Compile A Hydroponics System From Source

June 16, 2020 by Bryan Cockfield 18 Comments

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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Linux-Fu: Automation For Chrome And The Desktop By Matching Screenshots

June 15, 2020 by Al Williams 11 Comments

I will be the first to admit it. This is almost not — at least not specifically — a Linux article. The subject? An automation tool for Chrome or Firefox. But before you hit the back button, hear me out. Sure, this Chrome plugin started out as a tool to automatically test web pages and automate repetitive tasks in the browser. However, it can extend that power to all programs on your computer. So, in theory, you can use it to graphically build macros that can interact with desktop applications in surprisingly sophisticated ways. In theory, anyway; there are a few problems.

The program has a few different names. Most documentation says UI Vision RPA, although there are some references to Kantu, which appears to be an older name. RPA is an acronym for Robotic Process Automation, which is an industry buzz word.

Let’s take it for a spin and see what it’s all about.

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No Corners Were Cut On This Arduino Circle Cutter

May 8, 2020 by Tom Nardi 9 Comments

Hackers always have their eye out for a good deal, so when [Gadget Reboot] saw a good price on square stickers he had to pull the trigger. There was just one problem: his logo is a circle. He could have rectified the problem with a pair of scissors on a lazy afternoon, but we think building an elaborate circle cutting machine was a much better use of his time.

But this project isn’t just for the Giotto wannabes. Even if you don’t find yourself in need of an infinite supply of perfect paper circles, the video after the break provides an excellent case study in getting stepper motors to do your bidding; whatever that might be. [Gadget Reboot] walks the viewer through the design and construction of a dual stepper motor controller that could be used for a multitude of tasks.

With an onboard Arduino Pro Micro, OLED display, and rotary encoder, this controller just needs some custom software to make your CNC dreams come true. [Gadget Reboot] is even using low-cost optical endstops in this build, which are a great non-contact way of making sure your machine doesn’t go out of bounds. That’s particularly important when the machine happens to be wielding a razor blade.

If you’re a thoroughly modern hardware hacker who prefers using a web browser to twiddling knobs, then perhaps you’d be interested in the WiFi enabled stepper motor controller we covered recently.

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A Honeycomb Patching Robot Powered By Arduino

March 3, 2020 by Tom Nardi 13 Comments

No, it’s not the kind of honeycomb you’re probably thinking of. We’re talking about the lightweight panels commonly used in aerospace applications. Apparently they’re rather prone to dents and other damage during handling, so Boeing teamed up with students from the California State University to come up with a way to automate the time-consuming repair process.

The resulting machine, which you can see in action after the break, is a phenomenal piece of engineering. But more than that, it’s an impressive use of off-the-shelf components. The only thing more fascinating than seeing this robotic machine perform its artful repairs is counting how many of its core components you’ve got laying around the shop.

Built from aluminum extrusion, powered by an Arduino Due, and spinning a Dewalt cut-off tool that looks like it was just picked it up from Home Depot, you could easily source most of the hardware yourself. Assuming you needed to automatically repair aerospace-grade honeycomb panels, anyway.

At the heart of this project is a rotating “turret” that holds all the tools required for the repair. After the turret is homed and the condition of all the cutting tools is verified, a hole is drilled into the top of the damaged cell. A small tool is then carefully angled into the hole (a little trick that is mechanical poetry in motion) to deburr the hole, and a vacuum is used to suck out any of the filings created by the previous operations. Finally a nozzle is moved into position and the void is filled with expanding foam.

Boeing says it takes up to four hours for a human to perform this same repair. Frankly, that seems a little crazy to us. But then again if we were the ones tasked with repairing a structural panel for a communications satellite or aircraft worth hundreds of millions of dollars, we’d probably take our time too. The video is obviously sped up so it’s hard to say exactly how long this automated process takes, but it doesn’t seem like it could be much more than a few minutes from start to finish.

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This Servo Actuated Multimeter Does The Twist

February 14, 2020 by Tom Nardi 9 Comments

This tip comes our way courtesy of [Elad Orbach], who’s been experimenting with a device that uses a servo to turn the function dial on a multimeter. It’s something you can put together in a few minutes with leftovers from the parts bin, and as you can see in the video after the break, the basic concept seems to be sound enough.

As to finding a practical reason for spinning the switch on your meter with a servo, that’s left largely as an exercise for the reader. [Elad] hints at the possibility of using such a setup to help automate repetitive testing, which we could see being useful especially in combination with a foot pedal that allows you to switch modes without having to put the probes down. The same basic idea could also be helpful as an assistive device for those who have difficulty grasping or limited dexterity.

Whether top of the line or bottom of the barrel, the multimeter is easily the hardware hacker’s most frequently used tool (beyond the screwdriver, perhaps). We’ve seen plenty of projects that try to graft additional features onto this common gadgets, though automation isn’t usually among them.

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Automated Cat Feeder Leaves Little To Chance

December 5, 2019 by Tom Nardi 11 Comments

We often like to say that if something is worth doing, then it’s worth overdoing. This automatic cat feeder built by [krizzli] is a perfect example of the principle. It packs in far more sensors and functions than its simple and sleek outward appearance might suggest, to the point that we think this build might just set the standard for future projects.

The defining feature of the project is a load cell located under the bowl, which allows the device to accurately measure out how much feed is being dispensed by weight. This allows the feeder to do things such as detect jams or send an alert once it runs out of food, as well as easily adjust how much is dispensed according to the animal’s dietary needs. To prevent any curious paws from getting into the machine while it’s doling out the food, the lid will automatically open and close during the filling process, complete with optical sensors to confirm that it moved as expected.

All of the major components of the feeder were printed out on a Prusa i3 MK3S, and [krizzli] says that the feed hopper can be scaled vertically if necessary. Though at the current size, it’s already packing around a week’s worth of food. Of course, this does depend on the particular feline you’re dealing with.

In terms of electronics, the feeder’s primary control comes from an ESP8266 (specifically, the Wemos D1 Mini), though [krizzli] also has a Arduino Pro Mini onboard so there’s a few more GPIO pins to play with. The food is dispensed with a NEMA 17, and a 28-BYJ48 stepper is in charge of moving the lid. A small OLED on the side of the feeder gives some basic information like the time until the next feeding and the dispensed weight, but there’s also a simple API that lets you talk to the device over the network. Being online also means the feeder can pull the time from NTP, so kitty’s mealtime will always be on the dot.

Over the years we’ve seen an incredible array of automatic cat feeders, some of which featuring the sort of in-depth metrics possible when you’ve got on onboard scale. But we can’t help but be impressed with how normal this build looks. If nothing else, of all the feeders we’ve seen, this one is probably the most likely to get cloned and sold commercially. They say it’s the most sincere form of flattery.

DIY Photo Backup In The Field

November 20, 2019 by Bryan Cockfield 29 Comments

They say a file isn’t backed up if it isn’t backed up twice. This is easy enough to do if you have access to your computer and a network, but if you’re a photographer you might end up in a place without either of these things and need a way to back up the files you just created. For that you’ll need a specialized photo backup tool which you can easily build yourself.

While commercial offerings are available which back up files locally from a camera’s SD card to another medium, they suffer from a high price. [André]’s solution can be had for a fraction of that cost. Using a Raspberry Pi Zero, a tiny USB hub, and a high capacity jump drive, a photographer can simply plug in an SD card and the Pi will handle the backups with varying levels of automation. The software that [André] made use of is called Little Backup Box written by [Dmitri Popov] and can be used typically as an automatic backup for any other device as well.

This is a great solution to backing up files on the go, whether they’re from a camera or any device that uses an SD card. Removable storage is tiny and easily lost, so it’s good to have a few backups in case the inevitable happens. Raspberry Pis are an ideal solution to data backup, and can even be battery powered if you’re really roughing it for a few days.