BLACKBOARD V-PLOTTER
Introduction: BLACKBOARD V-PLOTTER
In this instructable, I'd like to share how to build a vertical plotter that can draw texts and images on the blackboard.
Let's getting started.
Time-lapse video with hatch fill extension from Inkscape.
Step 1: Bill of Materials
Main components:
* 1pcs x Arduino Mega 2560.
* 1pcs x RAMPS 1.4 Controller.
* 2pcs x A4988 Stepper Driver Module.
* 2pcs x Stepper Motor NEMA 17.
* 1pcs x Servo Motor SG90.
* 1pcs x Blackboard Dimension 780x1200mm.
* 1pcs x GT2 6mm Timing Belt 2000mm.
* 2pcs x GT2 Timing Pulley 80 Teeth.
* 2pcs x XH2.54mm – 4P 20cm Wire Cable Double Connector.
* 2 meter x 8P Rainbow Ribbon Cable.
* 2 meter x Two cores Power Cable.
* 1 meter x PVC Square Plastic Electrical Conduit.
* 1pcs x Empty Plastic Coil Spool. I reuse empty plastic coils that is used to coil the soldering tin wires.
* 2pcs x Cable Gland For 8 - 12mm Cable Diameter.
* 16pcs x Round Neodymium Magnets 10mm x 2mm.
* 1pcs x Power Supply 12/24 VDC.
* 1pcs x Arduino programming cable with length 1.8m.
* Some nut M10, cable ties, paper A1 size.
Step 2: Ideas
Blackboard V-Plotter is a kind of CNC plotter that draws texts and pictures by moving a pen on a vertical surface. It has a simple mechanical structure, including:
* One blackboard.
* Two stepper motors with pulleys and belts.
* One pen lifting micro servo.
* Couple of counterweights.
* And gravity force.
I have an 780 x 1200mm blackboard that my kids no longer use, so I make use of it to build a vertical plotter. My vertical plotter configuration is described in the picture below.
* Machine Width: 550mm.
* Machine Height: 800mm.
* Belt Length: 1000mm.
Step 3: Blackboard Assembly
* Preparing a blackboard, my blackboard has outer dimension 780 x 1200 mm including aluminum support width 30mm.
* Drilling 2 holes for mounting 2 stepper motors, the distance between two hole centers is 600mm.
* Mounting 2 stepper motors at the backside of blackboard.
* Attaching 2 pcs x pulleys 80 teeth to the motor shafts at the blackboard frontside. Pulley GT2 80 teeth has a pitch of 2mm per tooth so its diameter is: 80x2/PI = 50.955mm.
* Drilling 4 holes to mount Arduino Mega 2560 + RAMPS 1.4 board at the blackboard top center.
Step 4: Pen Holder Assembly
The main components to build the pen holder are including as follow:
* Flow coupler, including dust cap.
* Empty tin wire plastic coil with center hole diameter 19mm, height 23mm and outer diameter 55mm.
* GT2 6mm timing belt 2000mm and two cable gland for 8 - 12mm dia. cable. 1000
I used 2 type of cable glands, one is made from plastic, the other from metal.
Firstly, I cut 2m timing belt into two segments, each 1m length. To hang the pen holder, I removed the chains from flow coupling and connected them to 2 timing belts by cable ties.
Two cable glands were inserted into center hole of empty plastic coil. I drilled 8 holes and installed 4 bolts M3x50 symmetrically along the plastic coil to hang the timing belts. Later we can use these bolts to hang additional counterweights if needed.
I glued a servo at bottom of plastic coil (at metal cable gland side) and soldered 3 wires from servo to RAMPS 1.4 controller. Finally, pen holder was hung on the motor stepper pulleys. I moved it manually and checked if it slipped or not.
Update: The pen holder was shaked and vibrated during plotting so I had to did some adjustments to get its balancing. The steps are as follows:
* Adding some more counterweights - nuts M10.
* Connecting the tin wire plastic coil with a round plastic, 100mm in diameter, thickness 10mm.
* Glueing the micro servo into round plastic and adjusting the servo arm so that it is as close to the pen tip as possible. 582