A Cheap DIY PLC Based On The Atmega328P

August 22, 2024 by Lewin Day 41 Comments

If you’re running a big factory, you’ve probably got a massively expensive contract with a major programmable logic controller (PLC) manufacturer. One shudders to think about the cost of the service subscription on that one. If you’re working on a smaller scale, though, you might consider a DIY PLC like this one from [Mr Innovative.]

PLCs are rarely cutting-edge; instead, they’re about reliability and compliance with common industry standards. To that end, this design features the ATmega328P. Few other microcontrollers are as well understood or trusted as that one. The device is compatible with RS232 and RS485 and will run off 24 VDC, both of which you would find in a typical industrial environment. It offers 24 V digital inputs and outputs, as well as analog inputs and outputs from 0 to 10 V. [Mr Innovative] demonstrates it by hooking up a DWIN human-machine interface (HMI) for, well… human interaction, and a variable frequency drive to run a motor.

If you want to run a basic industrial-lite system but can’t afford the real industrial price tag, you might enjoy tinkering around at this level first. It could be a great way to get a simple project up and running without breaking the bank. Video after the break.

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Autofeeding CNC Lathe Cranks Out Parts All By Itself

January 23, 2024 by Dan Maloney 18 Comments

The trouble with building a business around selling low-margin widgets is that you have to find a way to make a lot of them to make it worth your while. And if the widget in question is labor-intensive to make, you’ve got to find ways to reduce your inputs. That sounds like a job for industrial automation, a solution that’s often out of reach of small shops, for all the obvious reasons. Not if you’re clever about things, though, as this fully automated CNC lathe work cell shows.

This build comes to us from the woodshop of [Maher Lagha], where he’s making wooden honey dippers. Wooden dowel blanks are dispensed from an infeed rack and chucked between centers on the headstock and pneumatic tailstock. A two-axis stage in front of the workpiece moves a tool against the spinning stock, carving out the honey dipper in just a few minutes. When the lathe work is done, the spindle stops, the tailstock pulls the honey dipper back off the headstock, and a pneumatic piston unceremoniously whacks the almost-finished part — it looks like it still needs a little manual post-processing — into a bin. Lather, rinse, repeat, profit.

[Maher] doesn’t provide many details, but just looking at the work cell shows a veritable feast of industrial automation equipment. The spindle and tailstock of the lathe sit on a bed made from a massive slab of aluminum extrusion, and the X- and Y-axes use linear rails and ballscrews. And mindful of the effects of wood chips on delicate mechanisms, [Maher] did a good job of containing the mess with a host of acrylic guards.

As we said when we saw [Maher]’s wooden coaster work cell a while back, the wood widget business must be pretty good to justify automation like this. What’s nice with both these rigs is that they look like they could be quickly reprogrammed and retooled to create other products. Pretty impressive.

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Humble Arduino As PLC

October 19, 2023 by Bryan Cockfield 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.

Industrial Robot Gets Open-Source Upgrade

May 14, 2023 by Bryan Cockfield 15 Comments

Industrial robots are shockingly expensive when new, typically only affordable for those running factories of some sort. Once they’ve gone through their life cycle building widgets, they can be purchased for little more than scrap value, which is essentially free compared to their original sticker price. [Excessive Overkill] explains all of this in a video where he purchased one at this stage to try to revive, but it also shows us how to get some more life out of these robots if you can spend some time hunting for spare parts, installing open-source firmware, and also have the space for a robot that weighs well over a thousand kilograms.

This specific robot is a Fanuc R2000ia with six degrees of freedom and a reach of over two meters. Originally the plan was to patch together a system that could send modern gcode to the Fanuc controller, but this was eventually scrapped when [Excessive Overkill] realized the controller that shipped with this robot was for an entirely different machine and would never work. Attempts to find upgraded firmware were frustrated, and after a few other false starts a solution was found to get the robot working again using LinuxCNC and Mesa FPGA cards, which have built-in support for Fanuc devices like this.

More after the break…

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The Mystery Of Automatic Lubricators Is Revealed

June 30, 2022 by Lewin Day 14 Comments

Industrial machines have all kinds of moving parts that require regular lubrication in order to prevent wear and damage. Historically, these would require regular visits from maintenance personnel to keep them greased up and slippery. Automatic lubricators eliminate that job by regularly dosing machines with fresh grease, and [Big Clive] decided to see what makes them tick.

The device can be set to deliver a full load of grease over a period of 1-12 months.

The simplest models merely use a spring to slowly force grease out over time. Changing the spring changes the rate at which grease is dispensed. Chemical versions exist too. A chemical pill is selected and inserted into a chamber with liquid, which releases gas over time. As gas is released, it creates pressure which forces a plunger down, dispensing grease over time.

Perhaps the fanciest versions are the electronic models, however, which have a dial on the back for selecting the rate of grease delivery. Turning the dial changes a resistance that is connected across two zinc-air cells which are sealed. Apparently, when current is forced through these cells and they’re excluded from oxygen, the cells liberate hydrogen gas, according to a patent [Big Clive] found. This then forces down the plunger, dispensing the grease. Turning the dial changes the resistance, changing the rate at which grease is dispensed.

The quest for labor saving in industry has produced multiple designs of automated lubricator, all of which are fantastically simple and optimised for purpose. It shows just how much can be achieved with a few components and some creative thinking, where one’s first impulse might be to reach for a timer or microcontroller to do the job.

Lubrication is incredibly important – don’t forget it when building your CNC machines! Video after the break.

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Scratch-Built Robot Arm Looks Like Something Off The Factory Floor

April 10, 2021 by Dan Maloney 13 Comments

[Jeremy Fielding] is rightly impressed with the power and precision of industrial robot arms. The big arms that you see welding cars on assembly lines and the like are engineering feats in their own right, which is why his leap into scratch-building one in the home shop promises to be quite an adventure, and one we’re eager to follow.

From the look of the video below, [Jeremy]’s arm is already substantially complete, so it seems like he’ll be releasing videos that detail how he got to the point where this impressively large and powerful arm took over so much of his shop. He’s not fooling around here — this is a seven-axis articulated arm built from aluminum and powered by AC servos. [Jeremy] allows that some of the structural parts are still 3D-printed prototypes that he’s using to finalize the design before committing to cutting metal, a wise move as he notes that most of the metalworking skills he needs to complete the build are still fairly new to him. It still looks amazing, and we’re looking forward to the rest of the series to see how he got to this point.

We always appreciate [Jeremy]’s enthusiasm and presentation style, and we generally learn a lot from his videos. Whether it’s a CNC table saw, a homebrew dynamometer, or supersonically melting baseballs, his videos are always great to watch.

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Breathtaking Alarm Clock Looks Like It Came From A 1960 Fallout Shelter

August 10, 2020 by Mike Szczys 24 Comments

All the hardcore geeks have alarm clocks where the bell striker is a hard disk read head… or at least they’ll be building them after seeing this. [Senile Data Systems] created an industrial voltage alarm clock out of decade counters that looks like it was unearthed from a fallout shelter (machine translation).

At first glace you might mistake this for a binary clock since it uses a column of LEDs to indicate each digit of 24-hour time. It’s not, as each row corresponds to a pin on the CD4017 decade counters that make up the timekeeping circuit inside.

Thumb~~screw~~ wheel switches at the top of the bulky handheld unit are how the alarm time is set, triggering a bell along the top edge. The clock is driven by the 50 Hz line voltage and [SDS] tried using that AC to drive a solenoid as the striker on the prototype unit but it performed poorly. The use of a hard disk read head turns out to be the perfect striker, as heard in the video after the break. As for triggering from the decade counters, here’s what [SDS] told us about the design:

The switches’ outputs gets ANDed with a 10 Hz signal (on a 60 Hz grid it will become 12 Hz). This drives a slightly beefy transistor which in turn drives an electromagnet to hammer a bell which broke off my bicycle. Yes. This is a digital analog alarm clock. The clock portion is digital but the bell is analog and sounds like Grampa’s old wind up alarm clock.

The build came about when a cache of over 600 industrial LEDs (24 V – 48 V) fell into his lap. This makes the insides of the clock something to behold as point-to-point soldering connects the panel mount lights and all nine logic chips. Add in that transformer for getting the line voltage and we imagine this thing has quite a bit of heft to it.

If you’ve ever had an alarm with a wind-up bell you know there’s no better way to jolt yourself out of a peaceful slumber and into the chaos of the real world. If the gentle tinkle of the hard drive head isn’t enough for you, this fire bell alarm clock will certainly do the trick.

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