is light enough and the motors are strong enough, making the tires lose grip shouldn’t be an issue – it’s how tanks work, after all. I’m waiting for some N20 motors to arrive – I might be able to get more torque out of them, so Watney could turn in place even on carpet. It should be a drop-in replacement – just a new motor holder and drive gears.
Thanks for taking the time to reply, I appreciate that.
Regarding the issue with the load on the motor axles, I have the same concern in a project I’ve been planning to work on for ages which has to hold a weight of about 20 kg. I was looking for the best solution to couple the shaft of the wheels to the motor in a way that only transferred torque in the direction of spin of the motor but I haven’t found an easy solution that I liked (it should be compact, potentially 3d-printed or perhaps easily and cheaply sourced from Ebay).