You made something awesome! Glad you made it real and got past the one more feature trap we often fall into. Still lots of features in here in its current state. Need more of this in the world.
Thanks! Yeah, absolutely, there's like, a hundred changes and things I still want to do with this :) And I'll definitely get to every one of them in rev 2 🙃
Finally, someone who shares my passion for homemade devices. Very cool project, I have been making industry field calibration for myself (many revisions), and finding someone like you make me wanting to keep going with the next step, Bluetooth remote control. Very inspiring, thanks. Saluti from Italy
Interesting project. I love the detachable display idea! There are so many times were I had to take a measurement but there wasnt a good place to put the meter , or the leads werent long enough etc. Im also intrigued by the modular interface. I recently bought an El cheapo component tester from china and your meter could do the same sort of functionality without using two devices. I dont think the data logging is that big of a deal. My home Radio Shack Micronta meter from the 90s has data logging( it came with a floppy disk ). Id like to see the meter measure up to 240vac RMS. Ill have to check out the specs on your modular interface. I can see a lot of possibilities there . Good luck with it . Mike
Cool project. while I'm not personally interested in one I do have some feedback. I feel that for a multi meter not made by a well known company you need to demonstrate how the meter would fail when exposed to over voltage events. I feel that having it only rated for 150v input is going to lead to many instances of over voltage because of standard 240V AC power standard across the world. I would personally like to see at least a 300V rating but a 600V rating would be best. This gets it outside the range of common household and industry voltages respectively. Other than that i personally think its pretty cool and has many nice features.
I really like the project and highly value it being open sec! My first impression was that the controls are quite cumbersome and not really intuitive for everyday use; so adding a rotary switch or making it button controlled with internal relays would definitely make it more user friendly. Apart from this I'd love to see a bench top variant (mostly because that's what I need at the moment 😂)
@ I'd rather just mount the thing on the wall than redesign it atp but for a desktop variant I mean with a larger display, mains psu, potentially more features and/or better accuracy
I just stumbled across this and I love it! Maybe in the future you could make the bottom part of the multimeter compatible with other test & measurement devices as well. There's a lot of potential and I'm here for it!!!
Thanks! Yes, I'm thinking of doing something like a visa compatible interface over serial (the bottom has an RS-422 connection to the top for normal operation), for exactly that kind of thing! Planning of finding/making an adapter from USB to a few RS-422 ports, so you could have a few frontends hooked to a computer for simple logging/control, that sort of thing is even where the name hydra came from.
Were is a good place to offer design review feedback? Should I create issues with GH to allow for tracking of specific items? For example, I run the PCB DRC and it complains that things are not connected. I've wanted to make an open source multi-meter before, but haven't been able to prioritize it. I'm glad to see you making progress on such an effort. I've be happy to offer design review stuff.
Thanks for the offer! I'd definitely appreciate some feedback on the concepts, though there's also definitely some issues I'm aware of in the current revision. For now a comment here is perfect, don't actually know how to track issues in gh yet :) The PCB revision on gh is a slight update from what I made in the prototype, fixing a few bugs in the original design (anything with red box/text in the schematic was updated). One of those updates was removing some ineffective protection on the ohms range, instead of completely unrouting all tracks, I just left some unconnected ones. Not the best design practice, but not worth the time to remove everything while making sure nothing's broken.
@@john_duffy I made a reply but it's not here now. I suspect YT deleted it. I attended to add a cryptic link. Perhaps that got it deleted I'm not sure. I'll try adding to GH issues.
Interesting project. I ran into the same issue a while ago and discovered that a lot of the relatively cheap multimeters use a common all-in-one chip which already has a serial interface. Maybe that will simplify the project BOM, e.g. FS9721_LP3 I like the rocker idea but I would use something without retention, like car window switches. Then you get up-down to move between functions and ranges. Scope creep is a project's worst nightmare, the modular box is a great idea to contain this.
Thanks! yes I did look at getting a multimeter asic, mainly the hy3131 I think, but couldn't seem to source them in small quantities. Do you know any that are easier to get or how to get some?
thanks, right now I've got the adc running at 1.2Ksps, so Nyquist is 600Hz. It's not hardware antialiased though, so could go higher with a firmware tweak. The afe bandwidth is at least well into the 10s of KHz, I was able to test it once with a sig gen and scope about a year ago to make sure it didn't attenuate AC (That the cap and resistors are well matched), but haven't fully characterized it.
What is the accuracy on the voltmeter? I know you have 3 decimal places on the display - but that doesn't mean that the ADC that you have in the voltmeter can really keep up with that accuracy. How do you know how accurate it is?
absolute accuracy isn't well characterized over time or temperature right now, I calibrated it against a pretty new bm235, so I trust it to about half a percent at the same temperature. I'd have to do some more in depth characterization and testing to say anything difinitive, but I think getting that close to a few tenths of a percent of fsr should be possible over a reasonable temperature range, with the current hardware.
Does it measure dc and ac at the same time? Because having to swap between two settings is annoying, and it's easy to think something is dead when it's actually just the opposite!
yes! Switching between settings was exactly one of the things that annoys me (specifically, I had a meter that defaulted to AC and I usually measure DC). Simultaneous AC/DC is already partially implemented, (dual display shown at 2:30 in the video).
What a refreshing thing. Love the standard components. For a truly open source device i think it needs more expansion readiness in all directions with some standard ports. Also - if you are really looking to expand it what works in todays world - not just blueprints (well, maybe in circle of enthusiasts it would work), but a device that is: functional out of the shelf, looks and feels premium and cool (geeks love buttons and leds), has some expansion modules already available (so that ppl can see the vibe of future 3rd party modules). Something like Framework Notebook. In general though the idea is really cool. Get Elon's backing for the production :-) .
Thanks! Yes, I'm looking at making this as expandable as possible, I didn't really mention it in the video but there's a DB9 (DE9) with RS-422 between the frontend and display. Not sure of many other points within a meter that can have standards (adc, radio), though I plan to at least standardize within the meter and and any new versions. Also definitely planning to make more modules, haven't focused much on those yet, mainly just getting the meter working!
Cool project. Why not a large touchscreen instead of a bunch of switches for functions? The user could then customize their display for their most used functionality.
It would likely use more power. Also not really designed to be operated with gloves and doesn't handle water well, at least the capacitive ones. That would be my guess.
That's an interesting idea, I personally like the hardware switches so it's easy to set and durable, but it should be modular enough to replace that with something else!
@johneduffy it's so out of the norm of regular dmms that I think it would be hard to use. You're just used to it since you've probably flipped those switches thousands of time. The other advantage of a touch screen is that control of the meter would still be at your finger tips if you disconnected the screen (which BTW, is an awesome feature).
Love the USB C port. Long time ago I had to do data logging and bought ported meters. They have all died. Now the king of electronics in Australia wants every user to discharge them huge 400V mains capacitors in the ohms range. How many kilojoules can your handle?
Havent to tried to blow one up yet :) only have two examples put together, so want to keep them operational for now, I'll put out an update when I have tested that though
A bit suspicious about wireless display connection performance, especially in industrial environment. what are the characteristics of the radio transmission?
Didn't think to mention in the video, but when attached the display runs through isolated RS-422 - no wireless to be interfered with in most circumstances. When detached and on radio it currently uses an nrf24L01+ (narrow band 2.4GHz, running at 500Kbps for range and reliability), mainly because they're cheap and I had some on hand, the hardware also supports an rfm69hcw though, which is 915MHz and offers excellent reliability and range. Few years ago I was flying drones a lot on a radio that used them and it worked well over a few hundred meters.
Kudos on this project! For those of us outside the USA, an AC voltage range up to ~220-240V would sure be sweet.
Sweet project! I would love to see hz and the data logging is beautiful! It’s something I been wanting to look at making!
I was just wanting a logging multimeter, and started looking into diy!
You made something awesome! Glad you made it real and got past the one more feature trap we often fall into. Still lots of features in here in its current state. Need more of this in the world.
Thanks!
Yeah, absolutely, there's like, a hundred changes and things I still want to do with this :)
And I'll definitely get to every one of them in rev 2 🙃
Finally, someone who shares my passion for homemade devices. Very cool project, I have been making industry field calibration for myself (many revisions), and finding someone like you make me wanting to keep going with the next step, Bluetooth remote control. Very inspiring, thanks. Saluti from Italy
Interesting project. I love the detachable display idea! There are so many times were I had to take a measurement but there wasnt a good place to put the meter , or the leads werent long enough etc.
Im also intrigued by the modular interface. I recently bought an El cheapo component tester from china and your meter could do the same sort of functionality without using two devices.
I dont think the data logging is that big of a deal. My home Radio Shack Micronta meter from the 90s has data logging( it came with a floppy disk ).
Id like to see the meter measure up to 240vac RMS. Ill have to check out the specs on your modular interface. I can see a lot of possibilities there .
Good luck with it .
Mike
Cool project. while I'm not personally interested in one I do have some feedback. I feel that for a multi meter not made by a well known company you need to demonstrate how the meter would fail when exposed to over voltage events. I feel that having it only rated for 150v input is going to lead to many instances of over voltage because of standard 240V AC power standard across the world. I would personally like to see at least a 300V rating but a 600V rating would be best. This gets it outside the range of common household and industry voltages respectively. Other than that i personally think its pretty cool and has many nice features.
I really like the project and highly value it being open sec!
My first impression was that the controls are quite cumbersome and not really intuitive for everyday use; so adding a rotary switch or making it button controlled with internal relays would definitely make it more user friendly.
Apart from this I'd love to see a bench top variant (mostly because that's what I need at the moment 😂)
Just tweak the 3d print to have a desktop stand?
@ I'd rather just mount the thing on the wall than redesign it atp but for a desktop variant I mean with a larger display, mains psu, potentially more features and/or better accuracy
Awesome project! i'm surprised there aren't more open source multimeters with logging like this.
love the open-source multimeter! ✨📲
Thanks! :)
congrats on your progress - I really like it
I just stumbled across this and I love it! Maybe in the future you could make the bottom part of the multimeter compatible with other test & measurement devices as well. There's a lot of potential and I'm here for it!!!
Thanks!
Yes, I'm thinking of doing something like a visa compatible interface over serial (the bottom has an RS-422 connection to the top for normal operation), for exactly that kind of thing!
Planning of finding/making an adapter from USB to a few RS-422 ports, so you could have a few frontends hooked to a computer for simple logging/control, that sort of thing is even where the name hydra came from.
Were is a good place to offer design review feedback? Should I create issues with GH to allow for tracking of specific items? For example, I run the PCB DRC and it complains that things are not connected.
I've wanted to make an open source multi-meter before, but haven't been able to prioritize it. I'm glad to see you making progress on such an effort. I've be happy to offer design review stuff.
Thanks for the offer! I'd definitely appreciate some feedback on the concepts, though there's also definitely some issues I'm aware of in the current revision. For now a comment here is perfect, don't actually know how to track issues in gh yet :)
The PCB revision on gh is a slight update from what I made in the prototype, fixing a few bugs in the original design (anything with red box/text in the schematic was updated). One of those updates was removing some ineffective protection on the ohms range, instead of completely unrouting all tracks, I just left some unconnected ones. Not the best design practice, but not worth the time to remove everything while making sure nothing's broken.
@@john_duffy I made a reply but it's not here now. I suspect YT deleted it. I attended to add a cryptic link. Perhaps that got it deleted I'm not sure. I'll try adding to GH issues.
cool project!
Interesting project. I ran into the same issue a while ago and discovered that a lot of the relatively cheap multimeters use a common all-in-one chip which already has a serial interface. Maybe that will simplify the project BOM, e.g. FS9721_LP3
I like the rocker idea but I would use something without retention, like car window switches. Then you get up-down to move between functions and ranges.
Scope creep is a project's worst nightmare, the modular box is a great idea to contain this.
Thanks!
yes I did look at getting a multimeter asic, mainly the hy3131 I think, but couldn't seem to source them in small quantities. Do you know any that are easier to get or how to get some?
Hello john great work but if you can specify the ac voltage and current bandwidth
thanks, right now I've got the adc running at 1.2Ksps, so Nyquist is 600Hz. It's not hardware antialiased though, so could go higher with a firmware tweak. The afe bandwidth is at least well into the 10s of KHz, I was able to test it once with a sig gen and scope about a year ago to make sure it didn't attenuate AC (That the cap and resistors are well matched), but haven't fully characterized it.
What is the accuracy on the voltmeter? I know you have 3 decimal places on the display - but that doesn't mean that the ADC that you have in the voltmeter can really keep up with that accuracy. How do you know how accurate it is?
absolute accuracy isn't well characterized over time or temperature right now, I calibrated it against a pretty new bm235, so I trust it to about half a percent at the same temperature.
I'd have to do some more in depth characterization and testing to say anything difinitive, but I think getting that close to a few tenths of a percent of fsr should be possible over a reasonable temperature range, with the current hardware.
Does it measure dc and ac at the same time? Because having to swap between two settings is annoying, and it's easy to think something is dead when it's actually just the opposite!
yes! Switching between settings was exactly one of the things that annoys me (specifically, I had a meter that defaulted to AC and I usually measure DC). Simultaneous AC/DC is already partially implemented, (dual display shown at 2:30 in the video).
What a refreshing thing. Love the standard components. For a truly open source device i think it needs more expansion readiness in all directions with some standard ports. Also - if you are really looking to expand it what works in todays world - not just blueprints (well, maybe in circle of enthusiasts it would work), but a device that is: functional out of the shelf, looks and feels premium and cool (geeks love buttons and leds), has some expansion modules already available (so that ppl can see the vibe of future 3rd party modules). Something like Framework Notebook. In general though the idea is really cool. Get Elon's backing for the production :-) .
Thanks! Yes, I'm looking at making this as expandable as possible, I didn't really mention it in the video but there's a DB9 (DE9) with RS-422 between the frontend and display. Not sure of many other points within a meter that can have standards (adc, radio), though I plan to at least standardize within the meter and and any new versions.
Also definitely planning to make more modules, haven't focused much on those yet, mainly just getting the meter working!
If it worked, elon would just steal the glory, like tesla, space x et al.
It needs a usb-c pass-through that's let's it double as a usb voltage and current meter.
Cool project. Why not a large touchscreen instead of a bunch of switches for functions? The user could then customize their display for their most used functionality.
It would likely use more power. Also not really designed to be operated with gloves and doesn't handle water well, at least the capacitive ones. That would be my guess.
That's an interesting idea, I personally like the hardware switches so it's easy to set and durable, but it should be modular enough to replace that with something else!
@johneduffy it's so out of the norm of regular dmms that I think it would be hard to use. You're just used to it since you've probably flipped those switches thousands of time.
The other advantage of a touch screen is that control of the meter would still be at your finger tips if you disconnected the screen (which BTW, is an awesome feature).
@@ligius3 can't remember the last time I have water in the vicinity of my meter, but understood on the durability aspect.
Love the USB C port. Long time ago I had to do data logging and bought ported meters. They have all died. Now the king of electronics in Australia wants every user to discharge them huge 400V mains capacitors in the ohms range. How many kilojoules can your handle?
Havent to tried to blow one up yet :)
only have two examples put together, so want to keep them operational for now, I'll put out an update when I have tested that though
Ya know what depending on the price i would take one of the v2 production runs. Any chance it does auto ranging?
A bit suspicious about wireless display connection performance, especially in industrial environment.
what are the characteristics of the radio transmission?
Didn't think to mention in the video, but when attached the display runs through isolated RS-422 - no wireless to be interfered with in most circumstances.
When detached and on radio it currently uses an nrf24L01+ (narrow band 2.4GHz, running at 500Kbps for range and reliability), mainly because they're cheap and I had some on hand, the hardware also supports an rfm69hcw though, which is 915MHz and offers excellent reliability and range. Few years ago I was flying drones a lot on a radio that used them and it worked well over a few hundred meters.
nice FOSH i call it Free and Open Source hardware
sth similar i was planning for computer peripherals