The Most Sensational Calipers On The Planet!

Everyone here probably has a pair of cheap Chinese calipers kicking around the workbench. This means everyone here also knows how quickly the batteries in these handy little tools die. [Thosnbn] also noticed this, but instead of simply complaining and wishing the problem would go away, he decided to do something about it. He built a battery pack for his calipers, giving this tool a two year battery life.

The idea for this build came after [thosnbn]  completely destroyed a pair of these cheap calipers. At the time, the fix was to tape a AA battery to the tool, and solder wires directly to the contact pads for the tiny button cell battery. This fix worked, and after dealing with the ugliest tool known to man for a few years, [thosnbn] decided to clean it up a little.

The new battery enclosure was designed in Fusion360, includes handy features like a switch, and is completely 3D printed. It took a few weeks for [thosnbn] to get all the parts to fit together correctly, but the end result is great. This battery pack fits neatly on the back of the calipers, holds a single AA battery, and the lid is tightly secured with a pair of machine screws.

Unfortunately, [thosnbn] chose to share this project on imgur, a site that does not support sharing .stl or other 3D printer files. It does, however, serve as inspiration for you to make your own battery pack for a pair of cheap calipers.

82 thoughts on “The Most Sensational Calipers On The Planet!

  1. Modifying a pair of cheap calipers to use more common batteries, or a lipo, is something I’ve been wanting to do for a long time. Maybe this will motivate me to actually get around to doing it!

    Nice hack!

    1. That’s hilarious. That’s EXACTLY what I did to a cheapo set about a year ago. I didn’t work so hot. It powers up under a lamp or sunlight, but will die pretty quick even with a 1F supercap in place of the button cell. The caliper still works, but it’s a pain. It was much better with the button cell.

  2. I like this but I wonder if it could have been done better with a button cell and a calculator solar cell. It would make for a smaller footprint plus you have the rechargeable aspect.

    1. Nice! A switch to actually turn the darn thing off is exactly what is needed, and like the guy said, no 3D printer needed. Heck, if I could afford a 3D printer, I would get a Fowler digital caliper instead of the crummy HF version.
      This is indeed a hack, bravo!

  3. Forget these battery powered calipers – they’er for losers. Learn how to read a real vernier caliper. It will never run out of battery power, and it’s a skill that will come in handy on lots of other machine tools.

      1. Eh… he most likely still uses a cellphone with a segment display as well.

        Both mechanical and electric have their pros and cons, i got mechanical and electric.
        I only use the electric 95% of the time.

          1. I just write notes on paper, stuff them in a bottle and toss them in the river. Takes a long time to get a reply, but….

            Vernier calipers make me itch. I have some giant one someplace when I just have to measure something big, but dial calipers, now they are the bomb.

      2. How so? Vernier calipers often come with imperial on top and metric scale on the bottom I understand.
        And obviously it’s best to have both since sometimes you need imperial and other times metric, it’s not always a choice you make if working with stuff you bought and are working on.

    1. I lost my verniers and bought a digital calliper just like the one in this article.

      My eyesight is dwindling now so I take a lot of pictures that I can zoom into on screen.

      One distinct advantage of the digitals is that I can take a picture of the callipers measuring something and the dimension is clearly visible on the LCD display on the computer. It’s an excellent way to store dimension for making PCB foot prints.

      Horses for courses I ‘spose.

      I will still buy another set of verniers though.

  4. I was using mine the other day and thinking as I replaced the batteries – again how much they would benefit from just having a mechanical switch fitted.

    Nice work on the case btw great effort for trying out your modeling software.

  5. I put leftover food in big ziplock backs before placing in fridge, is that a hack? Yes, should it be on hack a day, no, and neither should this…. I am seeming a trend from some of these authors, just put out an article to put out an article. There was a time where I could not get enough of hack a day, now it’s turning to poor articles about poor things being done poorly and for the hard way.

    1. Food in bags is not a hack.
      Getting sick of tapeing cells to a device, and then printing a case and showing others how you did it and where you failed is a hack. A sense of humor helps as well.

      If you don’t like an article, click “Report comment” on everyone. That will make you feel better.

    2. Back then perhaps these was only one ‘hack a day’. It’s Sunday and there have been four or five articles.

      I just read the main ‘blog’ page and some of the articles I don’t even open to look at. Shock, horror, surprise! Did you know you don’t have to read every one!

      If your commenting on an article page then your probably commenting to others that have some interest in the article.

      So to put it succinctly, I have no problem avoiding articles that *I think* are not a hack. Now I just have to find a way to avoid the *not a hack people*. *Not a hack* is getting old, it’s getting stale, it’s getting boring, it’s getting repetitive and quite frankly – it’s getting annoying.

      I hope that doesn’t come across the wrong way. Everyone’s opinion is valued here, it’s just some things are getting too repetitive.

  6. What happens is the cheap calipers never really turn off. I think the guy at eevblog showed this, and there’s articles on Hackaday on the same topic. I do have a 12″/300mm caliper that just drains batteries. What I do is pull the battery when I’m not using it. I don’t need it very often. I might even be on the originally included batteries.

    I’ve got several $50 Fowler 6″/150mm calipers whose 2032 batteries seem to last a couple years. If you treat them right they will last many years and you don’t have to worry about whether the batter

    For those recommending verniers, you do that. I’m sure they’re fine but I don’t care for them.

    1. aVe did a teardown on some counterfeit Mitu calipers off of eBay and found the current draw was almost the same whether they were turned on or off, he may have been copying Dave though… I know that he’s mentioned him before.

  7. get in the habit of locking the calipers when not in use, that stops a bump/vibration on the bench turning the display on.
    It increases battery life significantly, it’s been 3 to 4+ months since i’ve had to replace a battery and i use them a few times a week.

  8. “Replace them every year” say the comments? How wasteful, and where’s the fun in that? Practicalities aside, this is a good solution to a problem. However, if you really want to save money AND time, get one from iGaging. Less than $30, does fractions, very accurate and zero means zero every time. Even comes in a sturdy plastic case so toolbox accidents are prevented. I pull the battery when I don’t plan to use it for a while more to prevent damage from leakage than anything else. Not sure button cells leak but why take the chance?

        1. The display isn’t the issue, a LCD like that uses near zero power (used in watches too of course) and it turns off with the button and often when not used for a while, so that’s not the part that drains the battery.
          From this entire thread I’d say a good idea is to a.) convert to use a 2032 cell and b.) add a mechanical switch. combined this can keep it light and small and be able to fit in more tight spaces while still alleviating the battery drain issue..

    1. Now THAT would be extremely useful. I have begged for that to exist for years why doesnt it already? How hard would it be to do? also i love verniers. They arent hard to read at all. I swear by mitutoyo digitals though.

  9. I just use a couple of elastic bands made from old bike tubes to hold a AAA rechargeble to the back of the calipers. Wires solderd to the battery contacts are then held to the battery with one band along the battery. A blob of solder on the end of the wires makes for a larger contact area. The secon band holds the battery to the caliper display.

  10. for windows users
    copy image.jpg + files.rar hiddenfileimage.jpg
    this will insert rar file after image data but before EOF
    tell ppl to open the fullsize with winrar or 7zip
    may fail if imagur uses virus scan or caps the image size

      1. I don’t get how this is relevant. But anyway most dumb sh.t coders just check the file extension and not the mime type consequently most web sites are like this. Most browsers check the mime type to determine what to do with the data. So in most cases you can just change the file extension to something that is accepted by the website.

        So you can rename your text/javascript – payload.js to layout.css and you have XSS 101 or worse.

  11. Goodbye HaD for awhile, has nothing to do with this article or any article I assure you. Hopefully I come back with an .io page and all that. I love approximately 98% percent of you, maybe more. Keep hacking, keep exploring, take everything apart, yours truly, notarealemail.

  12. I have at least 2 pair of those stinking miserable Harbor Freight digital calipers. They work OK when you have a live battery in them, but ….. My life became so so much better when I just got a set of dial calipers. Never had a dead unit since. Quick and easy to use, reliable – basically a perfect tool.

    I admire this battery project, mostly because it might give a purpose to these otherwise useless lame and wretched digital calipers I have, but if I go that route it will probably be with them mounted to my mill as a DRO or some such, not for hand use. (Did I forget to mention how much I despise these digital calipers?)

  13. Nope, I have two pairs of Mitutoyo 6″ I picked up cheap at a pawn shops and an older set of 12″ Starrett from a surplus store. I dont worry about the batteries in those, they last years. The feel of a set of well made calipers blows this chinese crap out of the water.

    1. This was my observation as well.
      Also with the display “off” the electronics are still running.
      Others like a mechanical caliper, but in a dual use environment, you can’t beat that “mm/inch” button.

  14. …I almost feel a little bad this guy didn’t figure out the secret to why these things kill batteries so quickly. And that this comment will be lost in the sea.

    I have those exact calipers. The problem isn’t that the batteries are too small, the problem is that they run ALL THE TIME. The power button doesn’t actually turn it off; it just disables the LCD. The capacitive sensor keeps going (which is how they turn on automatically when moved), which is the majority of the current draw. According to my readings, when “on” the calipers draw about 21µA. When “off”…they’re still drawing 17µA. I cut and re-soldered a few traces on the circuit board, using the little serial out port to mount a switch to. This cuts power from the battery completely. They were draining a battery every 3 months or so before I did this. I haven’t changed the battery in over a year, now.

  15. Ugly is mine with 12ga. wire holding a AA to the front as well as forming the connections. Still fits into the plastic case, lasts years. It took only minutes to make. Thought I killed it twice, keeps on ticking.

  16. Besten Hack: lesen Höhe to read mechanical caliper. Habe neuer Eber changed a battery in a caliper. Why would you use something, that needs battery ober the same thing not needing batteries? I don’t get it!

  17. Well I would not do that to my expensive calipers just to give it a longer battery life.
    This is not a hack but a complete disaster. Who wants a big box sicking out of there caliper?. Oh and yes you can run a caliper of a single solar cell. I own one that works fine but they are just used for easy work. What’s next stick a car battery on it to get 100 years battery life out of them and regulate it from 12v to 1.5v or 3v lol. This tool is designed to be sleek and easy to use with nothing sticking out of it or on the side. Sorry thumbs down and a waste of time.

    1. if you have a proper expensive caliper you shouldn’t need this hack, the issue is some cheap calipers will only hold power for a day or two in the most extreme cases, they never turn off and sometimes they use power hungry components.

  18. I have two calipers that look exactly like the one pictured. I paid less than $15 each for them, and I love them. I’ve had the older of the two for a couple of years now, and it’s still on the original battery. I don’t know about the new one yet though. Although it looks the same, the behaviour is different – as soon as I move the ‘jaws’, the thing turns on. The older one doesn’t do that. So there are probably different electronics and/or different programs inside, and I can see how some might eat batteries while others don’t.

  19. I did the same thing with a digital angle meter and a CR123. Stupid meter used CR2032’s was dead every time I tried to use it (admittedly maybe twice a year). Now it’s ready any time.

    @Hackaday – you guys could create a new column called “retail sh&t I had to modify” for stuff like this. I had to modify a brand new rock tumbler to get it to work right; and a host of other things.

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