This week on Maker Update, a self-driving garbage can, flat-pack furniture, multimaterial goes lenticular, a Slack dial, animated origami, cassette sound sculpture and nailing the mil-spec look.

++Show Notes [Maker Update #196]++

-=Project of the Week=-

Self-driving trash can controlled by Raspberry Pi by Ahad Cove
https://www.raspberrypi.org/blog/self-driving-trash-can-controlled-by-raspberry-pi/

-=News=-

Ben Uyeda, A05 Studio Team Up for Tool-Free Flatpack Furniture
https://www.core77.com/posts/101502/Ben-Uyeda-A05-Studio-Team-Up-to-Launch-Sustainable-Tool-Free-Flatpack-Furniture-Brand

Lenticular Effects on 3D Objects
https://www.core77.com/posts/101458/Design-Duo-Spots-Untapped-Potential-of-Multimaterial-3D-Printing-Lenticular-Effects-on-3D-Objects

-=More Projects=-

Slack Status Updater With ESP8266 By bekathwia
https://www.instructables.com/id/Slack-Status-Updater-With-ESP8266/

Mollusca by Jiani Zeng
https://vimeo.com/403116454

Folding 3D printed mechanisms by Federico Tobon
https://www.patreon.com/posts/41003741
https://www.prusaprinters.org/prints/39707-folding-mechanism-3d-printed-on-fabric

Back7.co Mil-Plastic Cyberdeck
https://back7.co/home/back7co-mil-plastic
https://www.thingiverse.com/thing:4579460

MCP – Cassette player by Love Hulten
https://www.lovehulten.com/mcp.html

-=Tips & Tools=-

Variable power for your projects
https://hackspace.raspberrypi.org/articles/variable-power-for-your-projects

Big Idea Design Titanium Pocket Bit review by Matt Stultz
https://kk.org/cooltools/edc-titanium-screwdriver/

Gareth’s Tips, Tools, and Shop Tales – Issue #59
https://www.getrevue.co/profile/garethbranwyn/issues/gareth-s-tips-tools-and-shop-tales-issue-59-270825

Folding paint rack for 25mm bottles by Feday
https://www.prusaprinters.org/prints/32348-folding-paint-rack-for-25mm-bottles

-=Digi-Key Spotlight=-

How to Safely Discharge a Capacitor
https://youtu.be/aEupCE9btEU

Transcript

This week on Maker Update, a self-driving garbage can, flat-pack furniture, multimaterial goes lenticular, a Slack dial, animated origami, cassette sound sculpture and nailing the mil-spec look.

Hey, I’m Donald Bell, and welcome back to another Maker Update, the show where I update you on what makers are up to. I hope you’re doing well. I know I always talk up each week’s show, but seriously, this one is really something special and a little longer than usual. It’s weeks like this that remind me why I love making this show. So let’s get into it, starting with the project of the week.

Ahad Cove made this self-driving garbage can that automatically drives itself out to the curb on garbage day. 

It’s one of those ideas that sounds deceptively simple, but to truly make everything automatic you have to solve a lot of problems along the way. 

To motorize the trash can, Ahad’s using a brushless hub wheel motor and an inexpensive driver board, all connected up to a Raspberry Pi computer and a rechargeable battery pack. All of this gets installed inside the bottom of the trash can. 

But that’s the relatively easy part. To deliver the garbage to the curb just in time, he needed a way to detect when the garbage truck was approaching, and then signal his garage door to open and then signal the bin to move out to the curb.

To solve this problem he trained a machine learning algorithm to detect garbage trucks from a webcam mounted in an upstairs window. This system uses an NVIDIA Jetson Xavier board so that the detection can happen as quickly as possible.

After detecting the truck, it signals the Wi-Fi compatible garage door to open, waits the required amount of time, then signals the Pi in the trash bin to run the motor for the length of the driveway, and then activate a high-torque servo that pulls the motor brake.

It’s complicated, but when he gets it to work, it’s a great feeling. I don’t think I hate taking out the trash enough to go to this length to automate things, but I love knowing that it’s possible and I get such a thrill seeing the engineering challenges get solved.

Now for some news. Designer Ben Uyeda of HomeMade Modern is teaming up with A05 Studio to release a new sustainable furniture brand called Hoek Home. What they’ve been teasing so far is a line of tool-free, flat pack furniture. In a series of instagram videos you can see how the HDPE plastic legs ship in fitted pockets that are built into the underside of the table. All you have to do is pull them out and snap them into place. By squeezing the leg, you can also remove it and store it back in its little cutout.

It’s apparently a patented system, but I think it’s an awesome idea to put to your own personal use, especially if you have a CNC router.

Another technique I’m dying to explore is this lenticular 3D printing effect shown here in the work of Jiani Zeng and Honghao Deng. This work recently won a Core77 Design Award in Strategy & Research.

When you think of a lenticular effect, it’s usually something to do with creating 3D or animated images. The idea is essentially that clear, raised lines, with a particular shape, can bend light to a degree that the image or color beneath it and be revealed or obscured depending on the angle you view it.

To pull this off as a 3D printing technique, you apparently need to make use of multi-material printing technology, though there’s also an example in this video reel of 3D printed lollipop candy molds, which in my mind could be done with traditional 3D printing.

Either way, it’s an exciting technique to think about, and the effect opens up some cool design possibilities.

Now for more projects! Becky Stern teamed up with Brian Lough (lock) to create this physical status updater for Slack. Now, if you’re away from your desk, or eating lunch, or walking the dog, you can just set the dial without having to go into the software.

The project uses a rotary switch and a NodeMCU board so that it can connect to wi-fi. The rest of it comes down to just a 3D printed enclosure and printing up a little label for different states you define in the code. 

Because of this project there’s a new Slack API library for Arduino now. So if you have other Slack-related project ideas, this could open those up. You can find the full guide on Instructables.

While reading up on the lenticular 3D printing technique I stumbled across this other project that Jiani Zeng collaborated in. This is a crawling robot called Mollusca. It’s body is made from a sandwich of two sheets of vellum paper and a layer of double tack adhesive film. 

The whole thing is then laser etched with an origami-inspired folding pattern and then folded into shape. Two servos along the spine act as pulleys that create a kind of pulsing motion that drives it around. 

For similar idea at a smaller, more approachable scale, check out this experiment from Federicon Tobon. 

Inspired by some of the 3D printed origami experiments I made last November, this is a 3D printed pattern printed to polyester fabric. Noticing that the shifting design had some mechanical properties, Federico designed-in a slot for a paper clip crank and turned it into a kindo of origami automata. 

You can find his build diary on Patreon and the 3D printed design on Prusa. 

For another project with that “I can’t believe it’s 3D printed” vibe, check out this military-inspired Raspberry Pi cyberdeck by Jay Doscher at Back7. 

Jay’s done a bunch of awesome Pi field kit designs worth checking out, but this is a whole new approach he’s showing here. 

First, there’s the military green PETG filament he found, which just looks perfect for a project like this. 

He’s also using threaded brass, heat-set inserts to connect a lot of these parts together. Not only does this allow you to repair and modify things later on, but it gives the face of it a cool, riveted look. 

It also allows you to put a textured build plate finish on more pieces, because you can print them separately and attach them later. So much of this looks injection molded because you’re seeing build plate texture on everything.

Finally, notice how he creates these fins on the pack using separately printed sections that he binds together with threaded rod. Not only does this give it some metal reinforcement, but again, it allows him to take advantage of build plate texture, at least on one side of each fin. 

I also just have to mention that Jay designed all of this, and all of his other amazing designs, using Tinkercad. So for all you CAD snobs out there who say you can’t make complex designs in Tinkercad, I’m telling you, the only limits are imagination and ingenuity.

Designer Love Hulten has plenty of both. His latest project, offered without explanation is this pitch-controlled cassette player he calls the MCP. 

The top dial controls both the playback speed (and thereby the pitch) of the cassette player, as well as the rotation speed of the wind-up key-looking thing next to it. This might actually be a Leslie organ style rotating speaker, but I can’t be sure just from the video. 

The box next to that just appears to be a box of blinky lights, and I have to presume the other dial on the cassette deck is volume. 

Who knows why this crazy thing came into existence, but do I want to play with it? Absolutely. And like all of Love’s work, I’m in awe at the level of thought that goes into the finishes and details. The dreamy, retro color scheme. The custom, coiled audio cable. It’s a work of art.

Now for some tips and tools. On Hackspace, there’s a great article on the types of inexpensive DC to DC variable power supply boards you can get your hands on and how to use them. 

These come in handy when you have a few different elements in a project that have different voltage needs. I’ve used them on Pi robotics projects where I have 12 volts coming in to power motors, but I need 5.1 volts to keep my Raspberry Pi happy.

On some basic models you can dial in the voltage using a tiny built-in potentiometer and reading the result with a multimeter. For a few dollars more, you can find these with a built-in voltage display, or a separate trimpot for dialing in the amperage. 

On the Cool Tools channel, I’ve got another interview up with Matt Stultz talking about the Big Idea Design Titanium Pocket Bit. This is a two sided bit that fits right onto your key ring. It’s super minimal, but super strong because it’s made from titanium. Check out the video for more information.

In the latest issue of Gareth Branwyn’s tips, tools, and show tackles newsletter, reader David L. sent in a great tip on storing and sorting sheets of sandpaper in a portfolio style accordion file. I’m totally doing this one.

And from the Adafruit blog I found this folding model paint rack from Feday. This holds 25mm bottles of paint, and it can fold down flat or prop up at an angle with a little geared leg. I thought it was neat.

Finally, for this week’s Digi-Key Spotlight, check out this video on how to safely discharge a capacitor. 

This is especially useful when you’re working on equipment with large capacitors that can store a deadly amount of charge.

In this video you’ll learn how to measure the stored voltage on a capacitor, and how to select the right resistor value to safely bleed off the excess voltage. 

As an alternative, you’ll also learn how to drain a capacitor using an incandescent bulb with a voltage rating higher than the capacitor. That was a new one for me.

Alright, and that does it for this week’s show. Am I crazy, or were the projects this week awesome. Let me know what your favorite project was down in the comments. Also, be sure to subscribe, and leave me a thumbs up. You can get on the email list so that you never miss a quality episode like this one again. Big thanks to my Patrons on Patreon and an extra big social distance high five to Digi-Key electronics for making this show possible. Thanks for watching, and I’ll see you next week.