Arduino Hacks

3039 Articles

Humble Arduino As PLC

October 19, 2023 by 33 Comments

On the surface, a programmable logic controller (PLC) might seem like nothing more than a generic microcontroller, perhaps outfitted to operate in industrial settings with things like high temperatures or harsh vibrations. While this is true to some extent, PLCs also have an international standard for their architecture and programming languages. This standard is maintained by the International Electrotechnical Commission, making it so that any device built under these specifications will be recognizable to control engineers and maintenance personnel worldwide. And, if you use this standard when working with certain Arduinos, this common platform can become a standard-compliant PLC as well.

The IDE itself supports programming ladder diagrams, functional block diagrams, and other programming systems covered under the IEC 61131-3 standard. Not only that, it allows the combination of these types of PLC programming with Arduino sketches. The system offers many of the perks of PLC programming alongside the familiar Arduino platform, and supports a number of protocols as well including CANOpen, Modbus RTU, and Modbus TCP. It can also be used for monitoring a PLC system, essentially adding IoT capabilities to existing systems, enabling continuous monitoring, debugging, and program updates.

While not every Arduino is a great platform to build a PLC around, there are a few available for those looking for a system a little less proprietary and a little more user-friendly than typical PLC systems tend to be. There’s a reason that PLCs are built around an international standard and generally have certain hardware in mind to run it, though, and this comparison of a Raspberry Pi with an off-the-shelf PLC goes into detail about why certain components aren’t good choices for PLCs.

2023 Halloween Hackfest: A Spooky Muscle-Brain Interface

October 16, 2023 by 4 Comments

What could be better than a Halloween decoration? Something more perennial, or even something that could also be found in a classroom or lab. Something like [Markus Bindhammer]’s spooky muscle-brain interface. It was inspired by a series called “Tales From the Loop” in which a character’s muscle electrical activity is measured in preparation to adjust his prosthetic hand.

Essentially, it does what you think it does: attach the sensors to your muscles, move them around, and watch the brain light up. [Markus] started with a children’s learning kit that involves molding the brain and discs out of red rubbery goop, the vertebrae out of plaster, and then assembling the whole thing.

Instead, [Markus] molded the brain and vertebrae in two-part silicone for durability, and used two-component colored epoxy for the discs.

As the inspiring series is set in the 80s (we assume the brown, dingy 80s and not the fun, neon 80s), [Markus] gave the enclosure/stand an appropriate color scheme. Inside that box there’s an Arduino Pro Micro, a Grove EMG detector, and a mini step-up converter module. And of course, under the brain, there’s a NeoPixel ring. Don’t miss the build and demo video after the break.

There are a ton of things you can do with blinkenlights for Halloween. How about a light-up candy slide, or a bucket that seems them coming?

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This 3D Printable Soldering Air Filter Really Sucks

October 14, 2023 by 24 Comments

If you solder (and we know you do), you absolutely need ventilation, even for that lead-free stuff. Fortunately, [tinyboatproductions] has gotten into air quality lately and is here to help you with their snappy 3D printed air-filtering design.

At the heart of this build is a 120 mm notoriously-quiet Noctua fan coupled with a carbon filter. It does what you’d think — position the fan the right way and it sucks the air through the filter, which catches all those nasty particles.

The only problem is that the Noctua uses PWM, so there’s no governing it with a just potentiometer. To get around this, [tinyboatproductions] introduced an Arduino Nano and a buck converter, both of which were admittedly a bit overkill. Now the speed can be controlled with a pot.

Once control of the fan was sorted, [tinyboatproductions] decide to add an OLED display to show the fan speed and power condition, which is a nice touch. Be sure to check out the build video after the break.

If this doesn’t have quite enough features for you, here’s one that’s battery powered.

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Because You Can: Linux On An Arduino Uno

October 13, 2023 by 26 Comments

There are a few “Will it run” tropes when it comes to microcontrollers, one for example is “Will it run Doom?“, while another is “Will it run Linux?”. In one of the lowest spec examples of the last one, [gvl610] has got an up-to-date Linux kernel to boot on a vanilla Arduino Uno. And your eyes didn’t deceive you, that’s a full-fat kernel rather than the cut-down μClinux for microcontrollers.

Those of you who’ve been around a while will probably have guessed how this was done, as the ATmega328 in the Uno has no MMU and is in to way powerful enough for the job. It’s running an emulator, in this case just enough RISC-V to be capable, and as you’d imagine it’s extremely slow. You’ll be waiting many hours for a shell with this machine.

The code is written in pure AVR C, and full instructions for compilation are provided. Storage comes from an SD card, as the ATmega’s meagre 32k is nowhere near enough. If you’re having a bit of deja vu here we wouldn’t blame you, but this one is reputed to be worse than the famous 2012 “Worst PC Ever“, which emulated ARM instead of RISC-V.

Thanks [Electronics Boy] for the tip!

Auto Xylophone Uses Homemade Solenoids

October 8, 2023 by 26 Comments

Want to play the xylophone but don’t want to learn how? [Rachad]’s automatic xylophone might be just the ticket. It uses homemade solenoids to play tunes under computer control. Think of it as a player piano but with electromagnetic strikers instead of piano keys. You can hear the instrument in action in the video below.

Since the project required 24 solenoids, [Rachad] decided to build custom ones using coils of wire and nails. We were amused to see a common curling iron used as an alternate way to apply hot glue when building the coils. The other interesting part of the project was the software. He now uses a toolchain to convert MIDI files into a serial output read by the Arduino. Eventually, he wants to train an AI to read sheet music, but that’s down the road, apparently.

Honestly, we were a bit surprised that it sounded pretty good because we understand that the material used to strike the xylophone and the exact position of the strike makes a difference. We doubt any orchestra will be building one of these, but it doesn’t sound bad to us.

The last one of these we saw did have more conventional strikers if you want to compare. Honestly, we might have just bought the solenoids off the shelf but, then again, we don’t make our own relays either.

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Smart Coffee Replaces Espresso Machine Controller With Arduino, Sensors

October 7, 2023 by 16 Comments

A common hacker upgrade to an espresso machine is to improve stability and performance with a better temperature controller, but [Schematix]’s Smart Coffee project doesn’t stop there. It entirely replaces the machine’s controller and provides an optional array of improvements for a variety of single-boiler machines (which is most of them).

Smart Coffee isn’t free, it costs 16 NZD (about 10 USD) but there is a free demo version. There is no official support, but there are wiring guides and sources aplenty from which to purchase the various optional parts. It runs on an Arduino MEGA 2560 PRO (or similar microcontroller) and supports a wide array of additional hardware including pressure transducer, water level sensor, flow meter, OLED display, and more.

Modification of one’s espresso machine is a rewarding endeavor, but the Smart Coffee project provides a way for one to get straight to the hacking and function modifying, instead of figuring out the wiring hardware interfacing from scratch.

We’ve seen [Schematix]’s work before with a DIY induction heater which showed off thoughtful design, and it’s clear he takes his coffee at least as seriously. Check out the highly comprehensive overview and installation video for Smart Coffee, embedded just below the page break.

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2023 Halloween Hackfest: Treat Trough Of Terror Is Actually Pretty Cute

October 3, 2023 by 7 Comments

Even though it seems the worst of COVID has passed, October generally kicks off cold and flu season, so why not continue to pass out Halloween treats in a socially-distanced fashion?

That is, of course the idea behind [Gord Payne]’s Halloween Treat Trough of Terror. Lay a treat at the top of the trough and it will activate the LED strips that follow the treat down to the end, as well as some spooky sounds. The treat in question is detected by an SR-04 ultrasonic distance sensor connected to an Arduino Nano.

All in all this was a highly successful build as far as neighborhood entertainment value goes. Toddlers stared in awe at the blinkenlights, teenagers proclaimed it ‘sick’, and we can only assume that the adults were likely happy to see something aimed at kids that’s not scary.

[Gord] has a nice how-to if you want to build your own, and of course, the Arduino sketch is available. Be sure to check it out in action after the break.

Don’t have room to build a treat slide? Here’s a socially-distanced dispenser that lets them stomp a giant button.

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