Metrix MTX3282 Graphical Digital Multimeter

[cyteen]

Nice review of this multimeter, taught me a few things I'd missed from the manual.

Isn't it about time for a look inside? I have the misfortune to have the MTX3281 which has no external power supply so finding out what to add would be a great service. Additionally, since bluetooth RS232 modules can be had from ebay for under $8 and this was an option on the whole range, it would be nice to see how easily it could be retrofitted.

PS. The trick to opening the case is in the middle section of the hinge.

Cheers,

Mark.

[cyteen]

Just caught up with your math function/tear-down video.

The pictures in the attachment show the opening procedure on my MX3281 and some extras show the top of pcb once the shield is removed.

[Kiriakos GR]

Hi Mark.

Thanks for the dmm disassemble tips, but about the BT addition I did lost you there.

Are you assuming that you can use an 8$ USB BT module at your computer?
Or that you install the BT module in the meter it self ?

Either way those BT modules they have a unique ID which requires a specific driver file so to operate.
The cheap BT modules are fakes with limited ability to work properly.

[cyteen]

I was hoping that there would be space and support on the meter pcb for powering a bluetooth module (cheap or more legitimate) since all the Metrix MTX328X have bluetooth as an option.

I haven't played very much with the BT modules, what kind of limitations can I expect? All I was aiming for was two way RS232 in another project and one way in this multimeter.

M.

 

[MJLorton]

Nice review of this multimeter, taught me a few things I'd missed from the manual.

Isn't it about time for a look inside? I have the misfortune to have the MTX3281 which has no external power supply so finding out what to add would be a great service. Additionally, since bluetooth RS232 modules can be had from ebay for under $8 and this was an option on the whole range, it would be nice to see how easily it could be retrofitted.

PS. The trick to opening the case is in the middle section of the hinge.

Cheers,

Mark.

Hi Mark,

Thanks for the post and the info on how to open it. You are the only other person I know that has this meter....are you happy with it beside not having the BT and external power?

I will add this as a project to attempt in the future.

Cheers,
Martin.

[cyteen]

Its a nice thing and a very good example of industrial design. After you've used it on the bench you have to laugh at the reviews that claim that the tilting bail is  'a good one' rather than just a bad idea in the first place.

I think you covered all the plus points in your review and the negatives seem very minor (once its booted).

I've a cheapish meter on the way that I'll to add BT to as a learning exercise and then I'll look at adding it to the metrix.

If you'd like any closeups of the pcb without having to open yours up let me know.

[iloveelectronics]

Either way those BT modules they have a unique ID which requires a specific driver file so to operate.
The cheap BT modules are fakes with limited ability to work properly.

Do you mind expanding a bit on the "limited ability to work properly" part? I'm working on another project using Arduino and a cheap BT module and I did have some issue connecting to it but was eventually solved using a different connection method. The module works smoothly otherwise with all other COM port communication software I've tried.

[Kiriakos GR]

I haven't played very much with the BT modules, what kind of limitations can I expect? All I was aiming for was two way RS232 in another project and one way in this multimeter.

M.

Other than the actual installation ( connection with the PCB), I do not think that your dmm haves the necessary firmware so to support it.   

[cyteen]

It is present in the firmware as an option, switchable from IR.

[Kiriakos GR]

In this case you have to find the identical module which this firmware supports.

I got before some years one ACER laptop which was having BT support but the specific model was not shipped with the BT module in it.
I did find the exact PCB / BT module, which was having the same IC as the ACER spare-part, at 50% less pricing, but 3 times more expensive than the cheap generic ones which does not work out of the box. 

It would make more sense if you contact France about finding out what Metrix suggests as solution.
On the dmm PCB there is one connectors set, possibly is to hook up the BT module. ( a wild guess)
If this is the case, then they could send you the right one, so to make your upgrade by your self. 
 

[Haku]

hi, digging up an old thread I know but I only just saw the video recently.

I have a Metrix MTX3282 and a MTX3283 bluetooth, I'm not rich I just got lucky on a couple of eBay auctions for about £75 each, the only downside was that neither came with any accessories.

They're the best multimeters I will probably ever own, their last calibrations were over 7 years ago but I doubt it makes any difference to me with my hobby electronics tinkering, and I love that it can use rechargeable AA's not the 9v's that so many use, and that I can measure v+A to see watts. Using both multimeters measuring V+A I can see the efficiency of voltage regulators.

When I got the MTX3282 I told a friend the seller had listed another and they won bidding on it for about the same price too, once they received it they contacted the makers and bought the serial cable and a couple of power supplies so I could have one. I didn't have enough spare cash to get my own serial cable (it was almost as much as the multimeter!) and tried to work out how to make my own using a phototransistor and LED from a (really) old ball mouse, the mutlimeter did make an initial response when the software tried to connect but it didn't go any further.

Do you have any ideas how I could make my own serial cable? What components etc. as it would be nice to use the logging functions of them beyond awkwardly looking at graphs on the little screen.

As for the bluetooth enabled one, I can get my laptop with built in bluetooth to pair with it but couldn't get any further than that, issues with the software not being able to connect to the virtual serial port or something, I don't know.

[Mr Eastwood]

and tried to work out how to make my own using a phototransistor and LED from a (really) old ball mouse, the mutlimeter did make an initial response when the software tried to connect but it didn't go any further.
Do you have any ideas how I could make my own serial cable? What components etc.

Maybe you could pickup up a cheap UNI-T multimeter optical rs232 cable and try and make that fit / or use parts ?

After a little bit bit googling I found this circuit which might help..



The site URL the image was taken from is here..
http://www.designelectronics.com.au/DesignElectronics_UT61E-APO.htm

[Haku]

jucole, thanks for the reply and finding the diagram, I'll give it a go and if I still can't get anywhere I'll get a cheap UNI-T optical serial cable, I saw some for $10 shipped from China.