finding good analog panel meters

[djacobow]

I have a project in mind where I want the display to be one or two large analog panel meters. They'll be driven by a pwm from a uC.

Anybody have advice on how to source these components?

I see some handsome NOS Simpson analog DC milliammeters on Ebay, but they are in the $20+ range, going up to some pretty high numbers.

Legit supplies of new meters seem to be asking on the order of $90+.

I did find some decent (but not fantastic) looking meters on Aliexpress, but mostly in inappropriate ranges or set up as voltmeters. ex: https://www.aliexpress.com/item/DC-0-5A-Mini-Pocket-Amperimetro-Analogico-Analog-Ammeter-Panel-meter-Tester-amperemeter-For-Experiment-Home/32601040112.html


My technical question is am I right to presume that if I buy a meter set up as a voltmeter that it will be easy and obvious to remove an input resistor to make it work like a naked ammeter? Similarly, if I buy a high current ammeter, will there be an easy to remove shunt? Or, are these sorts of things integrated into the inner-workings somehow such that you are basically stuck with the meter as configured?

Related to that, does anybody sell the naked movement, perhaps with a blank card, along with a datasheet that tells the movement's actual specs?

[rstofer]

By the nature of the movement, all analog panel meters measure current.  Sometimes there will be a notation on the scale which will give move information - like full scale current even if it is a voltmeter.  It's even better if they tell you the internal resistance.

Good meters are going to be sensitive - maybe 100 uA full scale or perhaps somewhat less sensitive at 1 mA full scale.  You can pick your series resistor to drive the meter appropriately.

The October 2017 edition of Nuts and Volts Magazine has a nice article on the Care and Feeding of Analog Meters.   There is information on determining the full scale current as well as the internal resistance.  Clearly, when measuring voltage, the internal resistance plus the external resistor are used to arrive at full scale voltage.

About a year or so back, I bought a brand new -1 0 +1 mA large scale Simpson meter.  I don't recall where I bought it but it was through one of the large distributors so the price was high.

[djacobow]

Yeah. I'm old enough that learning how to use convert a meter movement into the measuring device you want (ac or dc voltmeter, or ac or dc ammeter for higher currents) was actually part of my EE curriculum. I understand the theory just fine. But the meters for sale are generally not naked movements, they already have series resistors / diodes / shunt resistors already in place to make them work like voltmeters, ac instruments, or high current ammeters, respectively.

My question was specifically about how accessible those extra bits are so that I can remove them and gain access to the unadulterated movement without having to get into the guts of the meter.

[Neomys Sapiens]

http://panelmeters.weschler.com/category/all-categories-product-by-type-analog-panel

http://larsonmetercraft.com/

http://www.jewellinstruments.com/meters-and-avionics/panel-meters/analog-meters-product-list/#Jewell

http://www.g-mw.de/

http://www.deuta.de/deuta-anzeiger-01.pdfx

http://fariabeede.com/2-pages/home.php

http://www.hoytmeter.com/index.php

http://www.prefag.com/desktopdefault.aspx/tabid-215/

http://www.esterline.com/advancedsensors/Products/AnalogueProducts.aspx

[edavid]

My technical question is am I right to presume that if I buy a meter set up as a voltmeter that it will be easy and obvious to remove an input resistor to make it work like a naked ammeter? Similarly, if I buy a high current ammeter, will there be an easy to remove shunt?

Usually that is the case, but I haven't taken apart a Chinese panel meter to confirm it.

You could get the 2V scale version, and then you could make it work even if you couldn't remove the resistor:

https://www.aliexpress.com/af/85c1-meter.html?site=glo&groupsort=1&SortType=price_asc&g=y&SearchText=85c1+meter

Or how about some 1mA meters:

https://www.aliexpress.com/af/1ma-analog-meter.html?SearchText=1ma+analog+meter

[djacobow]

Thanks, Neomys. That's a great list.

[djacobow]

That's a good idea, edavid. I should be able to drive either easily from a micro, even without a buffer.

[Old Don]

You can remove face plate from a meter in most cases and flip over, paint and relabel as you see fit.

Also try All Electronics:  https://www.allelectronics.com/category/385/meters-panel/1.html

[Neomys Sapiens]

One was missing:

https://www.bowenfr.com/Capteurs-et-Mesure-20-fr.html

[ebclr]

Will this one fit your needs ?

[floobydust]

Consider using stepper-motors for gauges, like car dashboards do. I.e Switec X27.168
Lot's of Arduino code etc. out there, easy H/W

[timb]

That's a good idea, edavid. I should be able to drive either easily from a micro, even without a buffer.

I’ve had good luck driving 500uA and 1mA meters directly from the Cypress PSoC line of MCUs. They have built in IDACs, so can basically hook them straight up. The IDACs have three current ranges, 512uA, 1.024mA and 4.096mA, so in the first two ranges the full scale is equal to the meter’s full scale range.

Here’s a 500uA meter being driven with the PSoC5LP’s WaveDAC8 in current mode. (The actual movement is super smooth, obviously the GIF doesn’t reflect that.)