A local team of robot builders from Ipswich Makerspace took second place in the Cambridge PiWars competition at the weekend. They entered the Professional category in the prestigious robotics event, a challenge-based robotics competition in which robots created by teams compete in various non-destructive challenges. The Makerspace’s team competed on Sunday and got off to a rocky start getting knocked out of the Pi-Noon robot duel in the first round despite some skilful moves by the driver Jon Leach. They also had issues with the bright sunlight on the course for the Maze and Speed challenges. In training the robot had operated flawlessly under artificial light but the sun interfered with the sensors on the day. The team quickly recovered with an excellent run on the autonomous Line Following and a blistering time for the Crazy Golf with Phil Willis in control. A solid performance on the grinding Obstacle course boosted the team’s morale no end. The final challenge was to present the robot to be judged by Dr Lucy Rogers one of the judges from recent series of Robot Wars. Under Dr Rogers’ critical eye the team explained the highlights of their design helped by Phil’s 10-year old daughter Amy.
The team captain Keith Ellis said “It’s amazing what we were able to achieve with modern technology. Parts were laser cut and 3D-printed, we had custom circuit boards made and we even made use of Open Source computer vision software; 10-years ago we couldn’t have built this robot”.
Steve Chalkley from Ipswich Makerspace said “This was our third PiWars and we’ve been in the top three in each one. We’re very proud of our team and grateful to Rapid Electronics in Colchester for their sponsorship. It allows us to be more adventurous with our designs and produce winning robots”.
About the image:
Left to right: Keith Ellis, Dr Lucy Rogers (Robot Wars), Phil Willis (Amy’s Dad), Jon Leach. Front Amy Willis and Harrison Ellis (holding the trophy backwards, bless).
Dr Lucy Rogers is a chartered engineer, who appeared as a judge in the two most recent series of Robot Wars. She is a Chartered Engineer, Fellow of the Institution of Mechanical Engineers, the Royal Astronomical Society, and the British Interplanetary Society. Her current projects focus on reducing the damage from space debris. At the PiWars weekend Dr Rogers judged the technical and innovation elements of each team’s robot.
Pi Wars is a challenge-based robotics competition in which Raspberry Pi-controlled robots are created by teams and then compete in various non-destructive challenges to earn points. There are prizes awarded at the end of the event. At the weekend teams from schools, families and groups of hobbyists competed for two full days of robotic fun and games. Pi Wars took place in Cambridge, UK and was open to anyone from around the world. This year there was even a team from the USA. It is run by the same team that organises the Cambridge Raspberry Jam.
The Makerspace is a collaborative workshop and community space for creative people to work, gain new skills and inspire each other. After three years of hard work the group now has its own premises in Dove Street which they are filling with high and low tech tools for budding makers. They organise a range of activities such as the regular Thursday project night. The team from the Makerspace has entered all three of the PiWars competitions winning one and coming second in the other two, a fantastic achievement given the level of the opposition. (Website: www.IpswichMakerspace.com)
The Raspberry Pi Foundation was launched in 2008, in order to endorse and develop the Pi. On February 2012, the Raspberry Pi 1 Model B launched at just £25, and offered a 700MHz processor, 512MB of RAM, two USB ports and a GPU capable of 1080p display – all in the palm of your hand. Recent Raspberry Pi sales figures show that the humble board is, in fact, the world’s third best-selling general purpose computer after the Mac and PC. Raspberry Pi achieved this milestone by selling north of 12.5 million boards in five years. This figure beats the previous third place holder, the Commodore 64. What seems like a simple creation went through an arduous journey on its way to becoming the best-selling UK-developed computer in history. (Source: www.raspberrypi.org)
So for the second year we intend to run the robot as a Wifi access point to allow us to connect via ssh and check/debug Tractor Bot. Phil was a bit concerned that the Pi 3’s radio could not run as an access point however he came across this handy guide and we can now connect either to the Pi as an access point or allow it to connect to any of the Wifi networks it knows about.
It works really well and means that Tractor Bot can be run headless very easily.
Pi supporting two wireless interfaces, one using the internal radio as an access point and one using an external dongle bound to Phil’s router. Not to mention a hard line to the same network.
So we now have all the challenges bar the golf sorted, which Keith is working hard on.
Jon is taking care of the leads required for the final design and Phil is going to be cutting the perspex for the body.
We need a bigger laser and more hours in the day…
Early on in the proceedings Jon had suggested we build a maze full size for testing (along with twin robots). So armed with wood, glue and screws he built a maze and even made it in bits so that it fit in his car! At least one pair of jeans paid the price due to the very foamy Gorilla glue. Anyway his hard work paid off…..
This is completely autonomous using three ToF sensors.
The small OLED display was working well for each challenge, allowing the operator to select the challenge by way of a small graphic menu. This is it in extreme close-up.
Jon designed a bitmap editor to create the mini icons and then we painstakingly joined the dots. You can find the editor here: https://leachj.github.io/OLED_Pixel_editor/
So with a couple of challenges down and a reasonable remote control we were feeling fairly happy then we realised that we had less than a month to go! The Pi Party had taken out some of our development time so we had to press on. Keith got on with designing a catapult for the skittles challenge.
Rapid prototyping meant that one email to Phil containing the DXF’s for the laser cutter and the design was being put together for review that evening.
But we still had the golf challenge to put together something for…..
While there has been lots of cutting and 3D printing to do, Phil had also agreed to code the line follower challenge. With TractorBot I we had experimented with the Open CV computer vision software but the results were disappointing. However, with Pi 3 power we thought we might be able to get a Pi Camera to perform the line following duties at reasonable frame rates. Initial trials were encouraging and Keith designed a servo controlled camera case for the front of TractorBot.
The idea being that when the line follower choice was made from the menu, the servo would activate and the line would be illuminated by a Blinkt in the nose. After a few attempts and a lot of tuning we were happy with the result. https://youtu.be/Yrbg0VhtKmk
This is a graphic (sorry) illustration of how far the Pi has developed in just a few years.
We left our robot looking like a moving nest of wires, so what to do about it. Keith’s beautiful 3d renders always miss out the wiring that is a necessary evil when putting one of these together. Thankfully Keith was also able to come up with a solution! Our own interface PCB to get rid of a fair number of wires and sort out the build. Ki-CAD to the rescue. Keith produced some boards to support the Blinkts we were using as well as a main board to fit HAT style on the Pi.
After fitting the various header pins and ribbon cables it really does look the part, much neater.
The third member of the team, Jon, had taken the lead on the software design. He started with our original TractorBot 2015 software and restructured it, to allow better collaboration via GitHub. Jon has created several useful libraries for the Pi and if you are interested you should check out his github page. https://github.com/leachj
Jon already had some good ideas for how to give the robot senses to allow it to navigate the maze, and so purchased some Time of Flight sensors. We used these magical I2C devices in 2015 to keep our speeding robot from crashing into the walls when it came to the straight line challenge. Don’t just take our word for it…
The VL6180X Time of Flight Distance Ranging Sensor is a Time of Flight distance sensor like no other you’ve used! The sensor contains a very tiny laser source, and a matching sensor. The VL6180X can detect the “time of flight”, or how long the laser light has taken to bounce back to the sensor. Since it uses a very narrow light source, it is good for determining the distance of only the surface directly in front of it. Unlike sonars that bounce ultrasonic waves, the ‘cone’ of sensing is very narrow. Unlike IR distance sensors that try to measure the amount of light bounced, the VL6180X is much more precise and doesn’t have linearity problems or ‘double imaging’ where you can’t tell if an object is very far or very close.
Jon set to work improving his VL6180 sensor library and bread boarded 3 sensors using an I2C multiplexer unit from Adafruit to complete the test rig. While his credit card was in his hand he also purchased a small OLED display so we could select the current challenge mode. It’s a really cute display and very clear, just wait until you see it in real life. The menu system even has tiny icons!
While Keith’s beautiful renders look fantastic, the reality is that once you start hooking up the wiring what was a sleek machine begins to look more like a rats nest.
What to do about all those wires…
Well we have a design beautifully modeled in Fusion 360 by Keith our designer extraordinaire.
Time to make it real……
No you’re not seeing double, our secret weapon is two robots! Since both Phil and Jon will be working on different challenges, it was decided to create two robots so the software could be developed in parallel.
We now had our chassis and motors, time to add a Pi and motor controller and let the magic happen.
At least we had something that moved!