Spent a bit of time today fiddling with timer interrupts so that I can get fine control of the speed of the motors on the HullPixelBot. Because they are steppers they are quite precise, which means I can get the bot to trace accurate curves.
The next thing I have to do is put the light and distance sensor on the front (along with a bumper) and then we'll have a proper robot.
Today I showed some kids at our Control Freaks event some HullPixelbot devices.
They all wanted one. Which was nice. I'm working on ways we can get some of the kits made. If you're in Hull and have some 3D printing time spare (or just want to show off with your printer) give me a yell and we can try to put something together.
I've reached the point in 3D design where the hard part is not expressing the design. It's deciding what the design should be. I regard this as progress. Above you can see the new pixel mounts for the HullPixelBot that we've been playing with at C4DI.
Each bot will have two pixels. One at the top between the wheels to make it easy to do persistence of vision photography. And one at the back for other HullPixelBots to find and follow.
I unveiled the new design to an awestruck audience at the hardware meetup tonight. Unfortunately I also unveiled a rather nasty power issue where the robot motors cut out when the lights were turned on. Oh well. It might be that we need extra volts for the pixels...
Anyhoo, I'll be posting the new designs in a little while, once I'm sure that it all fits together properly.
I gave away a couple of 3D printed kits to new folks who had come along. If you want to come, get some parts and have a go at building your own robot (it won't cost you more than a tenner to build) then sign up for our next meetup on 18th August. All are welcome, young or old, experienced or not. Sign up here.
The idea behind HullPixelBot is that it is a roving pixel robot. From Hull. We've got the robot part working quite nicely now, with motors and wheels and everything. But we've been missing the pixel bit. So today I spent some time crafting the holders for the pixels mounts.
The plan is to have two pixels on a robot.. One on the top, directly between the two wheels. We can use this to "draw with light" and whatnot. The other pixel is mounted on the back of the robot. On the front of the robot we are going to put a light sensor so that a robot can find and follow another robot with a particular coloured pixel on the back.
I'm going to spend the next day or so fiddling with the design and printing test versions to make sure it all fits together. Exciting stuff.
Â
Got together, built a robot, talked technical and made some plans for the future.
Just another hardware meetup at C4DI. The next one is in two weeks, You can sign up here. It's free and anyone can come along. It's going to be a rather special meeting. It's when we put the pixel into HullPixelBot.
I do find some of the product descriptions delightful
Today I made the mistake of going onto the AliExpress web site to look at some prices. I ended up spending over fifty pounds, but the good news is that I've bought enough bits to make five of the new, super, stretch HullPixelBots with pens.
We had a pretty good turnout tonight at the C4DI hardware group. The focus was on building and powering up HullPixelBots. I'd printed a few sets of parts and some folks had even turned up with all the other bits, so we made some robots from scratch. Important lesson learned, make sure that you link the two pins on the motor driver board If you want the motors to work.
I even managed to get the WiFi working on the "bot with two brains". The code made the motor move when I browsed a website on the phone. From an access point hosted on the robot. My dream of a networked army of robots doing my bidding is coming closer.
I think you should know I'm rather proud of this...
I've just finished building the prototype for the dual processor version of the HullPIxelBot. A single Arduino is a nice enough way to do simple robot control. But I want WiFi. And access points. And web servers. So I've coupled an ESP8266 device (in this case the Node MCU) up to an Arduino Pro-Mini. The Pro-Mini takes care of the low level motor control, producing the signals that will drive the steppers. The ESP8266 device doesn't really have enough pins for the motors, and it has better things to do than drive steppers, so I've linked the two with a serial connection.
Since the Pro-Mini costs around a pound and has a negligible effect on power consumption I reckon it is worth doing. At the moment we have a really simple one byte command protocol, but I can build that up a bit if I need to use the Pro-Mini to do some sensor integration.
Next step is to work up the web side so that I can make a wireless, web controlled robot. Then we add the coloured pixels to the bot and we are really in business.
I'll be releasing all the code and the circuit diagrams later. If you want to see the real thing, come along to C4DI tomorrow evening at 6:00 pm.
We will be holding a special Robt Building meetup this Thursday (16th of June) at C4DI. I'll be bringing along a bunch of printed components (see above) for people to use to build their own robots. If you've been collecting the hardware to build your own robot, come along and we'll help you put it together and get it moving.
I'll also be showing off the latest "two brained" version of the PixelBot and we'll be discussing the way forward. Everything will start around 6:00 at C4DI in Hull on Thursday.
We had another of our hardware hacking group meetings last night. Plenty of great discussion, a lot of it focused on the HullPixelBot. Robin had assembled one and added some sensors that allowed it to chase light. Which mostly worked. We're planning a "bot assembly" evening on the 16th of June. I'm going to print out a bunch of chassis and anyone who fancies a bot of their own can come along and build it with us. Then we'll try to get them all going. You can find the build instructions on the Hull PixelBot microsite here. They include how to get all the part's you'll need. It shouldn't cost you more than ten pounds or so.
We also have a Google group about matters Hull PixelBot. If you want the details ping me a message (or add a comment) and I'll get you registered.
I've been spending the odd five minutes here and there designing and printing parts for a little robot that I want everybody to build. I've called it the HullPixelBot, because I want to turn it into a mobile pixel. I had lots of fun making my wedding lights a couple of years ago and so I thought I'd have a go at making a mobile version. The idea is that if I can get enough of them together and network them we could have a whole bunch of mobile coloured dots which we can display patterns on.
It's kind of artistic. But in a technical way.
Sooooo, I want to get everybody making little Arduino powered robots. The target price for parts for the robot is less than ten pounds. I'm using very cheap stepper motors which work fine. They are a bit slow, but they provide a precision of movement which you just can't get with standard DC motors. I'm also using catapult ammunition (really) for the caster and four AA batteries provide the power. There are holes you can use to attach sensors and we will develop the design as we go along.
I'm taking a bunch of parts to the C4DI Hardware Meetup on Thursday this week. If you fancy having a go at building a pixel bot, come along to find out more.
I've been spending what spare time I have (not much) playing with Python in FreeCad. These are the results I'm getting at the moment. Quite pleasing.
Rob Miles is technology author and educator who spent many years as a lecturer in Computer Science at the University of Hull. He is also a Microsoft Developer Technologies MVP. He is into technology, teaching and photography. He is the author of the World Famous C# Yellow Book and almost as handsome as he thinks he is.
