uSupply Custom LCD

[VEGETA]

If it is custom, how can you drive it via MCU? I mean, will it be the same like other LCDs?

LCD controller chip. This was already mentioned in this thread.

I mean, its segments are different than traditional 16x2 LCDs. Can it work with controller chips used with other LCDs? if so, then something like Arduino library is capable of using it but it needs some tweaking to modify segments since they are different than traditional LCDs.

[ataradov]

I mean, its segments are different than traditional 16x2 LCDs.

16x2 LCDs use LCD controllers specifically designed to control displays like that. There are other controllers that just control the matrix of arbitrary segments (in this case 8 x 32 = 256 segments max).

Can it work with controller chips used with other LCDs?

It is a bare glass, it can be used with any controller capable of driving enough segments (and that specific arrangement of segments).

if so, then something like Arduino library is capable of using it but it needs some tweaking to modify segments since they are different than traditional LCDs.

That's Arduino problems.

[mikeselectricstuff]

No room/segments for a bargraph? A current bargraph would be a handy feature on a PSU.

[NivagSwerdna]

Other than a linear display aka bargraph the latest version looks great.

[Dubbie]

Just curious what would a bar graph be good for? Faster response so you can see current bouncing up and down?

[ataradov]

Just curious what would a bar graph be good for? Faster response so you can see current bouncing up and down?

It would be useful to see how close you are to a set current before CC kicks in.

[mikeselectricstuff]

Just curious what would a bar graph be good for? Faster response so you can see current bouncing up and down?

Yes.
This is hard to see on a digital display, even one that updates quickly.

[stmdude]

Just curious what would a bar graph be good for? Faster response so you can see current bouncing up and down?

Yes.
This is hard to see on a digital display, even one that updates quickly.

Ooohh.. Old-school VU-meter "peak-hold" functionality would be awesome for getting an idea of inrush-currents and peaks.

[xani]

New version looks nice, altho knowing what uSupply will actually do aside from current limit + power/charge calculation would be helpful

Ooohh.. Old-school VU-meter "peak-hold" functionality would be awesome for getting an idea of inrush-currents and peaks.

Let the scope creep begin At that point probably graphical LCD would make more sense and then you can just graph it, or just... display as text ("Ipp/Vpp in last minute", Iavg, Ip-p etc.)... and if you need those you might want to export it via serial or save somewhere and are probably few $ more in parts count and outside scope of the project 

[The Soulman]

Latest version:

Couldn't move the lock and add a m above the V and A?
I'd personally find 1 mA more pleasant to look at than 0.001 A,
and if hardware allows you could go down to 0,1 mA or even lower, much more practical for dealing with small electronics projects.

[ataradov]

I'd personally find 1 mA more pleasant to look at than 0.001 A,

"1 mA" and "0.001 A" have very different meaning. I doubt this thing will have multimeter-quality frontend, so its accuracy at low currents is not going to be super high.

and if hardware allows you could go down to 0,1 mA or even lower, much more practical for dealing with small electronics projects.

Use multimeters.

Stop with the feature creep. That's how 99% community projects die.

[The Soulman]

I'd personally find 1 mA more pleasant to look at than 0.001 A,

"1 mA" and "0.001 A" have very different meaning. I doubt this thing will have multimeter-quality frontend, so its accuracy at low currents is not going to be super high.

(000)1 mA is still the same as 0,001 A and IMHO more practical for smaller electronics.

and if hardware allows you could go down to 0,1 mA or even lower, much more practical for dealing with small electronics projects.

Use multimeters.

The whole point of this uSupply is it's small size and practicality, the need of adding multimers to get some half accurate readings almost defeats having a read-out on the display at all and would take away a large selling point.

Stop with the feature creep. That's how 99% community projects die.

I don't think it is a community project, Dave posted a couple of drawings for us to shoot at, in the end it is going to be a commercial product.

[ataradov]

The whole point of this uSupply is it's small size and practicality, the need of adding multimers to get some half accurate readings almost defeats having a read-out on the display at all and would take away a large selling point.

And you can estimate and order of magnitude just fine. If you need an actual measurement - use measurement tools. All in one never works well.

I don't think it is a community project

Me neither, but this demand for random features is very indicative of community projects. And in this case only one aspect was exposed, and people suggest the device should do all that things they want.

[mikeselectricstuff]

Maybe an auto/manual range indicator.
Perhaps also remote/comms indicator if there is an interface (though could maybe use (flashing) padlock.

[mariush]

Also , if this is a product that may be optionally working from battery only (disconnected from mains), maybe it would make sense to have a low battery voltage indicator

[KE5FX]

https://youtu.be/WoRJOCdNahc?t=17m38s

'Nuff said. 

(I can't figure out how to embed the video, but the link goes to a relevant spot in the John Kenny interview.)

[ataradov]

'Nuff said. 

If this thing had VFD, he would have justified that as well. That's called marketing.

[KE5FX]

'Nuff said. 

If this thing had VFD, he would have justified that as well. That's called marketing.

In 2010 you might be able to argue the point one way or the other.  In 2017, no.

It only makes sense to use an antique fixed-segment LCD if you know you will not face any market competition.  It's a hobby project in that case, not a commercial one.

[mikeselectricstuff]

It only makes sense to use an antique fixed-segment LCD if you know you will not face any market competition.  It's a hobby project in that case, not a commercial one.

..or you care about power consumption.
Or long-term security of supply
Or cost.
Or sunlight readability.

[KE5FX]

It only makes sense to use an antique fixed-segment LCD if you know you will not face any market competition.  It's a hobby project in that case, not a commercial one.

..or you care about power consumption.
Or long-term security of supply
Or cost.
Or sunlight readability.

I'm skeptical about the middle two, certainly.  When you design something with a weird part -- and a custom LCD is certainly a "weird part" -- you are at the mercy of your supplier, specifically future changes to their minimums and lead times.  Cost-wise, the best way to attack that problem is just to assume that you'll have to hit alibaba.com every so often to find the next big load of surplus panels that someone's dumping on the market. 

Power consumption... well, it's a power supply, isn't it?

Sunlight readability was one of the many Achilles' heels that was going to sink the iPhone, as I recall.

(Edit: yes, I know, the decision's made and no longer open to debate, which is fine.  But I couldn't resist posting the link to the Kenny interview, since Dave seemed so receptive to his point at the time.)

[NivagSwerdna]

It only makes sense to use an antique fixed-segment LCD if you know you will not face any market competition.  It's a hobby project in that case, not a commercial one.

Actually this is an EEVBlog project.  The revenue from the video discussing the making of the custom LCD will probably cover the cost. I'm looking forward to seeing the video.

[jbb]

I think that’s a good start.

Custom character LCDs really are great for visibility and clarity, especially under variable lighting conditions. Plus they use a lot less power (which may or may not be relevant here.)

On the multi-colour backlight front, do remember that there are colourblind people out there.

Assuming you’re not running into trouble with segment count, I would suggest the following (most useful to least IMHO):
- Error
- CP (constant power)
- Over currrnt trip
- Over voltage trip
- Remote
- Ohm, kOhm indicators (in case someone wants to make a uLoad)

As others have suggested, a bar graph could be nice but isn’t critical.

Edit: removed stuff that was already done (I was late to party...)

[KE5FX]

As others have suggested, a bar graph could be nice but isn’t critical.

I really like the bar graph idea.    I always want to know how close I am to my preset current limit, but none of my bench supplies presents that information in an easy-to-read form.

[max_torque]

Nice Dave.

Can you fix the kerning on the mJ and Wh. It will help legibility and look more polished.

I didn't even notice the kerning problem, it happened in the conversion from vector artwork to png. Weird.

That already looks a lot more mature than the previous version. I like the increased legibility of the things in solid blocks.

I do notice that the MIN/MAX aren't sized the same on the volt side of things. That should of course be a minor fix.

Yeah that was fixed, forgot to update the section with the MIN/MAX template.

Thanks everyone!

From a intuition point, i'd have MAX above MIN (rather than the otherway around) on the display.  In fact, i might have:

MAX
CC
MIN

to make it even more intuitive

[ataradov]

From a intuition point, i'd have MAX above MIN (rather than the otherway around) on the display.  In fact, i might have:

MIN/MAX segments will never be seen at the same time. What difference does it make?