r/arduino • u/Oli_Vier_0x3b29 • Aug 18 '26
Look what I made! The Dot-Bot @ the Maker Fair 2026 in Hannover Germany
5 years ago, I started the project Dot-Bot with u/s3lect. It is a large scale wall plotter project that draws with actual spray cans. Last weekend, we showed it off for the very first time outside and in front of a live crowd at the annual maker fair in Hannover Germany. Here is one of the murals we spray painted over the course of the event. Fortunately, the Dot-Bot proved to be extremely resilient. During the 3 days it was installed on the wall, it got torched by the sun and soaked from the rain multiple times. However, it never let us down. We definitely had a blast talking to a ton of fellow makers and interested visitors!
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u/Spamonfire Aug 18 '26
Is it possible to install at any wall or only this specific setup?
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u/Oli_Vier_0x3b29 Aug 18 '26
Any wall works fine. The software can handle any canvas & bot setup, with 2 or 3 motor stations depending on the width of the wall and the expected forces
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u/Jutboy Aug 18 '26
Why Stanley?
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u/Oli_Vier_0x3b29 Aug 18 '26
They were the main sponsor of the event. Also, their social media guy said they would share our project if we would do a mural for them. And this was the only mural where we filmed the entire process from start to end. Thats are the reasons :-)
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u/Jutboy Aug 18 '26
Awesome project. I'm glad it worked out so well! I would have been super stressed haha.
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u/Oli_Vier_0x3b29 Aug 18 '26
We were quite stressed :D first time with people watching us do our thing, and also constantly taking pictures of us and everything we did :D
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u/fatcatfan Aug 18 '26
Brings back memories of programming the "turtle" on an old Apple //
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u/Oli_Vier_0x3b29 Aug 19 '26
Sounds like you're a tiny bit older than I am, because I do not know what turtle programming on an Apple II means. 🙂
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u/s3lect Aug 19 '26
Actually there is a turtle toy gallery that I really love as inspiration for generative art https://turtletoy.net/turtle/browse/love/ we may have even printed one of these at some point
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u/fatcatfan Aug 19 '26
Specifically on Apple there was a programming language "LOGO" that allowed you command a small triangular "turtle" cursor to plot on the screen. Kind of like a pen plotter. Tell it which direction to turn, how far to move, and whether the "pen" was up (to move only) or down (to leave trails).
What you've created here is of course more technical, incredibly impressive, and not really quite the same, but that's just what came to mind when I saw it at work.
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u/andypiperuk Aug 19 '26
fwiw Logo pre-dated Apple by 9 years :-) https://en.wikipedia.org/wiki/Logo_(programming_language))
I was probably using it in a similar era to you, only on Acorn computers in the UK 😄
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u/fatcatfan Aug 19 '26
You're right of course. It's been a good while. Apple had their own Logo dialect apparently.
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u/Oli_Vier_0x3b29 Aug 21 '26
Yesterday I really got into those turtles and there is so much good stuff for plotting, I am kind of sad I did not know about this before the fair
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u/GothicTracery Aug 19 '26
Yay! I did a very similar project in 2020: https://youtu.be/jOpgvW7aIhQ?is=pgXMfTdXuoi11Qak
The biggest challenge was controlling the spray can, we ended up spraying lines of dots.
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u/s3lect Aug 19 '26
This is very nice. We were pleasantly surprised how many makers we met that also started similar projects. Maybe we need a spray bot makers conference some day :D
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u/Oli_Vier_0x3b29 Aug 19 '26
Oh wow, this is super cool. This is actually the first time I see your project. Very well done 🙂 Indeed the biggest challenge is having enough speed so you can keep the can pressed without paint staring to drip. Our bot can go even faster, but the best results we get when we paint slowly with as little pressure as it needs for a steady stream of paint to come out of the can. In the very beginning of this project, when we were not so far with the control software, our project could also only do dots, hence the name Dot-Bot 😄
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u/GothicTracery Aug 29 '26
Took me a couple of weeks to build, including integration with the wheelchair. How did you manage to stretch it to 5 years LOL?
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Aug 18 '26
[removed] — view removed comment
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u/Oli_Vier_0x3b29 Aug 19 '26
Yeah go ahead. The smaller ones are really easy to build and a lot of fun to play around with. :-)
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u/coleskidmore Aug 18 '26
that resilience throgh the rain and sun is the real flex honestly
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u/Oli_Vier_0x3b29 Aug 19 '26
Thanks. I was also surprised even my router that got soaked survived. But I'm a bit afraid of the long term effects. I use coil springs to keep tension on the belts. If they start to rust it will definitely degrade their lifespan. Let's see.
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u/dekbanna Aug 18 '26
Really curious how you're handling positional accuracy over that scale, especially outdoors where wind and temperature swings could throw off cable tension. Any calibration routine between motor stations, or does it self-correct on the fly?
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u/Oli_Vier_0x3b29 Aug 19 '26
Wind and temperatures are not a big factor. Since the gondola is constantly losing mass during spraying, that affects the overall weight much more than the temperature swings. Also, we used GT2 belts. They are designed to be precise on CNC machines. They have a very low coefficient of thermal stretch. But yeah, we do have to calibrate the motors every time we power cycle them. This is fairly easy, to be honest. I build a companion app that I can open on my phone and look directly through the stencil of the gondola onto a point that we marked on the canvas. In this case it was a screw in a board that we precisely measured against the zero point.
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u/Valuable_Fortune1982 Aug 19 '26
Stuff made here did this like 2 years ago was epic.
Wonder if he did it "first"?
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u/Oli_Vier_0x3b29 Aug 19 '26
We started this project before he started his. Also, both projects use a completely different approach to positioning. His project got a lot of wobble to it, so he opted to only draw dots instead of vectors. But yeah, both projects are cool in their own unique way.
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u/s3lect Aug 19 '26
Fun fact: when stuff made here created his bot he got to the state where he could draw dots with his bot, this is also where our bot comes from thus "Dot-Bot" by now Olis work has progressed and we can draw smooth curves and straight lines.
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u/Mysli0210 Aug 19 '26
Awwww i was at the faire and completely missed it!
That is so cool!
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u/Oli_Vier_0x3b29 Aug 21 '26
We heard that so many times already :-( We were outside right between the two big halls, really close to the stand of Stanley. But turned towards the side no one was paying attention to. Hope the next time we get more lucky.
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u/Mysli0210 Aug 22 '26
Yeah i could sorta figure out the location from the video. Next time i'll be sure to look there and other places like it.
What they ought to have done, was to place you up against the opposite wall (the one closest to the large hall, just to the right of where the ELV booth was or a similar place)
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u/Quicker_Fixer UNO, Nano, plain ATMEL, ESP8266 and ESP32. Aug 18 '26
https://giphy.com/gifs/3otPoIRRO0TlyZAuT6