Vacuum Gauge Display; Arduino Replaces Industrial

Arduinos! They’re a great tool that make the world of microcontrollers pretty easy, and in [cptlolalot]’s case, they also give us an alternative to buying expensive, proprietary parts. [cptlolalot] needed a gauge for an expensive vacuum pump, and rather than buying an expensive part, built a circuit around an Arduino to monitor the vacuum.

pressure-gauge-thumbThis project goes a little beyond simple Arduino programming though. A 12V to 5V power supply drives the device, which is laid out on a blank PCB. The display fits snugly over the circuit which reduces the footprint of the project, and the entire thing is housed in a custom-printed case with a custom-printed pushbutton. The device gets power and data over the RJ45 connection so no external power is needed. If you want to take a look at the code, it’s linked on [cptlolalot]’s reddit thread.

This project shows how much easier it can be to grab an Arduino off the shelf to solve a problem that would otherwise be very expensive. We’ve been seeing Arduinos in industrial applications at an increasing rate as well, which is promising not just because it’s cheap but because it’s a familiar platform that will make repairs and hacks in the future much easier for everyone.

21 thoughts on “Vacuum Gauge Display; Arduino Replaces Industrial

    1. Probably a form of Power over Ethernet ( Usually POE is a lot higher voltage but if you do it custom you can make your own. Only danger these days is plugging that cable into a Gigabit ethernet port since Gigabit used all 8 wires. Otherwise 10/100 connections might not even have the pins in place making it safe to use that way. Might be best to mark the cable but I doubt it has any generic IP connection to it. Looks like it is just being used as a multipin cable.

      1. 10/100 Ethernet specification requires 8P8C connectors which have all pins, even if they are not used. The 10BASE-T specification sends differential voltages at +2.5 and -2.5 VDC (later specs use up to 2V). Due to static and grounding issues, it’s entirely possible that the sockets regularly handle 12V bursts with very low current. PoE uses 37-57V based on cable length (12 is too low due to voltage drop), and I’ve never heard of an issue connecting them to non-PoE devices, but that’s probably because PoE support (802.3af and 802.3at) is signalled using.

        Depending on how far this box is from the device in question, I would just use real PoE with an injector at one end and a breakout box at the other.

    2. RJ45 is just a connector, they are used for all sorts of things outside of ethernet. They are cheap and the cables are cheap and readily available. In the case of this project Edwards uses them on their Active Gauge sensors across the line so you can plug in a gauge head and the controller knows what it is and configures itself to read the analog signal coming from the sensor.

    3. cat5e is used for telephones, the ring votlage of a telephone is 90VAC.
      RJ45 is rated for 2.5A at 150V, I dont know if those are chinese units or not.
      (chineese volts/amps are smaller than north american ones, long story)

    4. Creator of the project here.
      The vacuum gauges this is designed for use RJ45 connector to supply power and data. As such, we have multiple gauges on various machines around our factory with cables going into them. I designed this device to fit between the existing factory cable and the gauge without requiring modification or extra cabling.

    1. Boo hoo. I’d love it if every device with a microcontroller inside used an Atmel processor and was compatible with the Arduino IDE. Can you imagine the hacks that we’d start to see?

  1. Hm, if I’m not mistaken he got all those parts from electrodragon- I recognize their boards. Neat stuff, and fairly well documented considering it’s a Chinese site.

    And that final product looks really polished. Beveled 3D printed cases look amazing.

    1. amazon has those green perf boards, too (of course). I just picked up a bag of 25 of them (4x6mm) for $15 or less. very nice plated thru holes, well centered and very flat boards. bye bye cheapie single-sided off-center holed rat-shack boards!

  2. too funny: just yesterday I did my first project with that very same blue oled display. had it sitting around for months and months and finally got around to wiring it up and doing some test code for it. I kind of like this little display, especially for $10 that it typically costs (amazon price).

    here I have the ‘unix cal’ style output (using no unix code, though):

    for this test, I’m also using the ESP wifi module and getting time/date from a webserver, so it auto-sets itself.

    only problem with those displays is that they are rated for 10k hours continuous which is just about a year. so, better socket that display since it will ‘burn out’ or go overly dim in not too long a period of time. still, $10 every year is not so bad; just make sure you don’t depend on these being bright for long-term duty.

    1. I wonder if you could get away with blanking it so it’s only one for some duty that the human eye wouldn’t notice too much without screwing with timing elsewhere? You might extend the life that way. Or simply add some sort of human interface, a button or proximity detector to only have it on when someone is looking at it.

    2. Wow, I’m glad I read your comment about lifetime rating of these displays, as I was about to use a bunch of them in a project! I like them because they’re not overly bright, but after knowing this, I might have to resort to the old trusty 16×2 and dim the backlight.

  3. For those that don’t know, it’s a Pirani gauge. Edwards do a neat line of “active” gauges, where all the electronics is contained within the gauge head itself, and simply output a 0-10V reading. I got a couple of those very same Pirani gauges yonks ago and they were very easy to use. Unfortunately rather expensive to buy new…..

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