Programmable display voltmeter

[greenalien]

I've just found out about these panel meters - http://docs-europe.origin.electrocom...6b80e36099.pdf

available from http://uk.rs-online.com/web/search/s...duct&R=7048138

The price seems amazingly low for something so versatile. Looks to have a lot of potential uses, particularly as the basis for a low-cost laser power meter, due to their programmable gain input amplifiers. I'll be very interested to see what the forum's electronics experts can come up with as a design - in the mean time, I'm going to order one to play with!

[flecom]

holy crap thats pretty awesome

order one and report back!

hook it up to a thermal head and you have a nicest/cheapest laser power meter i have ever seen lol

[danielbriggs]

I've had some of these for several months now (even before they were released! )
I did some work with them a while back as they were getting ready for production.

The current capability it offers is ok.
But the hardware is capable of oh so much more...!
Later firmware updates should bring in the extra features they list on the hardare spec sheet, but which are not yet implemented.

I'll stick it in a box to take to Surfleet should anyone want to have a look

I've programmed one as a display for my Coherent thermopile power meter, and also done one for a lscp's tube current meter.

You can add in your own "splash screens" which is nice...

Cheers,
Dan

[300EVIL]

Sweet! I want one!

[greenalien]

I've programmed one as a display for my Coherent thermopile power meter

That's exactly the use I had in mind - am I right in thinking that all you need is a thermopile and the meter? You don't get much voltage from a thermopile, so I guess this is where the programmable range and sensitivity come in handy. Unfortunately, I can't make Surfleet as I'd be really interested in seeing this in use - how about a few piccies?

[danielbriggs]

You would need an amplifier to boost the voltage straight from the thermopile.
The meter is only good for a resolution of ~0.01V (which I think is ~1W from my un-amped Coherent thermo-head! )

You would *not* need any additional amps if you're using something like those 60W Ophir heads floating around on eBay, as they have an built in amplifier.
http://cgi.ebay.co.uk/Ophir-OEM-Lase...#ht_1209wt_709

Also to note; while great little product, the touchscreen, SPI + I2C buses and 2nd voltage input are physically there, they are not useable at all with their current shipping firmware.
Like I said great product hardware-wise with a load of potential; but the firmware + software implementation isn't quite there that would make it 10x better.

Photo's are little awkward this moment. Give me a couple of weeks; house move at the mo, and things are all over the place or packed away...

Let me know if you need any other information.

Regards,
Dan

[greenalien]

the touchscreen, SPI + I2C buses and 2nd voltage input are physically there, they are not useable at all with their current shipping firmware.

It's a shame that these functions aren't available yet - also, a larger (2.8" rather than 2.4") model is due imminently, and only costs £10 more, so perhaps I'll wait and watch for a while.

Do you have a suitable amplifier circuit for a thermo head? I have a 20W Ophir device that doesn't have a built-in amplifier.

[danielbriggs]

Do you have a suitable amplifier circuit for a thermo head? I have a 20W Ophir device that doesn't have a built-in amplifier.

For the thermopile I robbbed one from part of a board that had something suitable on it already. So I don't have schematics for it unfortunately

If you want to have a play with one I could loan you mine for a short period in a couple of weeks when things settle?

Regards,
Dan

[greenalien]

Dan - that's a very generous offer. I think I'm going to adopt a 'watch and wait' approach at present but will probably buy one of the larger displays once they are available. In the meantime, I'm still looking for a suitable voltage amplifier circuit...needs to have a gain of around 1000, so 1mV input gives 1v output...I'm sure I could sort something out with an op-amp and a couple of resistors, but is there a better, tried and tested way...anyone...?

[loopee]

I bought two of these about a month ago

Actually, I bought one, broke it, had to send it back and in the process bought a second one. BTW I did the breaking and it was not the fault of the meter!

I discovered that it can be configured via a serial interface, something that's not really supported, but I was working out the commands and discovered the one to delete everything (no warnings on that one) Bonus is I got the firmware upgraded to the latest!
If anyone wants the commands PM me (but I didn't tell you)

Very cool device for there cost

One issue I have discovered is you can't configure the decimal point, it's set at two places therefore making 100 mW type measurements hard when you need it to do Watts as well

Photo's





Edit: BTW you can buy these direct online from Lascar (http://www.lascar.co.uk) should be cheaper than RS!

Troy