Small drawbot pen holder installed.

I managed to get the new gondola design installed on the baby sized drawbot.

I already see a lot of problems. For instance I could mount the pen at the top of the gondola instead of the bottom. And have the ballast towards the problem. Also the elastic attachment point could be better.

Either way this looks fully functional and is coming to a pub near you. 🙂

12V Power Supply

As some of you may know the DrewBot that was ready for shipping went missing! I’ve alerted the police and 5 radio stations in case that can make a difference (unlikely by the looks of it). I will keep an eye on that.

I’ve got another machine ready to go but I didn’t have a power supply.

I found one among my junk that’s barely adequate.

I’m just running a stress test on it right now while I box up some Squirrels.

DrewBot installation

Here is how to install the DrewBot.

1) Mount spools.

2) String up gondola (see video).

3) Place controller.

4) Run wires from controller to spools.

5) Connect power to spools.

6) Connect controller to USB of computer. Let driver install.

7) Start software.


Nuts for layered fabrication

The Mr. Drew pen holder/gondola uses some circle-nuts with 1/4-20 threaded rod. That works very well since you can disassemble and reconfigure the stacks of parts.

On the down side, if you ever try and hold an acrylic nut in your hand and thread it you will see how much force it takes. I threaded about 30 of them and my hands were pretty tired.

So I decided to go with oval nuts and see how that works out.

I made a jig for threading them. I’ll report back on how good this works. I should be assembling a few gondolas over the next few days (and other parts using this fastening technique).

Unpacking Mr. Draw and assembling Gondola

I use foam, plastic and newspaper for packing so unpack carefully from the top of the box (the address label is on the front side). So you face the label towards you and the top of the box will be upward.

Once you have everything out of the box, the gondola (pen holder) may need some assembly.

The gondola ma be divided into two parts. You’ll want to carefully remove the two wooden disk nuts that are screwed on the pen holder and screw the assembly onto the base. Be careful not to loose all the parts off the threaded rod.

Once you screw the two rods into the base, then tighten the red circle nuts by hand (be careful not to strip). Just use enough force so it wont come apart. Make sure the threaded rod isn’t screwed through the base since it will contact the drawing surface (no big deal but it might scratch).

Mr. Draw Walkthrough

This is the latest drawbot I made. It’s mostly acrylic and a bit of hardboard.

I think I’m finally on to something with the new gondola (pen holder).

New Gondola for Drawbot

I spent about 10h in the lab making a new gondola, electrical cabinet and new spool holders for the drawbot.

I compressed it into a 2m video for fun.

I had to make a few metal parts as well by cutting off some 1/4-20 rod.

I did some redesign of the gondola so it has the following improvements.

-It is now bolt together and is very configurable.

-You can vary the point of attachment of the cables.

-There are now three positions for ballasts. A new one at the bottom to increase stability.

-It is now transparent.

-The clamp is cut away so you can see the pen.

-The area where the pen contacts the paper is cut away so the observer can see the pen contact.

The new spool holders are in red translucent acrylic. I also made a cover for the electronics.

Big Bot drawing test

This is working quite nicely. I made some mistakes on the conversion of colors to shades but I’m going to let it run through to see if there are any other issues.

What happens when the pen runs out?

I’ve been asked this question many times.

I usually tell people that the machine bursts into flames.

Here it is on film.

New pen holder for drawing robot

My clamping gondola didn’t work very well so I made another attempt. This time I added a clothespin type lever so you can easily remove and add pens.

I need to add a ballast as it’s off balance. I guess I could move the point of attachment of the string closer to the wall.

I’m betting this one will be very stable.

Larger format drawing robot

Okay, I did a run with the new configuration. The new gondola doesn’t work very well and as you can see in the video I was making another one while this sketch was being made.

I added some clamps for weight. They interacted with the table but I got away with it.

The picture still came out okay.