Here is the Paint Machine. It’s a machine the prints simple bitmaps with spray chalk on the street or sidewalk! Awesome robotic project!
Some of the key features:
- dimension: width: 220cm, length: 38cm, height: 24cm, weight: 12kg
- printing speed: ca. 0.036 km/h
- resolution (4:3): 61px * 46px, print: 225cm * 170cm
- swappable print head
- remote controlled with smartphone app
Here is a list of parts that I used to build it. I’ve probably forgotten some but I think the most important ones are included. Cost for everything is around 600€ but you could definitely save a lot by using used parts or adapt to what you have already laying around.
Motors, wheels and pulleys:
- 4 inline skate wheels with bearings and spacers
- 3 Pololu 50:1 Metal gearmotor
- 4 HTD pulleys, 26 teeth
- 2 HTD pulleys, 14 teeth
- 1 HTD pulley, 18 teeth
- 2 HTD toothed belts, 160 teeth
- HTD toothed belt, 2m
Rails:
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- 5 1m V-slot 2020
- 4 OpenBuilds Solid V Wheel Kits and 2 eccentric spacers
- various OpenBuilds M5 screws, T-nuts and joining strip plates
- 2 micro switches
Main body:
- 18mm birch plywood, laminated, 200cm * 40cm and 80cm * 40cm, called “Siebdruckplatte” in german.
- some wood screws
- wood glue
Electronics:
- Arduino Due
- Arduino Mega Proto board
- 3 Pololu DRV8801 DC motor driver
- 2 Adafruit alphanumeric displays
- Adafruit Huzzah ESP8266
- IRL2203N N-channel MOSFET
- 12V solenoid
- LiPo battery, 11.1V, 3600mAh
For the main board I chose an Arduino Due, that I had laying around for a long time. The Due is a 32-bit controller, running at 84 MHz, so it’s quite fast and it has a lots of pins for IO.
All extensions are soldered on an Arduino Mega Prototyping shield. The three DC motors are powered by a small DC motor driver, the Pololu DRV8801. This driver can handle 8V-36V and up to 1A continuous (2.8A peak). Every motor driver needs a PWM signal to control the speed and one pin to control the direction.
The motors have an encoder attached to its axle. The encoder generates 64 ticks per revolution.
Details and howto guide here: Paint Machine
