Gondola PlottyBot v2 – Ben's blog
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Table of Contents
Introduction
This is Gondola PlottyBot v2 , a vertical pen plotter you can build.
It’s based on a Raspberry Pi Zero 2 W and comes loaded with software to make it easy to use. It’ll create its own wifi network to connect to, but you can also have it connect to an existing one. Then controlling it is web based.
Deployment size is arbitrary, you can make a small one or a really big one.
Downloads
STL Parts for 3D Printing
Raspberry Pi SD card image
Circuit Diagram (optional: for reference)
Parts to Gather
3D Printed
All parts available here: download link.
weight_cap_x3.stl<br>side_weight_x2.stl<br>gondola_weigth_x1.stl<br>belt_looper_x4.stl<br>gondola_x1.stl<br>logic_box_cover_x1.stl<br>logic_box_x1.stl<br>motor_holder_x2.stl
Each file name contains the amount to print at the end (x4 means print 4 of this part).
Acquired
Tools to have
soldering iron<br>glue gun (or sugru moldable glue)<br>allen wrench set<br>small phillips screwdriver<br>needle nose pliers<br>voltmeter (preferable)<br>cordless drill (preferable)<br>xacto knife<br>wire snippers
Circuit
Here is the circuit diagram for reference. It is not needed for the instruction point out what to connect where, it’s only useful to cross-reference information.
Build Instructions
Logic Box
This is the meat of the project.
Perma Proto Bonnet Headers
Parts
Perma Proto Bonnet Mini Kit x1
First we’ll solder the headers the Perma Proto Bonnet came with. In years of building drawing machines, the Bonnet approach seems to be the best mix for building a stable machine while keeping some flexibility in building.
You an use tape to hold the header in place and solder a couple of pins to hold it instead of the tape.
Power to the Pi
Parts
12V power supply x1<br>12V power connector (female) x1<br>5V voltage regulator x1
Grab the 5V voltage regulator
We will hard set it to give us 5V, to do so we cut the potentiometer out, and we solder the 5V option.
Then we solder the female 12V power connector.
Plug it into the 12V power supply, make sure you have 12V at the supply side, and 5V at the orange wire.
Perfect, now let’s solder it into the Perma Proto Bonnet !! make sure the power supply is unplugged first !!
First Pi Boot
Parts
Raspberry Pi 2 Zero W x1<br>SD Card x1
With the power supply still unplugged, attach the bonnet to the Pi.
Download the Gondola PlottyBot Pi image, and write it to the SD card using the Rapsberry Pi Imager. When you get to the "OS" section, scroll all the way to the bottom to "Use custom" and point to the img file you just downloaded.
Stick the SD card in the Pi, plug in the power supply and you should see the Pi’s LED light up.
Now this first boot will take a good 10 to 15 minutes. It’s a good idea to not get impatient a unplug it. The first time things start, a whole lot of packages are being installed on a Pi Zero which is not exactly the spiffiest machine out there :). Rest assured it’ll have more than enough horsepower to run the plotter once everything is installed. You will know it’s done installing when a new wifi network shows up.
Go ahead and connect to it. Once connected, point your browser to http://plottybot.local (or http://10.0.0.5 if this didn’t work). You should see Gondola PlottyBot’s web interface:
Super! No need to do anything in there we just wanted to make sure it worked. Let’s unplug the power supply, we’ll keep working on our circuit.
Stepper Motor Drivers
Parts
stepper driver x2
The stepper drivers have 2 pins which aren’t useful and will get in the way of circuitry so we snip them out.
Do so for the both of them. Then position them on the proto bonnet, and solder their pins on the bottom side.
Whenever we solder something on the bottom side, we snip out extraneous tails.
Watch your proto bonnet, it has a 5V bus and a 3V bus. They are separated even though they follow the same line, you want to make sure you tap into the right bus when you bring voltage somewhere. The ground bus is running continuously parallel to them.
We bring 3V to them to their MS1 pin.
When we solder it, on the other side we bridge the MS1 pin with the MS2 pin so they will both get 3V .
The documentation for these stepper drivers says that pulling both MS1 and MS2 up activates the highest microstepping.
We also bring 3V to their VIO pin. This is to power them.
They need 2 grounds each, so we bring 4 wires from the GND bus to their GND pins.
We bring Pi header pins #4 & #5 to the stepper drivers’ DIR (direction) pins.
Then we bring Pi header pins #17 & #6 to the stepper drivers’ STEP pins.
Then we bring Pi header pins #24 & #16 to the stepper drivers’ EN (enable) pins.
Finally we add 2 wires to our female 12v connector and solder that into each driver’s VS (Volt Supply?) pin. This power is for the motors. The stepper drivers need only 3v to run their logic which they get from the Pi, but the stepper motors need an independent 12v.
Space is getting tighter, and we’re about to make...