Fertilizing Plants With A Custom 3D-Printed Pump

For all but the most experienced gardeners and botanists, taking care of the soil around one’s plants can seem like an unsolvable mystery. Not only does soil need the correct amount of nutrients for plants to thrive, but it also needs a certain amount of moisture, correct pH, proper temperature, and a whole host of other qualities. And, since you can’t manage what you can’t measure, [Jan] created a unique setup for maintaining his plants, complete with custom nutrient pumps.

While it might seem like standard plant care on the surface, [Jan]’s project uses a peristaltic pump for the nutrient solution that is completely 3D printed with the exception of the rollers and the screws that hold the assembly together. With that out of the way, it was possible to begin adding this nutrient solution to the plants. The entire setup from the pump itself to the monitoring of the plants’ soil through an array of sensors is handled by an ESP32 running with help from ESPHome.

For anyone struggling with growing plants indoors, this project could be a great first step to improving vegetable yields or even just helping along a decorative houseplant. The real gem is the 3D printed pump, though, which may have wider applications for anyone with a 3D printer and who also needs something like an automatic coffee refilling machine.

Liquid Lite Brite Robot

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!

DIY Lasers Hack Chat

Join us on Wednesday, October 7th at noon Pacific for the DIY Lasers Hack Chat with Les Wright!

It’s not too much of a reach to say that how we first experienced the magic of lasers sort of dates where we fall on the technology spectrum. For the youngest among us, lasers might have been something trivial, to be purchased for a couple of bucks at the convenience store. Move back a few decades and you might have had to harvest a laser from a CD player to do some experiments, or back further, perhaps you first saw a laser in high school physics class, with that warm, red-orange glow of a helium-neon tube.

But back things up only a few decades before that, and if you wanted to play with lasers, you had to build one yourself. It was a popular if niche hobby with a dedicated following of amateur physicists who scrounged around for the unlikely parts needed: ruby rods, quartz-glass tubes, and exotic dyes. Couple them together with high-voltage power supplies, vacuum pumps made from converted refrigerator compressors, and homemade optical benches, and if the stars aligned, these parts could be coaxed into producing a gloriously intense burst of light, which as often as not hooked its creator as a lifelong laser addict.

We’re not sure which camp Les Wright falls into, but from the content of his growing YouTube channel, we’d say he’s caught the laser bug. We recently took a look at his high-performance nitrogen laser, which he’s been having fun with as the basis for a tunable dye laser. Along the way he’s been necessarily mucking around with high-voltage power supplies, oscilloscopes, and the occasional robot or two.

Les will stop by the Hack Chat to talk about everything going on in his lab, with a focus on his laser experiments. Join us with your questions on DIY lasers, and stop by to pick up some tricks that might help you catch the laser bug too.

join-hack-chatOur Hack Chats are live community events in the Hackaday.io Hack Chat group messaging. This week we’ll be sitting down on Wednesday, October 4 at 12:00 PM Pacific time. If time zones baffle you as much as us, we have a handy time zone converter.

Click that speech bubble to the right, and you’ll be taken directly to the Hack Chat group on Hackaday.io. You don’t have to wait until Wednesday; join whenever you want and you can see what the community is talking about.

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Eight Motors Can Sure Pump A Lot Of Water

Once upon a time, 3D printing was more of a curiosity than a powerful tool, with many printing trinkets and tchotchkes rather than anything of real use. However, over the years as technology and techniques have progressed, we now see more application-ready builds. This water pump from [Let’s Print] is a great example.

The pump consists of two major pieces – a drive unit, and an impeller. The drive unit consists of a gearbox that combines the power of eight electric motors, driving a single shaft. This is all achieved with striking yellow ABS gears in a black housing. The build video does a great job of explaining how to make the project work with different motors, and how to properly use the bolt adjuster to set the backlash on the gear train. The drive unit is then used to turn a 3D-printed impeller pump which is capable of delivering a great deal of water very quickly.

When fired up, the leaky assembly makes an awful racket and a huge mess, but sure as heck shifts a lot of water while it does so. Watching the water spray off the gears as it leaks through the bearings is a great sight, and it’s clear that the device works well. We’d love to see a cost and performance analysis of this pump versus a commercial offering.

While it’s certainly not the most rugged build, it’s a fun one that nevertheless gets the job done. We’d love to see this running a foam machine or a classic slip and slide. Video after the break.

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This LEGO Air Conditioner Is Cooler Than Yours

What’s the coolest thing a person can build with LEGO? Well it’s gotta be an air conditioner, right? Technically, [Manoj Nathwani] built a LEGO-fied swamp cooler, but it’s been too hot in London to argue the difference.

This thoroughly modular design uses an Arduino Uno and a relay module to drive four submersible pumps. The pumps are mounted on a LEGO base and sunk into a tub filled with water and ice packs. In the middle of the water lines are lengths of copper tubing that carry it past four 120mm PC case fans to spread the coolness. It works well, it’s quiet, and it was cheap to build. Doesn’t get much cooler than that.

[Manoj] had to do a bit of clever coupling to keep the tubing transitions from leaking. All it took was a bit of electrical tape to add girth to the copper tubes, and a zip tie used as a little hose clamp.

We think the LEGO part of this build looks great. [Manoj] says they did it by the seat of their pants, and lucked out because the copper and plastic tubing both route perfectly through the space of a 1x1x1 brick.

DIY cooling can take many forms. It really just depends what kind of building blocks you have at your disposal. We’ve even seen an A/C built from a water heater.

Compile A Hydroponics System From Source

Tending to a garden is usually a rewarding endeavor, as long as there is good soil to work with. If there isn’t, it can either get frustrating quickly having to deal with soils like sand or hard clay, or it can get expensive by having to truck in compost each year. Alternatively, it’s possible to set up systems of growing plants that don’t need any soil at all, although this requires an automated system otherwise known as hydroponics to manage water and nutrients sent to the plants.

This setup by [Kyle] is unique in that it uses his own open-source software which he calls Mycodo to control the hydroponic system. It is loaded onto a Raspberry Pi 4 (which he notes can now be booted from a USB drive instead of an SD card) which controls all of the peripherals needed for making sure that the water has the correct amount of nutrients and chemical composition.

The build is much more than just a software control panel, though. [Kyle] walks through every part of setting up a small hydroponic system capable of effectively growing 15-20 plants indoors. He grows varieties of lettuce and basil, but this system can work for many more types of plants as well. With just slight variations, a similar system can not only grow plants like these, but fish as well.

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Hands-Free Oreo Dispenser, Now With Milk

A while back, [Emiel] aka [The Practical Engineer] created a hands-free Oreo dispenser for his shop. This was a necessary addition to his fleet of handy tools, and allowed him to multitask much more effectively by using a sander, for example, at the same time that he needed to eat a cookie. Of course, this time-saving device was missing one crucial element: milk. [Emiel] is back in this video to show off his milk-dispensing upgrade to his original Oreo dispenser.

A few ideas were considered before [Emiel] decided to build a separate unit for the milk dispenser, so as not to create a gigantic mess any time an Oreo was delivered, and also to maintain some decorum in the shop. He rebuilt the Oreo dispenser with a 3D printer and then also 3D printed the milk dispenser. The chin-activated switch inside the device turns on a small pump which squirts milk into the user’s mouth, presumably after an Oreo has been delivered.

There are a few problems with the build, but most are easily solved by replacing non-food-grade parts with plastic that is more safe for being around consumables. The only other thing we can see here is that it might be a little hard to keep things clean, both inside and out, but most Oreo-related builds like this one have at least some problem with cleanliness that isn’t impossible to keep up with.

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