All Packed!

We have spent every evening this week checking and re-checking the robot and his code. Each challenge has its own settings and we are using different batteries in different challenges too(a balance of control vs. speed). With the exception of one challenge we are now confident that we can do the best we can. We’ll make a decision about that one on Sunday…


KEITH 3, KEITH Evo and KEITH (the original 2014 PiWars entrant)plus a few spares, tools and chargers are all packed up. We’re ready for an early start tomorrow morning and the 150 mile run down the A1 to Cambridge. We are now looking forward to the weekend (as opposed to being anxious about it a week ago!). It will be good to see old friends/adversaries and meet new people too. One of the lovely things about PiWars, and the Raspberry Pi community in general, is the friendliness and willingness to help. As Dave (with Xbot) says, everyone who has produced a robot and makes it to the competition is already a champion. Prizes are great, of course, but I hope that all of the new teams take home the desire to do it all again, as we did in 2014 and 2015.

Finally, before the competition, a big thank you to Mike, Tim and their merry band who all work so hard to put this event on. If they are looking frazzled over the weekend, make sure you show your appreciation!

See you there!

Andy and Harry

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Mostly Harmless...

Tonight was the moment of truth. When we got home from school/work we spent about an hour reinstalling the Pi and the control circuits to KEITH3. A deep breath and we plugged the battery in. Lights came on and things that needed to flash flashed. Harry ran his test programme to trigger the appropriate GPIO pins and made various LEDs come on and the solenoids worked! We then tentatively checked the motor control circuit and things moved! One track went the wrong way which was quickly solved. Hooray!!

Insides Insides

There is now a pile of work to do to make sure things do what they need to when we want them to and that we can actually make KEITH3 have a go at all of the challenges. There is still time for things to go wrong, but we’ve been here before and made things work. There may be a few late nights this week!

Here are a couple of images of KEITH3 Mostly Harmless looking pretty smart!


And here is a family portrait!

Family Portrait Family Portrait

We will continue to post up to the competition and report on how things go on the day. We are really looking forward to meeting old friends again and making new ones. It is a pleasure and a privilege to have been part of all of the PiWars contests and seen it grow and grow. This year Harry will be doing a show and tell on Saturday with the KEITHs and I will be doing a spot of judging, so watch out school teams! Whatever happens on the day, we will have had months of fun putting our bot together and will have a blast trying to make him work on the day. Having seen the other competitors in our category, it’s not going to be easy…

See you there!

Andy and Harry.

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Just Keep Swimming!

The new Pi arrived and was fitted, but we had no power to one motor and the other motor only ran in one direction. KEITH Evo used the same chips so we did some comparisons of resistance across connections and discovered that our new chips were not working. So, deep breath and we ordered new ones. They arrived today so we spent the evening removing the old ones and putting the new ones into the circuit. We’ve tested most of everything else now, so we’ll plug everything back together tomorrow and see what happens. If all else fails then KEITH Evo may need to come out of retirement!

I have finished the chassis of the robot. I tweeted a sneaky peek and was suprised at the comments and numbers of likes it attracted. Nothing viral, mind you, but I don’t normally attract that much attention! This is what KEITH3 Mostly Harmless looks like. He might not work at the moment, but he is probably better looking than his predecessors!


Hopefully we’ll get one more post in before the deadline and then it will be just a week to go! Help!

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We’ve had a good day pulling the last pieces of KEITH 3 together and were happily testing connections to gpio pins. Harry asked me to short out a resistor on one circuit and I touched a wire to something else… A puff of the old magic smoke and some unprogrammed flashing of LEDs ensued before I killed the power. we extracted the Pi and Harry checked a few things and declared it deceased.

A quick on-line hunt and we found that our Amazon Prime membership meant we could get a new one within three hours! Back to testing in the morning…

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Will it All Work?

‘A few hours work to put everything together’ I said… Just a few! However, the long hours drawing everything in detail paid off as almost everything went together as planned. Well, there were a couple of holes that I had enlarged in the wrong direction(!) and I had transposed a wrong and fundamental dimension onto three other parts. The first problem was easily fixed with a drill and a craft knife. The second required a minor redraw and new parts to be cut. I took advantage of the redraw to improve the original just to make everything fit together more easily.

Parts Parts

All components will have been put together in the next day or so. I needed a few new jumper wires which are winging their way from an Ebay seller as I write. As with KEITH Evo, the Pi is now mounted on a hinged tray so that everything underneath can be got at without the need to pull wires.

Spaghetti Spaghetti

We have a single servo, used in two challenges, on the robot. I had hoped to use an attachment for one of the challenges, leaving the parts for the other challenge permanently attached. I have now decided that is too ambitious, so we will swap the servo arm for the two challenges. No great issue, but it has changed the way that the servo is fixed to allow access for the arm change.

Blinky bits are in and working, complete with the obligatory laser in its own custom 3D printed housing. The 3D printer has been hard at work for a few other bits too, but we’re going to keep those under wraps until the competition. We have a new idea for giving our tracks better grip for those challenges that need it - we think just the obstacle course. Having full proportional throttle control means that we can control ‘track-spin’ on other challenges with reasonable ease. The lack of three-point-turn this year (hurrah!) means that we do not need to work out how to turn accurately using the motors, but are using other sensors instead. We think that will make things a little easier this year…

Inside Inside

Underneath Underneath

Tee-shirts have also been designed and ordered!

As soon as everything is fixed in place we will be testing the control and sensor systems. We then hope to have a little time for practicing…

Details Details Details

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The Calm Before The Storm

This time in four weeks we will be reflecting on our performance in our third trip to PiWars. Will it be our last? Harry will be off to university in September learning all about Automatic Systems and Control Engineering or some similar gobbledegook and taking the first steps towards a career doing what he loves - a mix of computers and electronics. I sincerely hope we can find the time to take on KEITH 4, even if it is a long-distance collaboration!

Enough of what might be. We’ve had a couple of good sessions bringing everything together on KEITH 3 and, despite the size of the list of things still to do, I think we are getting there. A marathon session on AutoCad last night let me finish (at 1am…) what I hope is the final set of parts for laser cutting. I just hope our tame tech teacher at Harry’s school doesn’t have a fit. The parts fill nearly three A3 sheets! That said, I keep offering to pay for stuff and get a negative response (and we did use second-hand mdf for the prototype chassis).

CAD Plan CAD Plan

A Few Chassis Parts A Few Chassis Parts

All circuit boards have been constructed with LEDs on stripboard and the motor controller/ switching circuits all on a re-purposed Protocam board, minus a camera. There are a few bits and bobs to put together, but we need the final chassis with the Pi mounted so we can fix wire lengths to (try to) keep things tidy.

Control Board Control Board

LED Boards LED Boards LED Boards

Harry has also produced a few bits and pieces for KEITH3 on his 3D printer. It’s a Tevo Tarantula and considering the kit ‘only’ cost around £200 he has nurtured and coaxed it to produce some very acceptable components. It continues to amuse me that he uses it to print upgrade parts for itself…

We’ve got a few hours work to put everything together. Doubtless some bits will not fit in real life and will need adjusting/recutting. However, once done we will be on with proper testing. Harry’s code is working and hopefully will need minimal adjustments to get everything working together. I think he’s been most tasked by getting some of the ‘extra bits’ to work, but I think we’re getting there. Last year at this stage we hit a wall where nothing seemed to go right. It was incredibly frustrating until we pushed through it and suddenly everything came together. On the day we knew how things worked and, despite knowing that things can and do go wrong, we held it all together. Let’s see how 2017 goes…

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Running Out Of Time!

We have made some progress in the last week or so. We have the new ‘development chassis’ cut and the parts we have are being fitted. Harry needs to get his code in order too…

Last weekend we were invited to go over to Bradford to meet up with a couple of teams based there. One was a team from Bradford Grammar and the other from a code club run by Mike at Exanet (one of PiWars’ sponsors!). Both teams will be competing on the Saturday and both have robots based on commercial chassis. Considering the very limited time they have together to work on their robots, we were very impressed with the progress they had made.

Workshop Workshop

We gave them a potted history of KEITH in his various iterations and shared as much information on the competition as we could. The Exanet team were working on independent movement using a games controller. The Bradford Grammar team had already mastered the connection with a Wiimote and had an ultrasonic sensor working. Harry spent some time with them cleaning up the code and showing them how to iron out the ‘odd’ readings to give consistent distance measurement. They also managed to fit their reflectance sensors for line following and we managed to get some experimentation done to set the separation on them. We finished the session with a race around the track between KEITH Evo and their bot (they were faster on the straights, but KEITH Evo was faster on the bends…). We are hoping to meet up again before the competition when I hope KEITH 3 will be running properly!

Back home we spent a little time deciding how to wire everything up. We finally decided to use a ProtoCam prototyping board (designed by our friend and rival Averageman) to keep things as neat as possible. That board is being put together with motor controllers and transistors to switch LEDs and other components. We are considering how to connect the ultrasonic sensors and, more importantly, how and where to mount them!

Protocam+ on Pi3 Protocam+ on Pi3

KEITH3 (Mostly Harmless) KEITH3 (Mostly Harmless)

As ever, help comes from unexpected quarters. Harry had an interview at a university today and came out with tips on robot control from a computer science professor!

p.s. If this post works, it will be a first for this 53yr old without help from his 17yr old! There may be hope for me yet!


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New Clothes

Our new tracks and running gear arrived from China in double-quick time and as soon as they did we were straight on to designing a rough chassis to fit them to and to get testing. This was done in double quick time and the parts were cut by the Tech teacher at Harry’s school. A happy evening with tacky pva glue, clamps, a spanner and Allen keys led to a sleeker version of KEITH than we had previously seen. The wheels from China consist of two stainless steel ‘rims’ with spacers between. The drive cogs bolt to hex hubs which fit the motors. The free-running wheels have bearings on each side and run on bolt axles. I modified the hex hubs to reduce the overall width of the assembly (deft use of the Dremel to chop out unwanted bits of brass!) to ensure that everything fits within the 225mm width limit.

Smart Wheels! Smart!

The tracks, as we feared when we ordered them, are a hard plastic. They are manufactured for one of the radio-control tanks on the market and work extremely well on soft surfaces (carpet, dirt etc) but they slide on hard smooth surfaces. Not what we want for PiWars! That said, they are better than the Vex tracks used last year in that respect. We have a few ideas about how to add grip and will be trying those out in due course.

We installed the Pi, the makeshift motor drivers and RC receiver then plugged in one of our new LiPo batteries. Harry fired up the code and off we went! Wheelspin (trackspin?) on the kitchen floor and drifting round corners was fun but perhaps not as precise as we need! Turning on the spot is very fast and the prototype ran well on carpet too. All very promising. The kittens were very interested and either followed it or just sat in the way. No doubt they will learn to interfere properly as testing continues…

Work on the drawings for the competition chassis is now advancing. Changes required from the initial prototype have been made and the skittles-flicker has been tested. Sensor locations have been sketched in and ideas for the golf challenge attachment have been drafted out and would appear to be workable. The aim here is to fit a single servo into the front of the robot that will do two things for different challenges, but without needing different code or any changes in electrical connections. That was a lesson learned in the first PiWars when KEITH did not do as well as wanted when we relied on attachments. Last year KEITH Evo had everything built in. That proved reliable, but we had all sorts of difficulties in fitting everything in and making it work practically.

Harry has tested his glycerol-based ideas and they look positive. It now falls to me to try to hack various bits of hardware without breaking it :-)

We are also really pleased to have been invited to a workshop on 11th February in Bradford where we will meet a number of local PiWars teams. The aim is to swap notes, hints and tips with KEITH, KEITH Evo and possibly the prototype KEITH 3 (Mostly Harmless) strutting their stuff!

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New Year Blues

Long time no see! Happy New Year to all readers. As of today, it’s exactly three months to go until PiWars 2017!

KEITH 3 has been sat in his box for some time now waiting for some action. Harry has been concentrating on his A Levels and university applications, so KEITH has taken a bit of a back seat. I’ve spent some time on AutoCad tweaking dimensions here and there to improve track fit and add a few holes here and there, but nothing really significant.

So, the Christmas holidays arrived and for the first time ever we were spending it at home - just the four of us - giving an ideal opportunity to set a few things up and do a bit of testing. Harry put together a motor controller board using a breadboard and a couple of H-bridges (big enough to cope with stall current on the motors this year!) together with a UBEC to provide a stable 5v supply for the Pi.

Harry had obtained a cheap Chinese arduino-like board to use to translate the radio receiver signal to something the Pi could use. Initial tests of that were not good, until he discovered that the processor was running at 1/8 full speed because of a default setting. The addition of a little code reset that to allow it to run at full speed and the problems were solved. Oh I wish I knew what he was talking about, sometimes…!

We plugged everything together and clipped on the battery pack. With KEITH sat on a tin of bamboo shoots we pushed the joystick forward. Harry made a few code adjustments to get things running in the right directions and off we went. The first problem was radio reception. This had been anticipated… our new kittens had found the orange aerial wire hanging out of the box and had promptly shortened it by about two thirds! That will be sorted in due course, but for the purpose of the testing we just made sure the transmitter was kept close.

We have used motors that are similar to those we used in KEITH Evo, except that they are geared to run faster. This does reduce torque, but we wanted to make sure that KEITH 3 was quicker than Evo and we had had no problems at all last year. In a straight line KEITH 3 was great. Much faster than Evo, so the first box was ticked. However (actually it was HOWEVER), he could not turn! Our fab new grippy wide tracks, intended to avoid the loom-band issue we had with KEITH Evo, were simply too grippy. He was better on carpet, but still not good - and the events are on a smooth surface anyway.

What to do? Bigger motors, we reasoned, would need more current and batteries would become an issue. We also thought they would add significantly to the cost. Swap the tracks for wheels? This was considered only long enough to remember that KEITH 3 is an iteration of KEITH and KEITH Evo, both of whom are tracked robots. Different tracks? Having spent hours finding the tracks were already have we were a little reluctant to do this. We were not keen on using the Vex tracks we used last year and the little Tamiya stretchy tracks used on KEITH would not be any good on a larger robot. However, a little searching on Ali Express identified some potential options and new tracks, cogs and idler wheels have now been purchased and are winging their way from China as I write. They will necessitate a complete redesign of the chassis but they should allow more space.

On a more positive note, I have acquired a couple of solenoids and successfully tested a flipper system for the skittles challenge :-)

Harry is still collecting ‘things’ and won’t tell me what the bottle of glycerol is for. He assures me that it is safe and has something to do with a little pump and some silicon tubing…

More soon!


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KEITH 3 (Mostly Harmless) will be at PiWars 2017!

Well, we’ve had the email from Mike and Tim to say that Team Keith has an entry. We will be competing on Sunday 2nd April in the Pro/Veteran class! Not sure about ‘pro’, but we are definitely veterans of the competition…

As you can tell from the title, the next robot will be called KEITH 3 (Mostly Harmless). That’s the result of hours of deliberation – honest! KEITH 3 will, once again, be tracked and use wood (or MDF) as the main chassis material.

New tracks - closeup

New tracks have already been acquired and an initial chassis has been designed and cut. The tracks have very little give/stretch in them and the initial design left them a little tight. The CAD was altered and new parts cut. True to form the tracks are a little loose now, but will work for our initial testing. Harry has started to gather other parts. A Pi3 will be at KEITH 3’s heart and we will use radio control again for manual control. That method gave absolutely no problems last year and it seems sensible to do the same again. A power source needs to be decided on and the motors need testing to ensure that they will do what we need them to.

We are hoping to make a trip over to Bradford in the near future to see the Bradford Grammar team. The 2014 KEITH has been brought out of hibernation. His distance sensor is not working (the original was pinched for KEITH Evo when his failed), but we have Wiimote control, flashing LEDs, line-following and a working golf attachment. Harry is very critical of his code from 2014!! KEITH Evo is also up and running.

KEITH, KEITH Evo and the KEITH 3 prototype chassis!

We have some ideas about the various challenges, but we will start to develop those once KEITH 3 is moving. Watch this space!


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KEITH 2017 - What Now?

So, PiWars 2017 is on the cards. The entry process starts on 1 August and we will definitely be putting an entry in. Will we be successful and be allowed to defend the title we were so proud to win last year?

Harry, now 17, and I, now a bit older too, have talked lots about the next competition. We love the new rules with the different team classes all linked by a single maximum robot size. The challenges look good too – it is really great that Mike and Tim have taken on board lots of the things that we, as competitors, talked about last year. This competition just keeps getting better!

As last year, we want to build on our experience. KEITH will rise again – tracks, plywood, home-made controller circuits, flashing bits, lasers, plywood. We had huge success last year using the old radio control kit, so we may well replicate that again. We will be doing some serious work on how to balance motors for accurate autonomous control and are really looking forward to seeing how we can try to beat the maze.

Attachments will be back! KEITH Evolution was self-contained and the cannon for the skittle challenge made so many other things a compromise in terms of space. We have some ideas…

The big question is ‘What will the new bot be called?’ KEITH Evo II? KEITH the Next Generation? SuperKEITH? (!). We need to work on that…

One nice thing about PiWars 2017 is that it will be over two days - school teams will take day 1 with other teams on day 2. We have had some contact already with a Leeds School who have a team of young people who are keen to enter a robot. They have met KEITH Evolution and played with him. They are working on ideas and making their robot move and sense the world. Harry and I would like to be able to keep in touch and swap notes as we go. It would be great to support them if they get an entry. We also thought it would be good if some of last year’s competitors could bring last year’s robots for show and tell/demonstrations on the Saturday – aimed at helping the school teams. That may be something to talk to Mike and Tim about later in the year.

Watch this space. We’re already researching materials and sketching configurations for the chassis. Entry or not, the next iteration of KEITH may come to life regardless!


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