Whether you only dabble in electronics as a hobby or it’s your full-time job, there are few tools as indispensable as the multimeter. In fact, we’d be willing to bet nearly everyone reading this site owns at least one of them. But as common and mindbogglingly useful as they may be, they aren’t perfect. Even the high-end models will invariably have some annoyance that only reveals itself once you become intimately acquainted with it.
Most people would just live with those quirks, especially when dealing with a cheaper model. But not [John Duffy]. Deciding nothing but perfection would do, he took every favorite feature he’d ever run into while using other multimeters and combined them into his scratch-built HydraMeter. In the process, he managed to come up with a few new ideas that push this device into a league of its own.
Some of the features of the HydraMeter will look familiar. You might even have them on your own personal meter, such as the wireless removable display module. Other features you’ll wish your meter had, such as the removable cartridge on the front of the device that lets you rapidly swap out a burned fuse. On the other side of the spectrum, there are some esoteric features that might leave you scratching your head. The ability to tell exactly how the meter is configured at a glance thanks to its exclusive use of toggle switches has a certain hacker appeal, but it’s a tricky user interface for most folks.
While the overall design of the HydraMeter may be divisive, one thing we can all agree on is that getting the project to this state took incredible determination. Over the years we’ve only seen a handful of individuals attempt to develop their own multimeters, and even then, none of them approached this level of fit and finish. The fact that [John] has turned all that effort over to the community by releasing his design under the CERN license is truly admirable.
[John] brought the HydraMeter out to Pasadena back in November for Supercon, and it got quite a reaction. And if you don’t like the user interface, it’s not hard to imagine how you could change it. This project has unquestionably pushed the state of the art for open source multimeters forward, and we’re eager to see where it goes from here.
From just a glace: Great project!
I think that’d be a no-go for me but the ability to see the meters configuration at a glance triggered an idea:
Make the big turnswitch of ‘normal’ multimeters transparent and let the whole round window show the configuration – maybe with polarization letting only one symbol shine through or something.
I’m sure there are some applicable optical tricks.
Interesting design requirements. Interesting design.
Things I like:
Low-profile rocker switches.
Modularity/interchangeability of components
The license.
Things I do not like:
Low-profile rocker switches.
Modularity/interchangeability of components
I’m not sure you know the difference between “things I like” and “things I don’t like”…
Idk about anyone else but the rocker switches are completely indecipherable at a glance.
And so are Chinese, Japanese, and European Runic symbols till you learn them, or the Latin alphabet as used in English. Or to stick to more programming/maths type elements so are the logical conditional statements, quadratics, differentials…
Not looked into what all the switches actually mean yet, but if all the configuration is on those rocker switch then once you know it will be at a glance the same way you didn’t have to puzzle out every letter sound to make the words out in this post (at least assuming you are not just learning English). So at least in theory I can agree with that statement, and do consider it potentially superior.
May I be the grump to toss in a complaint about those #$ing 1&0 markings.
The 1 looks like an incomplete circuit (wire not connected to anything) and the 0 looks like a loop or completed circuit.
Damned things caused me a few headaches when they began to show up some years ago.
I remounted any so that the on/1 was up, whenever I had the opportunity, yes I found some that the on position was at the bottom.
As for portable equipment that you might view from any direction/orientation? Same treatment as the sidewise mounted ones.
When they are sideways mounted with no room to turn is a problem. Those I tended to scrape off the (1$0) markings and put fingernail polish on the switch face, red=off/stop, green=on/run. A sharpy to write Off & On beside of them sometimes too, in case of poor lighting or colorblindness.
If you are going to go that far, address color blindness and use either patterning, other colors, or both.
Perhaps it wouldn’t be as bad if the rocker switches were illuminated or had corresponding illuminated symbols.
Yeah, same. I’m not sure how it’s a selling point, i have a meter with a big dial surrounded by handy labels, and i can see exactly how the meter is configured by looking at that.
No, that’s just mode. Fancier meters have range, hold, or secondary modes indicated on the LCD. Cheaper ones might have a dial with eight billion modes on the dial, but then it’s less obvious.
It’d be interesting to try: I’d actually bet you get used to it super quick.
9th grade electronics lab circa mid-1960s, each student assembled a simple analog meter to have and to hold till death do you part. Fortunately, in my case, it was the meter that died first. I believe it measured DC, AC and ohms. I seem to recall that it chirped with continuity. You had to have a meter to diagnose AM radio faults on the exam. There were 20 lab stations with deliberately faulty radios, broken trace, cold solder joint, fake wire, etc.
Meanwhile when I was in school last decade the closest we got in 11th grade was one if those dumb light up quiz games made of foil strips and old flashlight bulbs… I was majorly disappointed they didn’t let me use my junk bin to make one out of wire and LEDs lol
Education is a joke these days…I paid 80k for an engineering degree from 2008 -2012…sadly most of my courses I already knew just from using multimeter in my parants garage on my own products as a kid. Sadly people today graduate from EE with a 4.0 and have no clue what a multimeter is much less how to use one.
We did something similar in 9th-grade electronics class. Our school had a great electronic program in the mid-70s. We also had a lot of great test equipment and a whole setup for learning ham radio and getting a license.
You should look at the gear HVAC techs use: lotsa sensors all linked vía BT to a tablet/phone all accesible with a swipe on the screen instead of throwing a web of cables all around the sick AC unit. Even replacing lost refrigerant is now a fire and forget affair.
Especially if it’s a flammable refrigerant
I can understand having rather specific requirements for a meter. The last two handheld meters I bought were each after much searching and comparing. Two of the critical requirements were that the test leads could be stored on the back of the meter, and that the continuity function either be alone in it’s selection, or be the primary if it shared with something like diode. That last one really made it difficult. The vast majority I looked at had diode as the primary and continuity as the secondary. I was quite spoiled by the Radio Shack that I used for years before it finally bit the dust.
But now I’ve got a manual range that fits the criteria, and later was able to find an auto-ranging that did as well. And then I went and bought one of those silly bench-top Bluetooth speaker DMMs (not that I use the speaker), and that’s pretty much my main meter now. But hey, at least when I push the continuity button, that’s the first thing that comes up.
No one in the real world uses the back storage no lead exists that let’s you its always 2 or 3 wraps and leads on the front. Of you hook them to the back they provide no usable spacing and just enough loop that a jigsaw blade screws them! What universe are you living in?
I use the back lead storage all the time. What a strange take.
That sounds like you have very similar preferences to me… What did you settle on in the end?
Those style rocker switches are notorious for getting dirty and causing all kind of grief. Anyone remember power supplies on computers with those? They could do more than just not turn on! A dirt catching basin with contacts in it covered mostly with something handled whilst getting your hands dirty. Blast out often with shop air.
or front-end
HY3131
https://www.hycontek.com/hy_mcu/DS-HY3131_EN.pdf
and intelligent beeper (synthesizer tones/ modulations) , continuity, voltage level…
ok for low voltage hobbyist tinkering – no way i’d trust it around arc flash potential equipment (hvac, substation work, etc).
Going to have to look into this in more depth, I’ve been needing a better meter for a while and the features mentioned here seem really complete.
While I agree the rockers are not user friendly I’d say that might just be a labelling issue.
I’m going to argue in favor for it because one of my biggest griefs with off-the-shelf meters is the damn knobs. On both cheap and expensive meters I’ve had those knobs lose contact and then the whole thing gets completely buggered cause it can’t tell what mode it’s in.
Just light pressure on the knob into the board would affect the contact. So I’m glad someone is at least trying something different.
Maybe someone needs to make a hall effect knob. It could be done with a magnetic absolute encoder and a 3D printed housing that provides the detents. That way it wouldn’t rely on physical contact for sensing which mode it is in and if the detents wear out then you just print another detent ring. The detents could even be magnetic too if you really wanted.
Just get a nice swiss made rotary switch. I’d love to know if that would be able to retrofit.
I would love something open source that replicates the ones Harbor Freight used to give away.
“Up to 150V”: so not usable on mains outside North America and Japan then?
https://en.wikipedia.org/wiki/Mains_electricity_by_country
Yes, 240v please.
As an electrician I hate shunt type current meters, for safety reasons I block that off on those multimeters or preferably I use clamp meters. I have seen a couple of accidents that could have ended a lot worse.
I’ll stick with my Fluke!
If it works, it’s a Fluke!
Considering how absurdly expensive fluke has become, I aint got one, and wont get one either, unless i can buy a second hand one for a reasonable price.
Interesting, although I’d be uncomfortable with those switches and would rather use bistable (step, latching) relays in place of them. Bistable relays need only temporary power, keep their state indefinitely, their state can be read, and can be driven by normal GPIOs and a bjt or mosfet. Once swapped the switches with step relays, one can build a range selector by using a normal incremental encoder and do the rest in software, then add some safety code that say activates the requested range only after the user presses the encoder button for one full second within the two seconds after the range was selected.
Just a quick 5 minutes idea, but should work.
Bistable relays are reasonably cheap and can be bought at the usual more reliable sources, roughly $2 to $5 for low power/voltage ones, a bit less on Aliexpress.
Is your last name Goldburg by chance? What an asinine way to cause failure points
A feature that I would like in a DMM is logging ability, whether for voltages, current, or about any of the multiple features of modern DMMs. That, with an easy way to download the logs to a computer (e.g. BLE, uSD, USB, etc.).
I do have a 30 year old Metex that will connect via RS-232, but not conveniently.
I think the port up front would be epic for connecting to automotive sensors and connectors. I love it!! If I had time I’d love to build one. 👍