Comment on Considering positioning strategies for autonomous mechanum-wheeled robots
rufus@discuss.tchncs.de 1 year ago
I think mecanum wheels slip quite a bit. So I’m not sure how effective those encoders are. But I’ve only ever tried 3d-printed ones. So I’m not super sure.
You’re sure your STEM students are ready to handle the LiDAR? Manage point clouds, do the arithmetic, path planning etc? We had a practical course with little robots. But they had 3 of those sharp distance sensors at the front and a bumper with a switch. This was enough to teach many concepts and also enough to implement for the students for something that was just a project and not a full time job.
And our robots hat the motor drivers (h-bridges) replaceable on socket terminals because every so often someone wasn’t very clever or didn’t listen in the lectures.
Saigonauticon@voltage.vn 1 year ago
They’re university software engineering students, probably a year or two into their degrees. I’m hoping to provide the robots as completed units that are controlled via API, because we’re not likely to get many students with electrical, mechanical, or embedded backgrounds. You’re right about the complexity though, and that’s something I’ve been thinking about – I guess I’ll start out with a bit of optimism regarding their talents, and scale back if needed :D
I don’t really have a scope, budget, timeline, or audience properly defined for this project – in short my client has a STEM program for building and interacting with digital maps, but it’s way too boring and I’m determined to breathe some life into it. So I’m going to have to play a lot of things by ear.
rufus@discuss.tchncs.de 1 year ago
Well, kids / young people / students will surprise you anyways. No matter what you planned ahead. I think teaching this way just requires you to stay flexible and try things with the students and see what works. University students will benefit from a little challenge, but it shouldn’t be impossible and get them frustrated. I’ve never taught myself, but I bet it’s difficult to hit that balance.
Programming little robots is awesome, though. I think it’s on a whole other level to see robots move and do tasks, than to look at your screen and program something that changes a few pixels there. My university course was more related to embedded devices and closer to the electronics. It teaches you valuable lessons when forced to interact with some electronics, real-world physics, constrained resources and you need to get your maths right. Usually students are concerned with something like Java, learning object-oriented programming or handling some big frameworks. Or learning maths. And robotics teaches you to really pay attention, combine different skill-sets and do things without an easy route available.
Maybe it’s just me who likes electronics too much. But I’m sure the kind of motivation you get by watching a real robot move and it runs your code, is unique. And kind of universal. You can do this in pre-school or in university to spark their imagination and motivation.
Your task is a bit different. If you’re teaching something like simultaneous localization and mapping and the students also have to deal with all the robotics, sensors and real-word problems, this might be more of an ordeal for them than fun. Even dealing with noisy sensor values is a hassle until you get to grasp the bigger picture.
If you’re giving them access to an API, you can choose and adjust what kind of abstraction you’re providing them. Give them something high-level or have them do more work. You could prepare something and adjust the level of detail while teaching. Maybe skip something and give them working code via your API so they can focus on the problem they’re actually supposed to learn. You can also do it the other way round. Let them start with all low level stuff handled for them and learn the concepts. Then let them dig down and see what your API functions have abstracted away until then.
I’m sure including actual robotics is going to get them more motivated in contrast to running a simulation.
Saigonauticon@voltage.vn 1 year ago
Haha, I know exactly what you mean – I’m most interested in resource-constrained embedded systems. I like the attiny10 a lot. At work I mostly write Python, but in my own time it’s mostly assembly language. It feels more concrete, every decision matters, and anything that goes wrong is 100% your fault as there are relatively few bugs at that level. It’s a lot of fun. Also the datasheet is very good.
I’m self-taught with all the electronics stuff, I paid for it by teaching a course on whatever thing I did most recently. Then I’d use the proceeds to buy tools and parts for the next big (often dumb) idea. I’d also ask for the software engineering assignments from colleagues in those programs, and complete them in my spare time. It was puzzling to a few people why I would want to do assignments, and indeed some were very boring (oh god Java + Spring framework) but others were quite interesting (formal study of algorithms). Sadly, economic reality kicked in and I had to run a company instead of pursuing my education further (I still try to do one ridiculous engineering thing per year though).
I guess there’s a real risk (…like 100%) that I overestimate the motivation students have – so I think I’m going to take your advice and set the level of abstraction with something API-like to abstract away the low-level components (this is closer to my client’s domain). I’m imagining a robot that acts as a WiFi access point, and having something “like an API” that works over UDP packets that describe high-level functions. Then start with something simple – like a digital map with known starting location, and a small obstacle course that can be completed with simple distance measurement, no point clouds. If that goes well, I can develop towards more complex material – probably not full SLAM, but maybe localization on a pre-mapped surface. I have plenty of my own code as examples of how to do simple UDP communications in Python, I could expand it into a custom library.
Sort of like Logo from 1983, but with a physical robot and sensors. I’m a little to young to have used Logo, but the computer lab in my school was really outdated so I got to try it once :D
rufus@discuss.tchncs.de 1 year ago
Well, there’s also turtles to program in Python (i think) and there is Scratch.
Definitely sounds like it. But a motivated teacher is a very good thing. Maybe you’re able to get that spark across to some of the students.
You can always have some extra assignments ready, just in case someone is curious and wants to do/know more. A room full of studens will have a mixed amount of knowledge, abilities and motivation anyways.
I also ate a few books and datasheets on the Atmel chips in my lifetime. Their design is well-thought-out and probably an excellent subject to learn the concepts about microcontrollers.
As of now I like the ESP32. It is ridiculously overpowered if you’re used to something like the ATtinies or old ATmegas. With (at least) 520kB of RAM, two cores that work at 240MHz (depending on variant) and very nice peripherals. Also WiFi connectivity is really useful. But it definitely adds to the fun if you programmed the more constrained (previous generation of) microcontrollers and know how spoiled you are and can feel like a supervillain wasting hundreds of kilobytes of memory deliberately. Or (ab)use some of the peripherals for things that wouldn’t be possible with the few timers available on the Atmel chips. Or do trigonometry at crazy frequencies for your robots, because you can handle 32bit floating point numbers. But I’d agree, that doesn’t teach you the same things if you can do floating point arithmetics for cheap and don’t know if calculating a square root is an easy or difficult thing to do. The STM chips also have nice peripherals. But I haven’t really fiddled around with those.
Definitely hope you’ll have fun being involved in that STEM program.