Yes that’s right, we won!!!! Well let me clarify that a little. We won the Artistic Merit prize which basically means our robot was the cutest and obviously we are feeling very proud. We can now make the video entries public so take a moment to watch as Stevie Wong introduces you to the sweetest bee robot you’ll ever see with original soundtrack from CyanShaman.

We also did well in the Obstacle Course, coming fifth in our category. This was the most fun to film with lots of drama and near misses. I think we would have come higher if it wasn’t for the really tough competition. Turns out everyone was trying really hard and are also really talented, darn it.

We got fourth place in Up the Garden Path with some excellent programming from Mitch. We love the way his antennae bob back and forth as he shuffles round.

We came a well-earned seventh in the Tidy Up the Toys.

A plucky eighth in Feed the Fish where we got a grand total of one projectile in the fish bowl out of a potential fifteen. But see how beautifully we decorated our bowl.

And finally, we got third place for this blog! Thank you, thank you, you’ve been a wonderful audience, I couldn’t have done it without you. Overall, we came fifth out of ten in our category which we are very pleased with.

Pi Wars 2021 has been absolutely amazing for us this year. It gave us a real focus to keep our PI Jam going in some capacity and has been a welcome distraction in very difficult times. We’d like to thank the organisers for all their hard work that has enabled us to take part. We’ve learnt so much and we hope to be back next year, older, wiser and with an even cuter robot. Got to play to your strengths. Thank you also to all of you who followed this blog. I hope you enjoyed reading it as much as I enjoyed writing it.

See you next year.

They think it’s all over…

So, we have eight months after qualifying for this prestigious contest to design and make a robot, complete and film four challenges and make a video showing the technical and stylistic aspects of our warrior robot, what’s our plan? How about we leave about 90% of the work to the last fortnight. Yes, that sounds like a winning strategy, good plan.

With the final submission date less than a week away Team DrumbleDrone assembled at Barnstaple Library on Saturday. We had the whole day booked and we had to film all four of the challenges. With some components still hot from the 3D printer we drew up a plan for the day which gradually slipped further and further behind as we tinkered with code, drank tea and one of us disappeared for an hour or so to visit the record fair. And against all expectation we got it done! We have all the videos of the various challenges in the can and we had the best fun along the way.

We can’t show those videos until judging is over and the winners are annouced so I’ll post those in a future blog but here are a few pictures and videos of the day. The final challenge was the DIY Obstacle Course when we went all out with mazes, see-saws, rough terrain and perlious rope bridges. Sorry there’s no footage of this to show today, I couldn’t film any as I was busy dressed as a daffodil and swinging a predatory duck on a string.

And here’s what DrumbleDrone sees.

Finally, I’d like to thank everyone who reads this blog. This will be judged as well and while we would like to win, the writing of it has been reward enough. Thank you too to our international readers! I don’t know how you found us but here is a list of all the coutries represented where we have followers. Fingers crossed now for the judging and may the best team win. No, actually could we win please?

Float like a butterfly, shoot balls out your bum like a bee

Is it time to panic?! Is it?!!!!

No, we’re all calm here. Yes the deadline for final submission of the videos for judging is only a week away and no we haven’t nearly perfected any of the challenges but we work best under pressure. We’ve set aside the whole day tomorrow to meet at the library and get everything done. I’ll let you know how that goes…

In the meantime here are a few updates on each challenge.

Feed the fish

You may remember that we came late to this challenge, inspired by a video of a rapid-fire nerf gun. We had a few technical difficulties with that one, simple stuff like bullets jamming, concussion, losing an eye, so we have opted for the safer nerf ball launcher.

Here’s a video of it in action

And here it is mounted on DrumbleDrone. It’s rear mounted because the thingy that looks like a jaw and picks up bricks for the other challenge is going on the front. This looks more like a sting so obviously it has to go at the other end. Who wouldn’t want one of those on their bum?

The following pictures will give you an idea of the sort of success rate we’re getting at the moment.

Early days

Tidy up the Toys

Not much to report here other than a new brick grabbing jaw as shown in the picture. This one has a lifting mechanism. Ooooooh! And it’s blue. Ahhhhhh!

Up the Garden Path

We have this running quite nicely now and DrumbleDrone only occasionally gets the urge to trundle off and disappear under the sofa. The pictures give you a better idea of what he sees and even a bit about how he thinks.

Technical alert, clever stuff coming.

The top left shows the original image from the Pi cam. The top section is stripped off first, then the image is blurred and converted to grey scale (not shown). This is then put through Sobel edge detector (top right). The image is then sliced horizontally with each slice being approxinately 1/4 track width high. Each horizontal strip is then collapsed down to single row of pixels, averaging the brightness in each column of pixels. DrumbleDrone then runs a peak detection algorithm on this which finds the location of the brightest peaks. These are marked as coloured bars on top of the original image. Finally the peaks are processed from the bottom slice working upwards, first labeling them as light to dark or dark to light transitions (ie most probably left or right of track). Then moving up to next layer the peak is selected which is nearest the lower peak of the same type (left or right). These peaks are marked red for left or green for right (port and starboard colours). The remaining peaks are shown blue. A fork in the path is then identified as port and starboard bars diverging.

Still with me? Well done.

That’s all for now but there might well be more blogs coming so keep your antennae tuned.

We’re Going on a Shed Hunt

Those pesky gnomes have somehow managed to re-arrange the garden path and now our trusty robot can’t find the shed. Your mission DrumbleDrone, should you choose to accept it, is to navigate the tortuous twists and turns of the cunning new path and reach that long lost shed where robot bee nirvana awaits you. This message will self destruct etc etc.

Full instructions for this challenge can be found here but to cut to the shed hunt, the new path looks like this.

Apart from the sorry lack of plants in the garden the first thing you will notice is that the path branches at various points tempting our poor DrumbleDrone into dead-ends that will confuse him and waste valuable time. For this is a timed mission and he has to get to the end in under five minutes.

There are a number of ways to approach this challenge but the one that gets us most points is to navigate using a camera. And it’s all about the points.

Here is DrumbleDrone with the camera mounted at the front, raised up slightly to give it a better vantage point for the path ahead. The more observant of you will also notice the smaller wheels fitted here. DrumbleDrone does tend to eagerly race away and early tests showed that slow and steady wins the shed in this challenge, otherwise he just races past a junction before he has spotted it. Too hasty. Smaller wheels equals shorter circumference and less distance travelled for each rotation of the wheel. A genius level solution, brilliant in its simplicity.

A test garden made of black tape on canvas looks like this.

And with simple edge detection enabled it looks like this, dark and edgy, literally!

But how will DrumbleDrone know what is path and what is the weed-patch that will choke and entangle him? Well, we’re using HSV for colour recognition as we are for the Tidy up the Toys challenge as explained here and the high contrast of black on white is easy to distinguish. DrumbleDrone then takes a slice of the image ahead of it and puts in a marker to show the boundaries of the path. The advantage of this method is that when the green marker posts begin to get further apart DrumbleDrone knows he is approaching a junction. I’ve got to say, the simple solutions really are the best.

Test runs show that this works perfectly. Time to make the official path which must adhere to accurate competition dimensions. We considered using a vinyl cutter to make a stick-on path but in the end decided that analogue sometimes beats digital. Here is a picture of Mitch using his grandfather’s technical drawing instruments to mark out the course. He taught woodwork and drawing a century ago. Mitch’s grandfather that is, not Mitch.

The path itself is made of black tape and a hair dryer helps ease it into shape and makes it stick.

Finally DrumbleDrone is go.

And there you have it, DrumbleDrone’s view as he follows the path all the way to the shed. Or is it me walking around the track holding my phone at ankle level pretending to be a robot? You’ll just have to wait for our competition entry to find out.

Eat Nerf Bullets, Fish

In a late and thrilling turn of events, the Feed the Fish challenge has sneaked back into our our plans for world robot-wars domination. The rules are here but to summarise for impatient readers there are two options for feeding the fish. The easy way and the hard way. The easy way requires pushing balls into the base of a structure which, stretching the imagination, is known as the fishbowl. The hard way is to fire projectiles into the top of the fishbowl. Oooooh!

In the early days of assembling our crack team of mad scientists we had a team member who took the lead on this but he had to pull out to concentrate on his studies. It was a blow but we soldiered on, wounded but not defeated, cast down but not destroyed. We assumed we would have to lower our sights and use the remote control to simply shunt the balls over the line for a mediocre display with a mediocre score.

Then we saw this…

Reader, we were inspired. The fish were either going to get fed or blown out of the water by a bumble bee shaped robot carrying a Nerf launcher on its back.

The Nerf launcher we found is a Hackster project by someone going by the unlikely name of Little French Kev. Full details can be found here and it includes everything we needed, video build guides, all the 3D printing files and parts list. We only need the magazine and firing part of the launcher, as we already have an existing pan and tilt mount. Eagerly we set about printing the required parts. 

Apart from producing the same half twice by mistake it was a straightforward print, free from drama and disaster and before long we had our assembled missile launcher ready to test.

The first firing test was carried out during a weekly team Discord video chat, in between discussing the challenges, COVID 19 and the weather. For the first test the motors were wired up in parallel using some solderless breadboard and a 4 x AA 6V battery pack for power. One of the DC motors proved faulty but luckily it was bought as a pack of four so we had a replacement. The motors are quite noisy and it sounds appropriately like an angry bee! The design is simple yet ingenious. The projectiles (fish food) are mounted in the magazine, they are the fed to the rollers and when they engage they are whizzed through and out at high speed like this…

Success! Sort of. It’s not quite like Little French Kev’s rapid-fire killing feeding machine just yet. We have some tweaking to do, experimenting with different projectiles and adjusting the loading arm but we’ll get there.

Getting the mechanism to work is one thing. We also need to mount it on the DrumbleDrone and control it with our PS4 controller. The Pi itself can’t power the DC motors so we need to mount the 6v power pack as well and in order to control the motors we tried using an L9110 H Bridge Motor Driver Board. It sort of worked but didn’t seem to provide enough power so we then tried a MOSFET DIY circuit to replace the motor driver. A MOSFET is a Field Effect Transistor that allows us to use a digital pin on the Pi to switch a larger power source on and off and we wired it like this. Elegant and beautiful in its simplicity.

After wiring the diode the wrong way round and getting some alarming blue smoke we eventually had success! The PS4 controller now operates the MOSFET circuit to turn the motors on and operate the launcher. There’s clearly a lot more to be done but hopefully soon those hungry fish will be munching happily on tasty Nerf bullets.

I’ll leave you with a picture of a very excited DrumbleDrone trying his new toy for size. Until next time everybody. Thanks for reading.

DrumbleDrone gets a Makeover

Meet DrumbleDone in his previous incarnation and not looking much like a Bumble Bee. This robot was first used in Pi Wars 2018, entered as a school’s team. Since then the robot has made several appearances at Barnstaple Library (The home of the Barum Jam) and this is how it looked as a house robot during the Droid Warz event on Star Wars day 2019 at the Library. The jagged jaws shown here were for popping the opponent’s balloon and the four eyes was because that’s how many googly eyes we had. They were happier and simpler times. It was a great day and here’s a shot of me with a very special guest. The picture doesn’t show it but the Storm Trooper was wearing slippers because even minions of the dark side who can’t shoot straight deserve comfy footwear.

But now, the robot will need to undergo some major modifications and be re-designed to suit its new identity. Today we will considering the software and hopefully soon there will be another blog or two about design and cool attachments like grabbing claws and nerf guns. A heads up for the more general reader, it might get a bit technical. Don’t worry, just let your eyes glaze over and click like at the end.

The first task is to update the software because the old SD card was running a version of Raspbian Stretch from 2018. A fresh download of Raspbian Desktop Lite was flashed to a new 32GB Sandisc SD card using the Raspberry Pi Imager. Details showing how to do this can be found on the Raspberry Pi Website here.

It soon becomes apparent that a robot can’t be dragging a monitor, keyboard and mouse around behind it so to allow access to the Rapsberry Pi from a laptop we followed this guide on Tom’s Hardware. In short, after flashing the new OS to the SD card you then create a blank plain text file on the Pi root directory called ‘ssh’, ensuring that the file has no extension. This forces the Pi to enable ssh (Secure Shell). After doing this you need to create another plain text file called wpa_supplicant.conf. This file should then contain the details of the network you wish your pi to connect to, enabling you to ssh into it. Easy as Pi. We did have some trouble doing this and after trying several times realised that we had spelt supplicant with only one ‘p’! Eventually, having connected to our Pi we were able to set up VNC (Virtual Network Computing) to share the Pi’s desktop for full access to it.

The next task was to install OpenCV, a library of functions which lets DrumbleDrone see and recognise objects. We did this using Adrian Rosebrock’s guide here using pip, Python’s own package manager. We ran into some difficulties with this but nothing we couldn’t solve after a bit of faffing about and consulting other guides. The biggest problem we found was the install would hang at the last section. We thought it might be a dropped connection through ssh but soon eliminated that as the cause. Finally we learned from some very helpful people on Discord that the last section is very memory and processer intensive. Running a htop command (new to us but we will definitely use it again) it showed that the 100mb swap file was maxed out. We increased the size of the swap file to 2gb, started the install again and left it running over night. Problem solved!

The final bit of software we installed was Approximate Engineering’s Input Library which is required to connect our PS3 controller by Bluetooth and full details of how to do this can be found here.

That’s all for now. Hope to be back soon with tales of shooting nerf bullets at fish bowls.

Happy New Year!

Welcome back and a very belated Happy New Year to everyone! Sorry it’s been so long since the last update. It’s not that the team haven’t been busy because they have, they’ve been beavering away in their labs, hardly pausing to eat Christmas Dinner. No it’s me, I’m the idle one.  

The first piece of news is the deadline for entries has been postponed. We were looking at March for final submission of our videos of DrumbleDrone in action but because of the continuing Covid situation this has been put back to July. Is that a massive disappointment? Where we raring to go with everything ready? Or is it secretly a bit of a relief? Well our leader Johnny Alpha’s immediate response was to warn us to stay focused and no slacking which is a shame because slacking is what I do best. All I can say is come July, DrumbleDrone will be even more ready than it is now. 

In other news, we all enjoyed and were truly inspired by the Pi Wars 2021 Conference that happened this weekend. There were two whole days of talks and demonstrations on all things robot. Some of the entries were showcased which has certainly made us want to raise our game. Blimey they were good, and hopefully in a different category to us! But the best thing was the real sense of community and collaboration with people happy to share information and advise others. You don’t find that in most competitions. So a big thank you to the organisers. 

The talks should be coming online soon for anybody to watch so you should check out the Pi Wars YouTube Channel: 

And finally I’ll leave you with the trailer to the 2020 competition so you can get a feel for what the event has been like in previous years. 

It’s time to Tidy up the Toys

We’re still busy busy busy here at the Barum Jam Collective trying to get our trusty DrumbleDrone to do what it should be doing and we’ve made quite a bit of progress on the Tidy up the Toys challenge. The aim of this one is for the robot to identify three coloured 50mm x 50mm cubes (red, green and blue) in a 1500mm x 1500mm arena, collect them and deposit them in a target area. Easy really. Collecting and depositing can be done either by remote control or autonomously. We will be developing an autonomous method because we enjoy the pain and because we can earn more points this way.

In order to tackle this challenge autonomously we need to delve into the fascinating world of computer vision (you at the back, wake up!) using Python and OpenCV. After a bit of research we concluded that the robot could be able to detect the object in two ways:

            1. Using OpenCV Contours, to identify object by it’s shape

            2. Using colour detection, to identify the object by it’s colour

As the colour of the arena floor and walls can be plain (white, grey or black), identifying the object by its colours seems to be the easiest way and after more research it was found that the best method for identifying colours is using HSV.

The first task was to find the HSV value for the colours of the objects which we achieved using a script with slider bars to adjust and display the levels. Once we had a working HSV levels script, it was then tweaked to re-calibrate the detection where lighting affects the colours. Using the identified HSV values we set about working on a script to detect a coloured ball (because we haven’t got any cubes!) Various methods were tested resulting in a draft script which detects all three colours and draws a bonding box around each identified object as shown in the picture here. Hooray!

I could show you these scripts but then I’d have to kill you. Or get DrumbleDrone to.

It’s all coming together nicely and you can see DrumbleDrone in action chasing the ball here on the Tidy up the Toys page.

That’s enough for now. Next time we might talk about grabbers.

Meet the DrumbleDrone

Hi all. Today I’d like to introduce you to the most important member of the team. The four main Pi Wars challenges all require a robot to perform the fiendishly hard tasks and so here he is, our very own DrumbleDrone the robot!

In fact, we have two robots to test on but for the final events we will have assembled one mighty warrior robot with all the superpowers needed to complete the challenges. He’s based on the very brilliant MonsterBorg Chassis as produced by PiBorg and the one pictured is a re-purposed version of a PiWars 2018 entry.

So far DrumbleDrone is made up of the following hardware:

MonsterBorg Chassis

Thunderborg Motor Controller

4x High-Torque 300 RPM metal geared 37mm motors

105mm / 4 inch diameter off road wheels (To be changed)

Raspberry Pi 3

Raspberry Pi v2 Camera

UltraBorg Ultrasonic and Servo Board

HCSR04 Ultrasonic Senors

He is also currently sporting a body made from the underside of an old MacBook and four googly eyes. This look is so 2018 and so the Technical and Artistic team headed up by Stevie Wong will be giving him a complete makeover before the big day. I should point out that DrumbleDrone is an old west-country dialect word for a bumble bee so expect something in black and yellow stripes.

We have one problem in that the stock wheels make the robot slightly wider than the permissible dimensions, so they will need to be changed. We do have a second set of wheels that will be OK but we are currently researching and searching for a set of suitable Mecanum wheels as they would afford greater manoeuvrability. And look so cool!

We hope to have some footage of the DrumbleDrone in action soon so check back regularly to see how we are getting on

For more detail of the particular challenges check out the Challenges page on our site. Thanks for reading. See you soon.

Team DrumbleDrone are Go!

Hi all.  

The euphoria of getting accepted into Pi Wars is finally wearing off and it’s time to do some work. It’s a real team effort here at The Barum Jam Collective with each member bringing their finely honed skills to the picnic so check out the Meet the Team page to see who’s who.  

Obviously things are a little different at the moment when it comes to doing stuff together but we manage. We’ve only had one zoom so far but more may be necessary as the need to collaborate in real time increases. Otherwise, we have a lively Discord hang out going full of banter and The Barum Jam Collective GitHub where we share our top-secret code and files.  Any changes at GitHub and a notification is near-instantly sent to the corresponding Discord channel. Clever. We also have a twitterbot extracting tweets with the hashtag #piwars and feeding that into the Discord so we are constantly up to date with how the wars are trending. Big shout out to team legend Shybeega who has organised this. 

That’s it for today but there will be a lot more actual content coming out in the next few days so stay tuned and subscribe if you haven’t already. 

 See you soon 

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