Introduction: Bikelangelo: the Graffiti Maker Bike
On this Instructable, I'll share all the resources you will need to create your own Bikelangelo and become the coolest protestor of your town.
It’s inspired in the classical persistence of vision (POV) projects, but has been modified to control electrovalves instead of controlling LEDs. I implemented a simple system with some magnets to coordinate valves' speed with the speed of the bike. Also, I added a Bluetooth receiver so as not to depend on the computer to send the sentence to be written.
Supplies
I’ll divide the process on three main parts:
- Electronics
- Paint tank and painting system
- Structure
Bill Of Materials:
Electronics:
- Arduino nano.
- Hall effect sensor.
- Bluetooth module (HC 05).
- 8 channel relay module 5v.
- 12v battery.
Paint tank and painting system:
- 7x Electrovalves (12v).
- 8x bike valve (recycled).
- 7x garden sprinkler.
- PVC tubes and joints, I used a 160mm as main tube for the tank.
- Air pump.
- Flexible tube.
Structure:
- It’s up to you. I used PVC tubes but I think that's not the best option. I recommend making it metallic, but you can use any material and dimension that fixes to your needs.
- PVC glue.
Step 1: Building the Paint Tank and the Structure
First, I made the paint tank. This part is so important and you should glue it carefully, because once you glue it together you’ll not be able to fix it.
I don't have sketches of the design, but you can get the idea from the video above so you can adapt it to your needs.
The same happens with the structure. You can get inspiration from mine, but there are no sketches so you will also have to adapt it to your needs.
Step 2: Electronics and Arduino Sketch
You can download the arduino sketch and the wiring diagram from my github profile:
Step 3: How to Use It!
First of all, you'll need to fill the paint tank with paint or water to the half of its capacity. Then close the tank and pump air in to create the pressure.
Once the mechanical part is ready, you must send the sentence you want to write via "Serial Bluetooth Terminal" app. You have to end the sentence with a '&' to tell the Arduino that's the end of the sentence. Otherwise, it will stay waiting for it. When the Arduino receives the sentence, it will let you know by turning on a LED on the pin 13.
After this, you just have to start cycling and the machine will start painting automatically.
Good luck!
I'll be glad to help you if you have any doubt!

Participated in the
Arduino Contest 2020
21 Comments
Question 2 years ago on Step 2
Hello
I would have wanted to make your printer so I bought all the electronics and cabled everything as on your diagram then I uploaded the code and it does not work the relays does not work the wall sensor remains on when the magnet passes to operate the wall
I must modify line 58 by passing it to INPUT the sensor reacts but not the relays for info
my arduino nano has the old bootloader can you help me please
Best regards
francis
Answer 2 years ago
Hi Francis!
Could you give me more information?
What do you mean with "It does not work? It doesn't work at all or it works wrong?
Which is your Arduino/Electronics level?
Have you tested the components separately?
The problem with the hall effect sensor sound more like a componen issue than a code issue.
I'm looking at the code, and I've notice that I use the word LED instead of VALVE. So don't mesh with that.
On the other hand, the pinMode defined on the line 58 is the LED indicator. It's aim is to turn on when the Bikelangelo receives the message to write down.
Reply 3 months ago
Hi, I am having the same problem. Checked all the components, but no reaction of relay module.. According to the fritzing drawing the signal from the sensor goes to pin D13, but the code says "attach Interrupt 0" (line 62) which would be D2 or am I wrong? I am using a digitalhall sensor, when connected to D13 the onboard LED is constantly on, and no reaction when a magnet is present. When sensor signal is connected to D2, the LED goes on only when a magnet is present. Definitely not an electronics/ arduino expert, so maybe you can help me and point out what might be wrong?
3 years ago
The is great, it's like an old matrix printer! But I'd warn against using anything other than water on public roads, it could cost you a lot for cleaning and perhaps even a fine.
Reply 3 years ago
Yes, I tested it with water because that reason. But who knows, maybe, someday if I have something important to say it may deserve a little bit of paint.
Reply 2 years ago
There's also spray chalk! You'd need to modify your project to trigger spray cans with solenoids, but it should be doable.
Question 2 years ago
si esta fijo el sensor hall como se puede anular?
Answer 2 years ago
Si la velocidas de las gotas va a ser constante te aconsejo que partas del proyecto que adjunto, te va a ser mas facil modificarlo. La idea es la misma pero con LEDs en lugar de valvulas y sin tener que preocuparse por sincronizar velocidades. Fue el proyecto que utilice yo como partida para la bicicleta.
https://www.instructables.com/Simple-Arduino-POV-W...
Question 2 years ago
hola
Como se puede modificar para convertirlo en impresora de agua vertical, para escribir figuras y letras?
Answer 2 years ago
Muy buenas!
Imagino que te refieres a crear una especie de cascada o cortina de agua de la que vayan cayendo letras o dibujos. Si es así, lo que tendrías que hacer seria modificar el diseño de las letras que están definidas entre las lineas 167 y 617 del código, para girarlas 90 grados. Fíjate en la linea 538, ahí es donde se define el símbolo de admiración '!', ahí se ve bastante bien como están creadas las letras.
Utilizando esa misma lógica podrías crear pequeños iconos, el problema es que tiene muy poca resolución.
Si te fijas en el video de la parte uno, en el minuto 6.44, puedes llegar a ver las letras cayendo al suelo, (mirando desde la izquierda), la primera letra, una T, se ve bastante clara, al resto hay que echarle imaginación, pero lo veo bastante viable tu idea.
3 years ago
This is great! I'd love to see some of the files for the 3D printed connectors you used (or links to them if they're hosted somewhere else). I'd also like to know more about the hall effect sensor, where it's positioned, and how you created a hub on the wheel for it to read.
Reply 3 years ago
Thank you Donald!
I'll upload them to the git hub repository of the project this week. (https://github.com/sagarrabanana/Bikelangelo).
And talking about magnets...
You can see a ring of magnets fixed to the wheel and how the sensor is clipped to the PVC (min 1.27 to 1.30 on the video).
The machine uses them to define the length of each "pixel", this pixel will starts on magnet number 'n' and finishes on 'n+1'. So, if the perimeter of the wheel is 1036mm, like in this case, and the length of the pixel I'm looking for is 75mm, I'll have to distribute 14 magnets around this hub (1036/14=74). The space between magnets must be the same as the dimension of the magnet.
Do I explain myself?
Reply 3 years ago
Wonderful! Thank you.
3 years ago
I 'thought' about making such a device a few years ago BUT didn't do so ! Your post has inspired me to build one ! Do have a source of supply for the electrovalves and the spray nozzles ?
Reply 3 years ago
Hi Mike, I bougth them on Aliexpress, the nozzles are OK (I had a little problem with the sealing of the tank so the pressure wasn't the optimus for the nozzle but it was problem of the tank, not of the nozzle) but the valves aren't very good, they where cheap, but as you can see on the video one of them didn't work properly.
Nozzle: https://bit.ly/3dDl3Cd
Valve: https://bit.ly/2NB5rVt
3 years ago
This is really cool! Awesome build!
3 years ago
Really cool project!
3 years ago
Superb work and it come out excellent........
Reply 3 years ago
There are some issues to tune, but yes! it works fine. Thanks :-)
3 years ago
What a fabulous project! :D