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.
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!
Search on Ebay for “TP4056 Protection”, change the charge current, add a 1,5V LDO and a LIR2032.
That should be pretty small.
My callipers have a CR2032 chemical cell.
You might like to check the energy storage of a lithium rechargeable as it might be much lower than a non-rechargable.
Yeah rechargable lithium buttons are preeetty small.
Would a solar cell work? Like the ones in calculators? Maybe a supercap… Hmm
Looks liek we posted at the same time with the same idea. You beat me to thew punch though.
Single solar cell, no.
They do not put out enough voltage, you need at least two and a charging circuit for the super cap.
I use these solar calipers for 3D printing work: https://item.taobao.com/item.htm?id=531887552063 cheap, lightweight, no sharp bits to poke you and accurate enough for 3DP at least. There’s also these metal solar ones: https://item.taobao.com/item.htm?id=35019100622 but they are more expensive and I’ve never used them.
There are solar calipers. Mitutoyo Solarmatic and other chinese cheap calipers.
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.
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.
Of course, this could have been solved a thousand ways, the obvious one, ordering new ones of Ebay for 8€ including shipping with a case of button cells.
Just get a nice vernier caliper. I haven’t had a battery die in mine yet.
Agreed. I never run out of batteries on my dial calipers or manual micrometers either.
I too found a dial caliper on sale and decided to give it a shot and found it to be quite accurate, and of course never running out of power.
Not to mention the effects of thermal changes on accuracy avoided by using a simple vernier caliper.
Not as good as mine version. No 3D printer needed and also much more compact design.
http://blog.chupasweb.net/archives/918
That’s how it’s done.
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!
Lol, title.
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.
Uh oh.., I feel a metric/imperial war emerging here…
Pulees refrain from such low battles here!
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.
my cellphone is shoulder mounted and uses flipdots for the display…
My phone still connects to the wall, has a rotary dial and no display.
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.
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.
All my verniers have been either metric or imperial but never both scales.
Therefore either I’m a loser, or your statement is false.
Or both.
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.
Most calipers these days have external interfaces, so you could hook up a custom large display, like the way the shumatech DRO-350 does. A good weekend project.
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.
Proof that perfect is the enemy of good.
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.
You are a doo doo head!
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.
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.
well said.
Hacking the “not a hack” people.
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.
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.
I have some genuine Mitu calipers. They eat batteries just as good.
Seems the hack might be to keep the coin battery but add in a switch ??
This. I use my digital caliper infrequently, so i just remove the battery when i put it away.
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.
“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?
Sounds like mine. Still going strong. Now my digital protractor is another story.
I can tell you that button cells do in fact leak if you wait long enough, it takes a long time though, a very long time, many years.
While I most certainly do appreciate the solution to an annoying problem, I personally still prefer a good old vernier caliper. But to each their own! This is still a pretty neat hack. :)
Hack a caliper to have a display on both sides.
That would be usefull in many cases. Or at least have a display that can flip like some dslr cameras.
Thought: Why not use an E-ink display?
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..
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.
I take the battery out when not using.
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.
I was thinking in doing the same in my auto-darkening welding mask. Cause today it had low battery and i almost get blind.
I had to use the old fashion welding glass mask.
for windows users
copy image.jpg + files.rar hiddenfileimage.jpgthis 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
cat image.jpg file.rar image.jpg > hiddenfileimage.jpg
For Linux users
But i think some websites now check that. I remember someone complain in 4chan about that.
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.
FTA:
Just tape a pack of spare batteries inside the carry case it came in.
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.
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?)
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.
Ave has a video on the differences between Mitutoyo calipers real and fake: No matter whether you scored a real one or no, you’ll see some knockoffs in the pawnshops too from time to time. https://www.youtube.com/watch?v=KnDype-j3hk
Not if you buy old enough ones. I have had these for years now, longer than the fakes have been made.
I noticed the battery drain is happening only for the old models (like 5-10 years old).
Bought a new one about 3 years ago (for 10 USD) and it is still running on the same battery.
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.
…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.
No shit sherlock, i did not know that, thank you for coming to my rescue!
Using the serial port slot for mounting a switch is really nice idea. Thanks!
Real hack in the comments!
Here’s an example with a picture from [Mr Name Required], which looks quite neatly done (only the outside shown): https://hackaday.com/2023/06/22/inside-digital-calipers/#comment-6655029
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.
If you did this with those AAs that have a usb under battery cap that recharge by integral usb, you’d have rechargeable calipers that would be really nice
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!
*Best Hack: learn how to read mechanical caliper. I have never ever changed…
What even happened here? German autocorrect while typing in English?
Translating every German word to the English equivalent:
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.
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.
I’m pretty sure I just bought this exact model! Which is also already dead.. Silver oxide batteries don’t grow on trees.. Wish I had this pack.
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.
Mine doesn’t turn on automatically, and still eats batteries :-(
After reading all the comments, I think it’s about time I took it apart…
Even if they don’t have auto-on, cheap calipers are often designed to stay on with the screen off just to track position to avoid needing re-zeroing the next time you manually turn them on (i.e, turn the screen on). Expensive calipers use absolute encoders. I don’t know what the middle ground is, if there is any.
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.
Also, sure would be nice if these things had inductive charge!
Good idea for a column!
Here’s an example from me: I have this fan. It’s good and powerful, and not too loud, but the stand/mount doesn’t work properly. First, bolt threads bearing on the hole in the flattened tube isn’t so good. Second, the threaded inserts built into the cage are at an angle, so it’s hard to get the bolts in, and changing the fan’s angle requires the stand to flex unless the bolts are really loose (but then the rubbing between the threads and the smooth holes is even worse). Then, when you’ve gotten the bolts in, you realize there’s nothing to hold the fan at a set angle, so the motor’s weight results in it blowing upward. If you were to tighten the bolts to hold it by friction (which would need to be really tight because the motor is heavy), the cage would get bent and the bolts would stick way too far in, so the blades would collide with them. (Even just mounting the fan loosely needs care to avoid putting them in too far!)
I solved this, somewhat, by anchoring a strip of gaffer’s tape to the bottom of the cage and running that to the midpoint of the stand. I could adjust the angle by unsticking it from the stand and resticking it at a different point along the tape strip. (This was only temporary because I bought the fan to build into something, so I didn’t really need anything better, but anyone who bought this fan for use as designed would.)