posts tagged with the keyword ‘machines’



I started this project with a goal in mind: test microswitches. Specifically, test the brand of microswitch that I chose for an exhibit I worked on last year. When I was younger, my dad used to have a subscription to Consumer Reports and I remember years ago reading about how they tested things, like using a machine that opened and closed laptops repeatedly to see how many times it could be done before it broke or wore out. One of my goals is to do that sort of thing, but with things we build for exhibits. This is a start. (And yes, I’ve considered just buying/building a robot arm to do these things… I may still do that!)

Meanwhile, since I’m 3D printing again (a lot!) I figured I’d design and print the parts for this machine. Not all the parts… some parts are scrap wood, and (in a recent version) home-made recycled HDPE. The first iteration was a total hack job, and it worked. Sort of. I get in this habit of trying to do press-fit parts, but then I remember that’s a bad idea, so… upgrades happen.


The first version used a PLA plastic arm. Eventually it started to scrape and wear away, and squeak a lot. It was annoying. (Bearings got added to a later version, along with a proper set screw.)


One thing I found out about the cheap microswitches is that the metal arm would bend, and then stop pressing the switch. That’s no good (but good to know.) Then I found times when the switch just wouldn’t trigger the Arduino to advance. Switch failure after just a few tens of thousands of presses? Maybe.


I also had Arduino problems! At some point the cheap eBay Arduino UNO clone from China gave up the ghost and just stopped working reliably. Then I could no longer upload code to it or connect to it at all. Replaced that too!


I also played around with the switch angle… as demonstrated in the above and below photos. I also considered a spring-arm sort of thing the switch could ride on to allow some flex, which would be interesting, but probably less of a real-world test. Maybe.


Here’s a video compilation of some of the testing from early on. This is when I actually thought I could just slap something together and it would work reliably. I’ve since been proven very wrong. I’ll be writing more posts about the changes this machine has gone through and where it stands today. In the meanwhile, if you check out my Instagram or Facebook account, I often post in-progress/sneak-peek photos and short videos.

Stay Tuned!


Click Whir Squee

Occasionally I show up at Milwaukee Makerspace with no clear idea of what might happen when I’m there. This piece, titled “Click Whir Squee” is the result of one such visit. Another member brought in a box of old computer hardware, including a Hewlett Packard Colorado T100E Tape Backup Drive. Being a fan of old technology (1997 is old, right?) I opened up the drive to take a look inside. I also powered it on and stuck a tape in it. The drive came to life and unspooled the tape and made a lot of spinning motor and tape loading sounds. Not everyone knows what these things sound like. It brought back some memories. (At my first job in the tech industry I had to load daily backup tapes into two tape drives. I remember the sound fondly.)

I somehow decided I should mount the tape drive to a piece of wood for display, so I went to the Wood Shop and started cutting up some scrap wood I found. Steve showed up to do some training, so I sat in on that for a bit so I could use the compound miter saw and the band saw. I had all the pieces cut by the end of the evening and knew how I was going to mount it.

I ended up taking all the pieces home and assembling it in my basement workshop. I manage to only split one piece of wood. Just a minor split, but a reminder to slow down when working with wood. The rest of the assembly went very smooth.

Click Whir Squee

Since the majority of fun with this drive is the startup sequence, I decided it should continually turn on, do its thing, then turn off, and keep repeating that. I’ve been playing with ATtiny85 chips lately, so I put one into service to trigger a 5 volt relay (which I also grabbed from Milwaukee Makerspace) and put the following Arduino code on it.

 * TapeDriver.ino

int relayPin = 3;
int onTime = 70000;
int offTime = 15000;

void setup() {
  pinMode(relayPin, OUTPUT);

void loop() {
   digitalWrite(relayPin, LOW);
   digitalWrite(relayPin, HIGH);

Yes, this is pretty much a glorified blink sketch. Sometimes the simplest things are exactly what you need. (Astute readers will see that the device will be on for 70 seconds, and then off for 15 seconds, and repeat indefinitely.)

Click Whir Squee

To power the ATtiny85 and the relay I found a Samsung phone charger on the Hack Rack at Milwaukee Makerspace. It even had a long cord, which was quite useful. You can also see one of the tapes that this machine uses. Now, if you really want to find some contrasts, consider that the modern day phone charger pictured here was used to charge a phone that probably had 8GB (or more) of solid state storage. The tape next to it could store 400MB of data (or 800MB of compressed data.) I should have included a MicroSD card which can store 8GB of data that I routinely buy for about $6 USD.

Click Whir Squee

Click Whir Squee

Since I removed the case there was no indication of what this thing was. I felt I should have something that told a bit of the story. I chose to mount the beige power pack, with “Hewlett Packard” emblazoned on it prominently.

Click Whir Squee

Oh, and while the whir of the motor is quite satisfying, we can do better. There is a wooden arm to which you can affix a small piece of material with a binder clip, which will then be activated when the primary motor spins. Fans of baseball cards and bicycle spokes, this one is for you! I call the “Annoy-o-tron” mode. (Look, if you’re going to use an ATtiny in an Annoy-o-tron, at least be original, right?) I’ve experimented with paper, vinyl, and plastic, but finally settled on a piece from an anti-static bag which some electronics were shipped to me in. It seemed fitting.

Click Whir Squee

Click Whir Squee

Click Whir Squee

Gallery owners and curators take note! This piece is ready to be mounted to a wall, and needs just two outlets to power it. It’s pretty much guaranteed to amuse some visitors while annoying other visitors. Art isn’t always about being pretty.

Enjoy the video below which allows you to experience this wonderful piece over the Internet while in the comfort of your own home (probably while wearing pajamas.)


Here’s a video of the Turndrawble in action… Also, as an added bonus you get to hear the strains of a DC motor moving a gearbox to spin the platter. Turn it up, man!

Don’t forget to check out the blog post and the Turndrawble project page.



If you’ve been following any of my adventures since I first mentioned a Turntable Drawing Machine, this is the result. The Turndrawble is a machine that uses a spinning platter and a movable arm to create drawings.


Unlike many of the things I’ve been working on lately, the Turndrawble leans more towards the “art object” side of things than the “here’s all the files/you can easily make one” side of things. That isn’t meant to say you could not make one, but the prime objective was to create an aesthetically pleasing machine that was unique. (I hope I did that!)

I also wanted to build a machine I could bring to events and allow people to use in order to create drawings. Often in the past I’ve brought drawing machines places but I’ve ether operated them or they’ve operated (semi-) autonomously. The Turndrawble presents a chance for the viewer to become a participant.


(I’ll be posting photos of some of the drawings soon as well. There’s also a video.)

Check out the Turndrawble project page for more info, links to files, etc. if case you want to try to build your own. (I’ve been thinking of building a much smaller and simpler version as a kit you can purchase and assemble. Stay tuned for updates on that.)


One of the pieces I needed for my turntable drawing machine was something to hold a bearing in place underneath the platter to support it and let it spin easily. If you’ve ever taken the plate out of your microwave oven to clean it you may have seen a “Microwave Roller Wheel / Turntable Support” thing. (Really, that’s what it’s called. Check Amazon.)


I decided to use 608 bearings, mainly because I had a lot of them on hand, but they’re also really easy to get for a low price. (I think I got 30 608ZZ bearings for under $20 from Amazon.)

Bearing Mount

I designed these two arms that would fit into slots cut into the base of the machine, below the platter. Each piece would be locked into place with a 3mm bolt, so there’s holes and t-slots for those. The extra piece you see on the bottom (with the 4 slots and 2 holes) is the mating piece. This was designed based on the arm pieces fitting into it, and I would only need to cut one (hopefully) to test the fit.

The arms are slightly different. The one on the right has a hole large enough for the 8mm bolt to fit through, while the one on the left has a slightly smaller hole. The plan was to tap the smaller hole so the bolt could screw right into it without needing a nut. Do a search for metric tap drill size and you’ll see that a 6.8mm hole is needed to tap it for an 8mm bolt. (Sometimes you can just look on the tap and it’ll tell you what size to make the hole.)

As a bonus, when I share the files for this you can decide which pieces suit you better, depending on the availability of an 8mm tap in your workshop. No tap? Just use the larger hole version and a nut instead.

Bearing and Bolt

When you’ve got a laser cutter and lots of scrap acrylic, it makes a lot of sense to make your own washers and spacers and standoffs. (Assuming acrylic is up to the task of what you’re designing.) The spacers were sized to match the inside part of the bearings allowing the outer part of the bearing to spin freely.

I originally was going to make acrylic nuts as well, but decided on tapping the holes with threads. I still wanted the “hex nut” part of the design, as it’s used to hold the platter in place. So that, in conjunction with the tapped parts, prompted me to make the hex shape at the top of the arms. (It’s the details, right?)

Bearing Holder

The one thing that making and using acrylic nuts would have allowed would have been adjusting the height of the bearing. I could have created a slot for raising or lowering the bolt and bearing combo, so with this design featuring the tapped holes, there was no room for adjustment. Luckily I got it right by the second (or third) attempt.

Arm Spacing

Here’s a shot of the spacing of the bearing holders below the platter. It worked out well and I got the math (mostly) right. I may end up making a new bottom in the future to account for other faulty measurements this time around, but I’ve already adjusted for them and things work well enough.

(For other posts about this turntable, check the posts tagged with dcrlmtm.)

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