Building A Hydraulic Lego Excavator Using Standard Pneumatic Cylinders

August 21, 2023 by 12 Comments

Everyone already knows that Lego Technic is pretty rad when it comes to existing, pre-made kits, but there’s also quite a bit of hacking potential left. One such area is the lack of hydraulics in Lego Technic, an egregious oversight that [Brick Technology] simply had to correct. His effort results in a partially hydraulic, fully remote-controlled excavator. Rather than a traditional gear hydraulic pump as you’d expect in a real-life excavator, a custom peristaltic pump is used to move the fluid to the hydraulic cylinders (rams for our British and Oceanic friends).

The undercarriage is (sadly) purely electrical, with a slip-ring providing power to the electric final drives in the tracks, enabling it to spin around endlessly without limitations. Where the hydraulics come into play is in the excavator’s arm, with two hydraulic lift cylinders on the boom, one cylinder to control the stick, and a final cylinder to control the bucket. Rather than a hydraulic switch, the setup is simplified by using a single peristaltic pump per cylinder circuit.

Remote control and power are provided using the rather chonky BuWizz 3.0 Pro, which offers a wireless control link (here controlled using BrickController 2 on Android). Although original Lego cylinders were used, these are only intended for pneumatics, where it’s hoped that the used mixture of water and windscreen wiper fluid will prevent corrosion.

(Thanks to [Keith Olson] for the tip)

Continue reading “Building A Hydraulic Lego Excavator Using Standard Pneumatic Cylinders” →

A picture of the JagerMachine consisting of rectangular, desktop sized drink serving machine with a wooden varnish, a 3.5 inch touchscreen on the front face on top and a cavity with a shot glass in it, lit up by blue leds, with liquid pouring into it.

Shoot An Email To Get A Shot

October 17, 2022 by 4 Comments

[_Pegor] wanted to create a shot pouring machine for their friends birthday. Unfortunately, the build wasn’t done in time, but at least the JagerMachine is finished now so that others can use it.

The JagerMachine has a peristaltic pump that moves liquid from a reservoir hidden in the back of the machine to the glass in front. The machine has a 3.5 inch DSI touch screen display for user input and a WS2812B LED ring for creating a small light show when the drinks are served. A 3.3 V to 5 V level shifter is used to power the LED ring and a motor driver module is used to drive the peristaltic pump motor. It looks like there’s a “shot glass detection” feature that uses a 3D printed mini platform with a notch for a magnet so that when a glass is placed on top of it, the hall sensor can detect the presence of the nearby magnet.

Part of the charm of this project is the software stack on the Raspberry Pi that allows for novel interaction, including being able to serve drinks from the receipt of emails. Using the Raspberry Pi as the controlling device allows for this rich set of interfacing options, including easily allowing the ability to drive the LEDs, detect the presence of the shot glass, along with establishing network connectivity. The setup procedures are all documented in the repository for anyone wanting to see how this type of functionality might transfer to their own project.

Drink mixing robots are, of course, a thing. ranging from small and cute to full shelf.

Extruded Resin FDM Printing (With Lasers!)

June 22, 2022 by 24 Comments

At this point, 3D printers are nearly everywhere. Schools, hackerspaces, home workshops, you name it. Most of these machines are of the extruded-filament variety, better known as FDM or Fused Deposition Modelling. Over the last few years, cheap LCD printers have brought resin printing to many shops as well. LCD printers, like their DLP and SLA counterparts, use ultraviolet light to cure liquid resin. These machines are often praised for the super-high detail they can achieve, but are realllly slow. And messy —  liquid resin gets everywhere and sticks to everything.

We’re not exactly sure what [Jón Schone] of Proper Printing was thinking when he set out to convert a classic printer to use resin instead of filament, but it had to be something along the lines of “Can you make FDM printing just as messy as LCD printing?”

It turns out you can. His extremely well-documented research is shown in the video below, and logs his design process, from initial idea to almost-kinda-working prototype. As you may expect, extruding a high-viscosity liquid at a controlled rate and laser-curing it is not an easy task, but [Jón] made a fantastic attempt. From designing and building his own peristaltic pump, to sending a UV laser through fiber-optic cables, he explored a ton of different approaches to making the printer work. While he may not have been 100% successful, the video is a great reminder that not all projects have to go the way we hope they will.

Even so, he’s optimistic, and said that he has a few ideas to refine the design, and welcomes any input from the community. This isn’t even the only new and interesting approach to resin printing we’ve seen in the last few weeks, so we share [Jón]’s optimism that the FDM Resin Printer will work (someday, at least).

Continue reading “Extruded Resin FDM Printing (With Lasers!)” →

The Silent Dripper Dispenses Water Without Making Any Sound

November 19, 2021 by 6 Comments

Engineering is all about making a design that conforms to a set of requirements. Usually those are boring things like cost, power consumption, volume, mass or compatibility with existing systems. But sometimes, you have to design something with restrictions you might have never considered. [Devon Bray] was tasked with designing a system that could dispense single drops of water, while making absolutely no noise. [Devon]’s blog describes in detail the process of making The Silent Dripper, which was needed for an art installation called The Tender Interval by [Sara Dittrich].

The design process started with picking a proper pump. Centrifugal pumps can be very quiet due to their smooth, continuous motion, but are not suitable for moving small quantities of liquid. Peristaltic pumps on the other hand can generate single drops of liquid very accurately, but their gripping-and-squeezing motion creates far more sound. [Devon] still went for the latter type, and eventually discovered that filling up the pumping mechanism with lithium grease made it quiet enough for his purpose.

The pump was then mounted on a 3D-printed bracket that also contained the water feeding tube and electrical connections to the outside world. The tubing was fastened with zip ties to stop it from moving when the pump was running, and the pump itself was isolated from the bracket with rubber dampening mounts.

Another trick to silence the pump was the motor driver circuit: standard PWM drivers often cause audible whine from the motor coils because of their abrupt switching, so [Devon] went for a Trinamic SilentStepStick that regulates the current much more smoothly. The end result is a water dripper that makes less noise than a piece of tissue paper being crumpled, as you can observe in the video (embedded below) which also demonstrates the complete art installation.

We really like the mechanical design of the Dripper; as far as we’re concerned it would merit a spot in a gallery on its own. It would not be the first water dripping art project either; we’ve already seen a sculpture that apparently suspends droplets in mid-air. Continue reading “The Silent Dripper Dispenses Water Without Making Any Sound” →

Automating Pool Monitoring And Chemical Dosing

October 23, 2021 by 7 Comments

Anyone who has had a backyard pool will know that it only takes a little lapsed attention to turn the whole thing green. For those sick of having to stay on top of things, the idea of automating pool care may be attractive. This project from [Discreet Mayor] hopes to do just that.

Data is graphed for easy analysis using Grafana.

The project uses a TI SimpleLink wireless-enabled microcontroller to run the show, which allows data to be offloaded to a base station for graphing with Grafana. The system can monitor pH levels as well as ORP (oxidation/reduction potential) levels using probes attached via BNC connectors. Based on these readings, the device can dose chlorine into the pool as needed using a peristaltic pump driven by a TI DRV8426 stepper motor driver.

We’d want to keep a close eye on the system for some time, making sure it wasn’t over or underdosing the pool with chemicals. However, that’s easy enough to do when all the data is logged neatly in a web-accessible graph.

We’ve seen other hackers implement similar controls to their own pools, too. If you’ve been working on your own home automation projects, be sure to drop us a line.

Automated Watering Machine Has What Plants Crave: Fertilizer

May 14, 2021 by 19 Comments

We’ve seen countless automated plant care systems over the years, but for some reason they almost never involve the secret sauce of gardening — fertilizer. But [xythobuz] knows what’s up. When they moved into their new flat by themselves, it was time to spread out and start growing some plants on the balcony. Before long, the garden was big enough to warrant an automated system for watering and fertilizing.

This clever DIY system is based around a 5L gravity-fed water tank with solenoid control and three [jugs] of liquid fertilizer that is added to the water via peristaltic pump. Don’t worry, the water tank has float switches, and [xythobuz] is there to switch it off manually every time so it doesn’t flood the flat.

On the UI side, an Arduino Nano clone is running the show, providing the LCD output and handling the keypad input. The machine itself is controlled with an ESP32 and a pair of four-channel relay boards that control the inlet valve, the four outlet valves, and the three peristaltic pumps that squirt out the fertilizer. The ESP also serves up a web interface that mimics the control panel and adds in the debug logs. These two boards communicate using I²C over DB-9, because that’s probably what [xythobuz] had lying around. Check out the demo video after the break, and then go check on your own plants. They miss you!

Don’t want to buy just any old peristaltic pumps? Maybe you could print your own.

Continue reading “Automated Watering Machine Has What Plants Crave: Fertilizer” →

Liquid Lite Brite Robot

March 3, 2021 by 2 Comments

Liquid handling workstations are commonly used in drug development, and look like small CNC machines with droppers on the ends which can dispense liquid into any container in a grid array. They are also extraordinarily expensive, as is most specialty medical research equipment. This liquid handling workstation doesn’t create novel drugs, though, it creates art, and performs similar functions to its professional counterparts at a much lower cost in exchange for a lot of calibration and math.

The art is created by pumping a small amount of CMYK-colored liquids into a 24×16 grid, with each space in the grid able to hold a small amount of the colored liquid. The result looks similar to a Lite-Brite using liquids instead of small pieces of plastic. The creator [Zach Frew] created the robot essentially from scratch using an array of 3D printers, waterjets, and CNC machines. He was able to use less expensive parts, compared to medical-grade equipment, by using servo-controlled valves and peristaltic pumps, but makes up for their inaccuracies with some detailed math and calibration.

The results of the project are striking, especially when considering that a lot of hurdles needed to be cleared to get this kind of quality, including some physical limitations on the way that the liquids behave in the first place. It’s worth checking out not just for the art but for the amount of detail involved as well. And, for those still looking to scratch the 90s nostalgia itch, there are plenty of other projects using the Lite Brite as inspiration.

Thanks to [Thane Hunt] for the tip!