Modular portable conveyor belt

When teaching Industrial Automation to students, you need to give them access to the things they will encounter in industry. Most subjects can be taught using computer programs or simulators — for example topics covering PLC, DCS, SCADA or HMI. But to teach many other concepts, you  need to have the actual hardware on hand to be able to understand the basics. For example, machine vision, conveyor belts, motor speed control, safety and interlock systems, sensors and peripherals all interface with the mentioned control systems and can be better understood by having hardware to play with. The team at [Absolutelyautomation] have published several projects that aim to help with this. One of these is the DIY conveyor belt with a motor speed control and display.

This is more of an initial, proof of concept project, and there is a lot of room for improvement. The build itself is straightforward. All the parts are standard, off the shelf items — stuff you can find in any store selling 3D printer parts. A few simple tools is all that’s required to put it together. The only tricky part of the build would likely be the conveyor belt itself. [Absolutelyautomation] offers a few suggestions, mentioning old car or truck tyres and elastic resistance bands used for therapy / exercise as options.

If you plan to replicate this, a few changes would be recommended. The 8 mm rollers could do with larger “drums” over them — about an inch or two in diameter. That helps prevent belt slippage and improves tension adjustment. It ought to be easy to 3D print the add-on drums. The belt might also need support plates between the rollers to prevent sag. The speed display needs to be in linear units — feet per minute or meters per minute, rather than motor rpm. And while the electronics includes a RS-485 interface, it would help to add RS-232, RS-422 and Ethernet in the mix.

While this is a simple build, it can form the basis for a series of add-ons and extensions to help students learn more about automation and control systems. Or maybe you want a conveyor belt in your basement, for some reason.

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Mod Your Camera With ModBus

Industrial hardware needs to be reliable, tough, and interoperable. For this reason, there are a series of standards used for command & control connections between equipment. One of the more widespread standards is ModBus, an open protocol using a master-slave architecture, usually delivered over RS-485 serial. It’s readily found being used with PLCs, HMIs, VFDs, and all manner of other industrial equipment that comes with a TLA (three letter acronym).

[Absolutelyautomation] decided to leverage ModBus to control garden variety digital cameras, of the type found cluttering up drawers now that smartphones have come so far. This involves getting old-school, by simply soldering wires to the buttons of the camera, and using an Arduino Nano to control the camera while talking to the ModBus network.

This system could prove handy for integrating a camera into an industrial production process to monitor for faults or defective parts. The article demonstrates simple control of the camera with off-the-shelf commercial PLC hardware. Generally, industrial cameras are very expensive, so this hack may be useful where there isn’t the budget for a proper solution. Will it stand up to industrial conditions for 10 years without missing a beat? No, but it could definitely save the day in the short term for a throwaway price. One shortfall is that the camera as installed will only save pictures to its local memory card. There’s a lot to be said for serving the images right to the engineer’s desk over a network.

We’ve seen [Absolutelyautomation]’s work before – check out this implementation of Pong on an industrial controller.

PLC and Linear Actuators Automate Double-Hung Windows

Very few residential architectural elements lend themselves to automation, with doors and windows being particularly thorny problems. You can buy powered doors and windows, true, but you’ll pay a pretty penny and have to go through an expensive remodeling project to install them. Solving this problem is why this double-hung window automation project caught our eye.

Another reason we took an interest in this project is that [deeewhite] chose to use a PLC to control his windows. We don’t see much love for industrial automation controllers around here, what with the space awash in cheap and easy to use microcontrollers. They have their place, though, and a project like this is a good application for a PLC. But the controller doesn’t matter at all if you can’t move the window, for which task [deeewhite] chose 12V linear actuators. The fact that the actuators are mounted in the center of the window is probably necessary given the tendency of sashes to rack in their frames and jam; unfortunately, this makes for a somewhat unsightly presentation. [deeewhite] also provides the ladder logic for his PLC and discusses how he interfaces his system with Alexa, a WeMo and IFTT.

We’d love to see this project carried forward a bit with actuators hidden under the window trim, or a rack and pinion system built into the window tracks themselves. This is a pretty good start and should inspire work on other styles of windows. While you’re at it, don’t forget to automate the window blinds.

[via r/DIY]

OpenPLC is Ready for Hacking

It’s been nearly four years since we covered [Thiago]’s OpenPLC project. He never stopped working on it, and now it’s in a highly polished state.

If you read our initial coverage of this project, it would be easy to assume that he just wanted to control some halloween decorations. He is actually a PhD student at the University of Alabama in Huntsville. His research topic is SCADA (aka Industrial Control Systems) cyber security. His goal was to find vulnerabilities in PLCs and, hopefully, fix them. However, no PLC manufacturer releases their source code, and he was having trouble getting a deep understanding of something so closed.

So, since no one was going to open their code and hardware for him he simply made his own. OpenPLC can be programmed in all 5 IEC 61131-3 languages: ST, IL, LADDER, FBD and SFC. On top of that, it lowers the barrier of entry to developing this kind of industrial hardware by being compatible with all the favorites Arduino, Raspberry Pi, Windows, Linux, etc.

“The OpenPLC is the first fully functional standardized open source PLC. We believe that opening the black-box of a PLC will create opportunities for people to study its concepts, create new technologies and share resources.”

Pong on Industrial Controllers

Programmable Logic Controllers (PLCs) are a staple of control automation. Sometime in the 60s or 70s, they replaced a box full of relays to implement the kind of “if-this-then-that” logic that turns thermostats on or directs machinery. Sometime in the 90s or 2000s, some more computing power was added, giving us the Programmable Automation Controller (PAC). And if reading Hackaday has taught us anything, it’s that if you give people a little bit of computing power, they’ll implement Pong (or Snake or Doom!).

We were sent a link where [AbsolutelyAutomation] does just that: implements a remotely-playable Pong on a bit of industrial control. Even if you don’t have a PAC sitting around, the details are interesting.

The first step is to get graphics out of the thing. The PAC in question is already able to speak Ethernet, so it’s “just” a matter of sending the right packets. Perhaps the simplest way to go is to implement the remote framebuffer (RFB) protocol from VNC, and then use a VNC client on the PC to send the graphics. (As they point out [CNLohr] has done this quite nicely on the ESP8266 (YouTube) as well.) So an RFB library was written. [AbsolutelyAutomation] points out that this could be used to make boring things like user-friendly configuration and monitoring screens. (Yawn!)

Graphics done, it’s easy to add a Pong layer over the top, using the flowchart-based programming interface that makes homage to the PLC/PAC’s usual function as an industrial controller. (Oddly enough, it seems to compile to a Forth dialect to run on the PAC.) And then you’re playing. There’s code and a (PDF) writeup available if you want more info. If you don’t have a PAC to run it on, the manufacturers have a simulator for you.

We’ve never worked with a PLC/PAC, but we know the hacker spirit when we see it. And making something that’s usually located in the boiler room play video games is aces in our book. This sparks a memory of an industrial control hacking room at DEF CON a few years back. Maybe this is the inspiration needed to spend some time in that venue this year.

We know we’ve got controls engineers out there. What’s the strangest thing you’ve programmed into a PLC?

Reading Smart Cards from a PLC (with a Little Arduino Help)

If you’ve spent any time on a factory or plant floor, it is a good bet you’ve run into PLCs (Programmable Logic Controllers). These are rugged computers that do simple control and monitoring functions, usually using ladder logic to set their programs. [plc4u] wanted to connect a smart card reader to an Allen Bradley PLC, so he turned to an Arduino to act as a go-between.

The Arduino talks to a USB card reader using a USB host shield. Then it communicates with the PLC using an RS232 link and the DF1 protocol that most Allen Bradley PLCs understand. You may not need a smart card, but once you know how to communicate between an Arduino and the PLC, you could do many different projects that leverage other I/O devices and code available on the Arduino and connects to existing PLC installations. Just remember that you’ll probably need to ruggedize the Arduino a bit to survive and be safe to the same level as a PLC (which might include a NEMA enclosure or even an explosion-proof box).

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Hackaday Links: November 15, 2015

There are a surprising number of Raspberry Pis being used in industrial equipment. This means the Arduino is left behind, but no longer. There’s your PLCs that use Arduinos.

A few weeks ago, Google introduced a machine intelligence and computer vision technique that made the world look psychedelic. Now, this library is available. On another note, head mounted displays exist, and a sufficiently creative person could mash these two things together into a very, very cool project.

Welcome to Kickstarter! Kickstarter is an uphill battle. People will doubt you because you don’t have a ‘target audience’ or ‘the rights to this franchise’ or ‘any talent whatsoever’, but that’s what crowdfunding is for!

Several years ago, Apple shipped a few million 17″ iMacs with defective displays. They’re still useful computers, though, especially if you can find a replacement LCD. Apple, in all its wisdom, used a weird connector for this LCD. Here’s the adapter board, and this adapter will allow displays running up to 1920×1200.

[Jan] has earned a reputation of building some very cool synths out of single ARM chips. His previous build was a Drumulator and now he’s shrinkified it. He’s put four drum sounds, pitch CV, and audio out on an 8-pin DIP ARM.

YouTube gives you cadmium! [AvE], recently got 100,000 subscribers on his YouTube channel. Apparently, YouTube sends you a terrible belt buckle when you manage to do that. At least he did it without playing video games and screaming.