Drawbot ✏️🤖

Drawing robot capable of rendering SVG paths over WebSockets. Powered by a Raspberry Pi running Node.js.

Parts List

Printable Parts

• Motor Mounts (two of each)
• Electronics Case
• Pen Holder Gondola
• Servo Horn Extension

Everything Else (~$150 or less)

• NEMA 17 Stepper Motors, 36.8oz.in 12v 0.4a (need 2) - $23.98
• Suction Cup with Quick Release (x2) - $5.98
• Spiderwire 80-pound fishing line - $17.56
• Micro USB cable 10-ft. 2-pack - $8.99
• Micro USB breakout 10-pcs (only need 2) - $6.59
• USB type a female breakout 2-pack - $4.50
• Raspberry Pi Zero W - $10)
• Easydriver Stepper Motor Driver (2-pack) - $9.99
• SG92R Micro Servo motor - $6.99
• 6003zz bearing 17x35x10 (need 2) - $11
• 10pcs 500mm 3-pin servo extensions (need several) - $7.69
• 2.1mm x 5.5mm barrel jack 15pcs (need 1) - $7.59
• 12v 1a power adapter 2.1mm/5.5mm lead - $9.99
• USB Micro Power Adapter - $5.99
• Pololu Universal Mounting Hub for 5mm shaft, #4-40 holes (2-pack) - $11.44
• USB fan (40mm) - $7.99
• #8-32 x 1-5/8 in. Eye Bolts (2-pack) - $0.98
• 8 screws for spools (#4-40 x ~½")
• 8 screws for motors (M3-.50 x 6mm metric machine screws)
• 1-2 small screws for gondola to secure pen/marker
• Mounting Putty - $4.87
• Standard wire or jumper wires (and headers for components if using jumpers)
• Dry erase markers (or other drawing implements)
• Micro SD card (class 10 or better)

Wiring

Hardware Assembly

Thank you to the kind people at the Johnson County Library's Black & Veatch MakerSpace for documenting the assembly process at instructables.com.

Raspberry Pi Zero W Basic Setup

1. Download and install Etcher.
2. Download and install latest Raspbian OS and flash it onto your SD card with Etcher.
3. Enable SSH by adding a blank file named ssh (no extension) to the boot directory on the Pi's SD card. (Last tested with Raspbian Stretch Lite 2018-06-27 version.)
4. Set up Wifi by adding a file named wpa_supplicant.conf to the same boot directory with the following contents (replace MySSID and MyPassword with your credentials):

   ctrl_interface=DIR=/var/run/wpa_supplicant GROUP=netdev
   update_config=1
   	
   network={ 
   	ssid="MySSID" 
   	psk="MyPassword" 
   }
   

Software Prerequisites

From a device connected to the same network as the Drawbot Pi, SSH into the Pi with ssh pi@raspberrypi.local. The default password is raspberry.

Then, on the Drawbot Pi:

1. Update, upgrade, and install NPM, Git. (Automatically answer "yes" to everything.):

   • sudo apt-get update
   • sudo apt-get upgrade
   • sudo apt-get install npm
   • sudo apt-get install git

2. Install Node.js.

   • sudo npm install -g n (Install n for node.js version management. github.com/tj/n)
   • sudo n stable (Install latest stable version of Node.js. Last tested with v10.8.0)

3. Upgrade NPM. (and remove old apt-get version).

   • sudo npm install npm@latest -g
   • sudo apt-get remove npm
   • sudo reboot (After rebooting, you'll have to SSH into the Pi again.)

4. Install pigpio C library. npmjs.com/package/pigpio

   • sudo apt-get install pigpio (Only if you're using Raspbian Lite.)
   • npm install pigpio

Installation

On the Drawbot Pi:

1. git clone https://github.com/andywise/drawbot.git to clone this repository.
2. cd drawbot
3. npm i

Use

On the Drawbot Pi:

• Run npm start or sudo node draw.js to start the Drawbot controller.

Controlling the Drawbot

On a device connected to the same local network as the Drawbot Pi:

• Go to raspberrypi.local/control to access the Drawbot control interface.
• Use the "bullseye" interface to manually position the gondola, or raise/lower the pen/marker.
• Use the settings panel to configure the Drawbot's D, X, and Y values (see "Configuration" below).
• Drag and drop an SVG file onto the control interface to send artwork to the Drawbot!

SVG Artwork Notes:

• Only the first <path> element will be drawn, so if necessary, combine artwork into a single compound path.
• The Drawbot will scale artwork so that 1 pixel = 1 millimeter.

Configuration

• Enter value for D: measure distance between string starting points (in millimeters).
• Enter starting X and Y values: measure distance from left and top (respectively) of left string starting point to initial pen position (also in mm).
• Note: Values will be stored in the config.json file.

Rendering Raster Artwork (Coming Soon!)

• For now, go check out "TSP Art."