LY Drawbot, a $70 pen plotter
Updated: Nov 8, 2020
Pen plotters can get pretty expensive. The Axidraw, one of the most popular pen plotters used in the generative art community, will set you back by $450. Although its precision and reliability are excellent, some newcomers to the genre might want to explore other options.
I decided to test a pen plotter on the opposite end to the spectrum.
Meet the LY Drawbot, a pen plotter DIY kit available on Aliexpress for $70.
Highlights of LY Drawbot
- A4 drawing area
- Comes as a Kit (non-assembled)
- G-Code based, controlled via UGS (Mac, Windows or Linux)
- Cheapest A4 plotter I could find
Aliexpress announced a lead time of 2 months or they'd refund me. The LY Drawbot took 5 weeks from order to shipping and another 2 weeks in transit, so close to 2 months of wait in total, but in line with their policy, I guess.
The LY Drawbot comes as a kit, which you'll have to assemble. There is no printed manual, but the seller sent me a link with the instructions, software, and examples so I didn't have to improvise during the build. Here is the manual if you don't get it directly from the seller.
The LY Drawbot runs on an Arduino Uno, with 2 stepper motors driven by Pololu A4988 drivers, similar to many budget CNC and 3D printers. It comes with a 12V/2A power supply (US format, with an EU adaptor). The structure is made of aluminum extrusions and most parts are either laser cut acrylic or 3d printed. The extrusions were a little greasy so I gave them a cleanup before starting assembly.
The linear bearings are very low tech, but when you're budget you've got to be clever. The cable tie arrangement is providing just enough wiggle for the motion to be smooth.
The central block is easy enough to put together, although there are two sizes of linear bearings. You'll soon realise if you haven't got it right.
The next step is to set the stepper motors up and install the central block on the rods. The two end blocks of the Y-axis are 3d printed, and during the tensioning of the belt, I wondered how much tension they would handle, but I didn't have any issue. The belt rests on small bearings in the end blocks, so once set up there's not much friction.
The Arduino (definitely not genuine) sits on one of the motor blocks. Cables to the steppers are routed through the aluminum extrusion. This is the only part I had to undo a couple of times to get it right, because once the Arduino is mounted, some of the screw sockets aren't accessible anymore, preventing further adjustments. The design features a small fan, which means the drivers will probably get quite hot during long prints. As a result, the plotter is emitting a constant humming noise.
It's finally time to assemble the pen holder block, with the servo motor at its back. The pen holder itself is bend sheet metal, pretty similar to the Axidraw one, so you can expect to fit a wide range of pens in there. The block is "spring-loaded" with an elastic band that will accentuate the pressure of the pen beyond mere gravity. The pressure is quite high with the default elastic band in my opinion.
Overall the design of this affordable plotter feels sturdy enough to do the job, although I'd expect more maintenance than on an Axidraw. So far the only mods I've done were to add a couple of adhesive rubber feet under the motor blocks to prevent it from sliding from the table.
Unlike other plotters, the LY Drawbot can't be run directly from within Inkscape or other vector editing software. I assume the Arduino is loaded with what must be a version of Marlin or something like this, that can interpret G-Code. This means your workflow will have to include both creating G-Code from your generative artwork, and then feeding it to the LY Drawbot.
Before jumping into plotting, you'll have to install CH340 drivers for communication with the Arduino over USB. Here are the files I got provided by the seller.
Then you need to grab the latest version of Universal Gcode Sender (UGS) for your OS and connect with the plotter. You should be able to move your plotter around with the arrows on the GUI. You can input commands in the text box to test things are working properly. M5 sends the pen up, M3 S1000 sends it down. It seems these commands are a classic trick for pen plotters to use the same type of g-code to run a laser cutter.
I did not review other G Code software but I'm sure they'll work just as well.
Time to feed our cheap plotter some code! Here's how to. I've been using the J Tech Laser Engraving plugin for Inkscape to generate my G-Code. Open your vector artwork and head to the extensions to find the J Tech plugin. From there, you'll export your G-Code to a file on your computer. Have a look below for my parameters.
From there, load up your G-Code on GCS, connect to your drawing machine and hit the button.
Let's have a look at this pen plotter in action. As you can see, the behavior is quite good. The motion is smooth enough and the position accurate. I'm using a very robust fine liner here, but I expect most pens will do a decent job.
Unlike an Axidraw, you can't tune the type of speed and acceleration you want for your strokes so you're a bit more at the mercy of the raw G-Code but for most simple plots that should be fine.
What I like
Overall I'm quite impressed by how decent this plotter is. I was expecting to struggle a lot more on the assembly given the price point. The precision is quite good.
There's probably a bit more calibration for me to do to use it for generative art prints I'd sell but I feel it's 90% there. I expect I'll need to spend some time on maintenance and calibration after some mileage. This is not the type of plotter you'd want for a plug and play experience but it's actually quite nice to have built it and understand its principle a bit more in-depth. All in all, this feels like the type of gear I'd have love to get started on pen plotter art.
What I wish
Better software would be nice. I find it quite tedious to jump from one program to another when I know I could do it all in Inkscape with my Axidraw. The level of control over the code is also very minimal. Path order feels quite random. I also find the speed of pen up and pen down quite hard to set.
As mentioned before, the aluminum extrusions didn't feel very clean, and the acrylic used for the laser cut parts also felt quite low quality, but again, for this such a cheap pen plotter, it's expected.
To sum up this review, the LY Drawbot is definitely a good fit if you're a maker on a budget. Newcomers to generative art can definitely expect hours of fun plotting their designs before they feel ready to jump on a more premium piece of equipment. Its pen holder will allow you to experiment with many different kinds of pens and bring your creative coding to the physical world.
If you don't like tinkering or feel uncomfortable with a non-calibrated machine, this is probably a pass. On the other hand, the makers will definitely enjoy building their plotter and understanding its inner workings.
The drawing area (A4) is plenty to start with. I personally own an A3 Axidraw, so I felt a bit squeezed at first in comparison, but this really depends on what you want to do with your plots.
Where to buy
You can get the LY Drawbot on Aliexpress for $66.90