So… didn’t manage to get a post up last week, because it was a mad week, but have a moment’s breathing space right now to reflect upon what has happened in that time.
First up, the chassis design continues evolving… actually even this photo is a little out-of-date, but the main idea being that we now have rhomboid tracks. The footprint is marginally larger (still well within the A4 paper), but it gets over things more easily, and I think it might actually go faster too. Not that it needs to go faster. In fact it goes so fast at the moment that control is the issue!
In my last blog post, I was talking about options to communicate between the pi zero driving the motors (and handling remote control) and the pi 3 with the sensors and handling autonomous control. I realised afterwards that the option we used for the lights pi zero last year – USB – isn’t available, because the remote control wifi dongle uses the pi zero’s USB port. But in any case, I hadn’t really want to use that option anyway. So I was considering I2C and SPI… but it was pointed out to me, when I was chatting to people about it at Manchester Raspberry Jam, that UART was probably the easiest option. And I have to agree – why I didn’t consider this myself, I don’t know! So that’s one problem solved… or at least a decision made – I still need to test it.
Also on the agenda has been testing my sensors. And that’s sort of been successful. Since the last competition, I’ve been keeping my eye out for any sensor that might be useful, ordering them, and tucking them away till I had time to test them out. The problem is, now that I have time (sort of) to test them out, I’m not quite sure where I’ve tucked them all away! 🙃😊 But so far, it’s clear that we’ll be using VL53L0X sensors again this year – they worked a charm last year, and there’s no reason not to use them again. Obviously we’ll need to use a camera for the Over the Rainbow challenge, and no need for the myriad of line following sensors left over from last year. (While we could do line following on the straight line speed test, I would prefer to use the distance sensors. Yes the chicanes make it a bit more tricky this year, but I plan to handle that by having distance sensors on both sides of the robot and keeping equidistant from the walls.) I’m still playing with the idea of using a gyroscope/magnometer for the maze as well…
It’s all about learning though!
OK, so that’s all positive, but I think it’s obvious from the title that it hasn’t all been that way. That’s a good thing, not a bad thing though, because every setback is a wonderful learning experience for my kids.
Angus (10 years old) was already heavily involved last year, building the chassis and contributing to the coding. This year, he’s again in charge of chassis design, and it’s obvious he’s putting much more thought into the engineering of it. At the moment we haven’t done much software development, but he’s been writing software for other things, and reading Computational Fairy Tales and Best Practices of Spell Design by Jeremy Kubica. These books are wonderful ways to introduce young adults (he reads well above his age) to computational thinking, without writing any code. So I’m expecting him to make significant contributions to the code this year.
Erin (7 years old) was less involved last year – an interested observer more than anything. But over the summer, she told me “Mum, I want to learn to code!” – and I’m sure that’s come about because of pi wars. So we’ve started looking at coding using the Kano operating system for Raspberry Pi – it has a bunch of great tutorials for children included. She was working on its turtle-graphics-like drawing package when she came to Manchester Raspberry Jam with me, and very happy to create Stick Man, amongst other things, while she was at it. It’s still not clear exactly what her contribution will be to Glitterator 2, but her peripheral involvement so far has opened her up to new challenges, and that alone is fantastic as far as I’m concerned.
So… I still haven’t got to our setback. Well, some background first. We parked ourselves next to Nick Young at Manchester Raspberry Jam on Saturday – just Erin and I, as Angus was competing in a cross country competition. Nick had a multi-segmented robot called “Pithon” in last year’s pi wars competition. He was disappointed that he didn’t spend enough time on it, so it didn’t perform very well, but he’s continuing to work on it – and I must say it is now much more impressive! But shortly after we arrived, it started smoking. Somehow one of the battery packs had shorted. No major drama, but a nasty smell.
Well, on Sunday morning, I was doing something upstairs, and Angus was test driving Glitterator 2 downstairs. I hadn’t registered that it had stopped driving around, but then heard Erin yelling, “Mum, I feel sick! Angus is making smoke like at the Pi Jam yesterday.” Ooops. And unlike Nick, who was just using AA battery packs, we have LiPos. Fortunately I’d been through the risks of battery explosions with both kids, and Angus had immediately moved the whole robot outside. I cautiously peeked out the door, and it had stopped smoking. Definitely still hot though. Retrieved the LiPos and put them in the battery bag, leaving that outside, then brought the robot in for post-mortem. Seems that the screws on the power terminals had come a bit loose – possibly due to rough driving – exposing some wire, and these wires had crossed. Luckily, there seems to be minimal damage to the electronics. But you know what? The house really stinks! And the terminals melted…
And a bit of fun…
Only a little bit Pi Wars related, but also this week I had a day off work in order to visit the place that will be my new workplace in January – the Department of Computer Science at the University of Sheffield. We talked about my role there, what I would be teaching, and various other things. One of those things is that I’m keen to establish a Raspberry Jam in Sheffield – and it looks like it will go ahead. I’m not sure how long it will take to get it off the ground, but for anyone who is interested, please get in touch.
While I was in Sheffield, I also took the opportunity to visit Pimoroni.
I should point out that they are not set up to receive visitors – I organised this well in advance.
I talked Pi Wars with Tanya, who’s recently been given a place, along with her son, in the beginners competition, after being on the reserve list, and also got a tour of the factory (spending a good 5 minutes or more being mesmerised by the pick and place machine) and chatting with Sandy and Phil as well. I came away with a wonderful swag of goodies, but could have spent a fortune more… so much STUFF!
Cutest of all was the new product “Bearable” (yes, I know it’s a fox, but there’s a bear version of it too), which Erin took great delight in showing off to everyone at the Raspberry Jam. The crocodile clips connect to a sensor that make the LEDs flash. There are two types of sensor – light or motion – and she spent a lot of time jumping around to show off the motion sensor.