Panel Meter V1 product-project

[sotoszorbas]

Hi, all

I'm new to this forum although  not new to EEVBLOG nor electronics.. The reason I open this topic is for the people to tell me their honest opinion about a project I've made and possibly how I can make it better. I won't lie to you part of me wants you to visit my page and see what I've made. Another BIGGER part of me is looking for people's opinion into something Dave inpired me to do. What's that? Turning a project into a product !    Check it out, get schematics,  build one,  whatever you like



https://www.tindie.com/products/sotos/-panel-meter-v1/

[danadak]

One of the problems with a project like this is visible display in all environmental
conditions. eg. direct sun, and distance to display. Of course this generally makes
power consumption go up in order to get adequate contrast.

A way around this is to use the sun as a contrast power source for the display, a reflective
or transflective technology uses sun to create the contrast while minimizing power impact.

One technology that is easy to see across a brightly lit room is VFD, but its power hungry
when design has to develop the light.

7 seg displays are very limited in this environment. Makes one wonder if you did this in
high power LED array matrix.......

Another issue is measuring V with a differential approach. Most panel meters single ended,
so in a CM environment accuracy suffers.


Regards, Dana.

[coppice]

Small panel meters, other than those built to industrial standards, are extremely cheap these days. Its hard to see how you could make money from basic measurements, like voltage or current.

[DTJ]

That's a nice enclosure. Is that an off the shelf item?

[sotoszorbas]

One of the problems with a project like this is visible display in all environmental
conditions. eg. direct sun, and distance to display. Of course this generally makes
power consumption go up in order to get adequate contrast.

A way around this is to use the sun as a contrast power source for the display, a reflective
or transflective technology uses sun to create the contrast while minimizing power impact.

One technology that is easy to see across a brightly lit room is VFD, but its power hungry
when design has to develop the light.

7 seg displays are very limited in this environment. Makes one wonder if you did this in
high power LED array matrix.......

Another issue is measuring V with a differential approach. Most panel meters single ended,
so in a CM environment accuracy suffers.


Regards, Dana.

Standars 0.39" and 0.28" displays were used (~60mA consumption). These displays as you mentioned are crapy  things and your eyes, I thing, get hurt I you stared to them struggling to get a reading. The thing is , I was myself taken by surpise, is that the solution here has everything to do with the filter. I was excited to see the the panels under natural sunlight and my lab's 200W fluorescent lighting  was better than any other screen I tried before. (lcds don't stand a chance)

It's all about the optic  filter !!

The PM uses a high side current sensor and the feeds its output to the external ADC. So it make differential measurements when measuring current.

[sotoszorbas]

That's a nice enclosure. Is that an off the shelf item?

The encloseure was the hardest thing to  find (especially with tha filter). I ordered the directly from factory...

[sotoszorbas]

Small panel meters, other than those built to industrial standards, are extremely cheap these days. Its hard to see how you could make money from basic measurements, like voltage or current.

Yes I do get your point. Me personally I would not chose this PM to just read volts and amps ! It's too expensive  ! The time I would buy it whould be If I was making a  serious project (not a breadboard crap) were I needed the accurate measurements taken to be tranfered to other hardware/microcontroller (you can't do these thing with a 15 buck 3 1/2 digit PM.), data logging, one extra microcontroller (the one built in)  to take care various stuff and the list goes on my Tindie page.

[sotoszorbas]

OH S....t!

I was thinking again of pricing and I could not find a way to cut down on price. Then for a brief moment I realized that in my BOM list a had goofed up 1 component price making the hole product more expensive without a reason!!!!!!!!! After rechecking everything I updated my prices.

    I guess its better to admit, I f** that up , anyway....

[Buriedcode]

The cheap filters for segment displays tend to just be those for the colour of the display, but the better ones are circular Polarisers.  That means the light entering form the front, gets blocked on its way out when it reflects off of the display, where-as the light coming from the display is circularly polarised (50% loss).  They are not perfect, and circular polarisers are dependent on wavelength, but do a great job of enhancing contrast.

As mentioned, the other option would be a reflective, or transflective LCD.  The downside with those is the driving signals, but the upside is reduce current consumption when the backlight isn't used (a couple of mA).

As a product it might fit a certain kind of niche, but there are plenty of off-the-shelf panel meters with adjustable ranges, and often if someone is putting together a panel, they are generally savy enough to design it all themselves.

[sotoszorbas]

For anyone intrested, I updated the Tindie page and went OSHW  . At "Documentation" anyone can download schematic, pcb and documentation files. Example code is available too.

Build it, change it, buy it, do nothing is up to you.


Thank you all for spending time into my project !!!!   

[sotoszorbas]

Here is Dave's presentation of my creation:



Visit my Indigogo campaign I started out:

https://igg.me/at/panel-meter-v1

or visit my regulal Tindie Store:

https://www.tindie.com/products/sotos/panel-meter-v1/


Have a great weekend everyone !!! 

[prasimix]

Sotos, I'll repeat here a question asked on hackaday.io pages: where is a link to repository where one could see your OSHW design?

[sotoszorbas]

Prasimix,

I've already replied to you in hackaday.. visit my Tindie page linked here, and you will find the files at the right side of the page.   

[prasimix]

Great, thanks. I missed Tindie, and it seems link if for some reason broken. Anyway I found it on your IGG campaign. Wish you luck 

[ebclr]

Enclosure 0.18 USD

https://world.taobao.com/item/21536536122.htm?fromSite=main&spm=2014.21345292.0.0

[sotoszorbas]

The cost of the enclosures I bought, was about 0.75 euro/pcs + shipping+customs => 1.7euro/pcs
The purchase was made directly from the factory for 62 pcs total.
That's the enclosure's page:

http://www.china-mould.com/en_Productinfo.asp?ClassCode=a1.bn&ProductID=771

A smaller order whould be possible, but not worth while since shipping costs are quite high, considering the price/pcs....