uSupply Custom LCD

[mariush]

I was also thinking about that ... how many commons / anodes / cathodes such a display would have, how you're gonna multiplex those segments and still have some nice contrast

I was wondering if you couldn't just use some of these existing 8 digit 14 segment things (2$ each for 1000pcs) : https://www.digikey.com/product-detail/en/varitronix/VIM-878-DP-FC-S-LV/153-1113-ND/1118603  (or bigger ones for 3.3$ for 1000pcs

You have 8 digits, and you can write "A" or "V" on the 8th digit and use 6 digits for numbers, and you could also have  CV and CC  using two digits on a 3rd row where you'd also write the watts value.
And you wouldn't even have to connect all the segments for all the digits. If you're only gonna show numbers on first 6 digits, then you'd  have less traces to connect to your microcontroller or what's gonna be used.

[ataradov]

If I'm not mistaken, LCD manufacturers offer COG controller, so you get a nice SPI interface to the display. Not sure how much it adds to the cost.

Driving this thing from am MCU will require 100-pin package, and is probably not going to be cheap.

[EEVblog]

If I'm not mistaken, LCD manufacturers offer COG controller, so you get a nice SPI interface to the display. Not sure how much it adds to the cost.

A quote we got was $2 extra.

Driving this thing from am MCU will require 100-pin package, and is probably not going to be cheap.

30 cent driver chip.

[A Hellene]

Dave, though Nokia 5110 (PCD8544) is a small LCD (1.6", 84x48px), it is a standard 3-pim SPI (MOSI, SCK, nSS), transflective, sun-readable, extremely low power and quite cheaply available display. You can even use two of them...!

If you need more display real estate, there will always be the SPI TFTs, ranging from 1.8" 128x160px (like the one connected to the breadboard, depicted at the top right of the pictures at the link above) to any dimension & resolution you might wish.


-George

[janekm]

Since I've been there/done that on custom LCD manufacturing (new batch of a design the previous supplier wasn't able to delivery at a reasonable cost / lead time), I can add a few points based on my conversations with a LCD factory (the factory was referred to me by my assembly house, as I wasn't quite willing to take the gamble on a "random" supplier):

• It's a really cut-throat market with a lot of competition to drive prices down. The factory owner I spoke to said that some of his competitors use factory labor to get labor costs down.
• The batch size of the factory I used is 5000 units, and their whole process is set up around that, so they totally hate doing anything not divisible by that. They did end up agreeing to do 3000 but really didn't like it.
• Turnaround time is 1 - 1.5 months, and they can't speed it up due to the many process steps.
• They were able to make samples to show that everything is correct (about 20 from what I remember). It seems these don't go through the regular factory process (they did end up looking slightly different and had a bit of a "hand-made" feel about them). Took about 3 weeks from what I recall.
• There are options regarding viewing angle range, contrast ratio etc. I told them I wanted the best visibility they could make and paid them a premium for that. They delivered, the displays are excellent.
• Cost was of course much lower than the previous US-sourced version, but I wasn't concerned with driving it to the bottom, quality was more important.

Dave, happy to give you a reference to the factory we used, though they only speak Chinese...

[Towger]

I would prefer a good generic LCD display, even if it costs more. (Within reason.)  But I can see the point in going custom.  It is cheaper in 'higher' volumes and reduces the lightly hood/time for Chinese closes to appear.

I told them I wanted the best visibility they could make and paid them a premium for that. They delivered, the displays are excellent.[/li][/list]

 

There is nothing worse than a poor display.

The Whales/boffin design is clearer than the original version.

The TimNJ is also good, if the cost of the larger screen is possible.

[julianhigginson]

Open source discussion derailment aside, it's an interesting project to attempt. Lots of cheap power supply options out there now, so I guess you won't be competing on price? Keen to see what the deal is...

Those of you who want the fully hackable/self-sourcable supply made with a more generic LCD should look into the crowd funded one that shipped the other month...

[EEVblog]

Open source discussion derailment aside, it's an interesting project to attempt. Lots of cheap power supply options out there now, so I guess you won't be competing on price? Keen to see what the deal is...

Yep, it's novel, nothing else on the market like it.
It won't be for everyone.

[xani]

Any tease about what exactly it will be ?

Aside from that, I realized that the "first" idea of uSupply (portable battery-powered lab PSU) now could be done by just putting that chinese DPH3205(that one in particular because of buck-boost mode) module in a box with Li-ion battery + charger (altho it would be ~twice as big)

Those of you who want the fully hackable/self-sourcable supply made with a more generic LCD should look into the crowd funded one that shipped the other month...

which one ? I've been looking for something like battery powered power supply that could double as battery/phone charger (which could probably be easily hacked in into existing design if code was available)

[JPortici]

i'll be curious to see the result.
There's been a product i always wanted to convert to a slim form factor, full screen type for display and user interaction.
The display has to be readable from every light condition (to be placed near the steering wheel)
Unfortunately the available choice of OLEDs don't satisfy me, i should use a smartphone type display but they are tricky to get to..

but then i saw of this microchip demo board http://www.microchip.com/promo/pic16f19197-low-power-touch-enabled-lcd-demonstration
and i wondered if a custom LCD was the right solution.. might be.
I've seen some photos of the actual board and the result is astounding, but i can't get my hands on it yet..

The priority of this project is sub-zero so i'll wait and see your experience in custom LCD manufacture

[Corporate666]

Horizontal bargraph for current would be good.

You should also put the EEVBLOG hand logo on there, because you can.

I'd be really interested in finding out about the process of getting a custom display made - tooling costs, unit costs,MOQ, leadtime, design rules etc.

Just as a datapoint, I had a custom LCD made years ago (must have been 15 years back) by Excel Tech (now Excel Display http://www.excel-display.com/).   It was for an automotive tachometer, and had a bar graph arranged in a crescent shape with numbers in the center. 

I don't recall the exact unit price, but it was under $4/ea in quantities of 1000.  There was a $3000 tooling charge.  This included the driver chip (embedded on the edge of the panel) and the module had a flex cable mounted on it.  I don't recall specific design rules, but I originally wanted the module to be round.  Back then, nobody was doing round LCD's, so they suggested flat cuts on the corners... ultimately we ended up with a 10-sided polygon to approximate a circle.  The only issue I ran into that caused a rework of my intended design was 'orphaned' segments in the center of the display that they weren't able to route out.  Lead time was 3-4 weeks from payment received until first unit samples received, and another 3-4 weeks to produce the whole batch.  Could have gotten them faster but I wasn't in a rush.



Dave, definitely interested to hear your experiences!

[The Soulman]

Assuming this isn't going to be a high-power supply, I'd like a current readout in mA and power in mW.
And actual readings bigger than the set voltage and current, a led to indicate for cc/cv would be a nice bonus.

Another "novel" idea is to be able to link multiple of these psu's in some (galvanic separated..) way for simultaneous output on/off. 

[hugo]

What do you think about this one:

[ataradov]

What do you think about this one:

I like this the most out of all versions here.

[julianhigginson]

Those of you who want the fully hackable/self-sourcable supply made with a more generic LCD should look into the crowd funded one that shipped the other month...

which one ? I've been looking for something like battery powered power supply that could double as battery/phone charger (which could probably be easily hacked in into existing design if code was available)

sorry - not battery powered... I didn't realise this was dave's intention for this product.


The fully DIY friendly option for a bench supply is this guy:
https://www.eevblog.com/forum/crowd-funded-projects/preparing-eez-h24005-for-crowdfunding/
all firmware and hardware is open source.

[ebclr]

Small and very cheap LCD

[xani]

Those of you who want the fully hackable/self-sourcable supply made with a more generic LCD should look into the crowd funded one that shipped the other month...

which one ? I've been looking for something like battery powered power supply that could double as battery/phone charger (which could probably be easily hacked in into existing design if code was available)

sorry - not battery powered... I didn't realise this was dave's intention for this product.


The fully DIY friendly option for a bench supply is this guy:
https://www.eevblog.com/forum/crowd-funded-projects/preparing-eez-h24005-for-crowdfunding/
all firmware and hardware is open source.

Ah yes I saw that one. I looked, said "no knob, no service" and ignored it. The last thing I want from my bench supply is some wonky touchscreen

[Kalvin]

Just make sure that the power supplies share common ground / 0V and not that low side current measurement sh*t.

[VEGETA]

Just make sure that the power supplies share common ground / 0V and not that low side current measurement sh*t.

As long as I remember, he uses only one channel and it doesn't have low side current measurement.

Ah yes I saw that one. I looked, said "no knob, no service" and ignored it. The last thing I want from my bench supply is some wonky touchscreen

It is good to have different opinions, but for me the TFT screen is a big plus! 

It makes it modern and gives a lot of options unlike traditional buttons. It inspired me to do my own power supply using a TFT too, but Dave design inspired me about the battery powered feature. I still didn't manage to make a PCB for the prototype.

[free_electron]

make sure to have dual color backlight. if a fault condition occurs i want the display backlight color to switch to red. ( and blink if possible  like 50% on , 100% on , not full on / off)
Also  think about colorblind people.  make sure there is a huge difference between red and green ! too many dual color led's are indiscernable for colorblind people.

[Maxlor]

I'm looking forward to hearing about the design/manufacturing process for custom displays as well!

As a general point that applies to all the screen layouts above: please use a more prominent decimal point. With the very narrow digit spacing, the decimal point becomes hard to see if it's this small (to test: use a reduced resolution image, or squint, or glance at the display for less than a second.) Adding a bit more space between digits so the decimal point is more visually distinct, or increasing it's size, or both would be a good fix.

Also, the display for the set display should be less prominent than the current display, so the user is less likely to mix them up accidentally. Dave's original design accounts for this nicely.

[julianhigginson]

Ah yes I saw that one. I looked, said "no knob, no service" and ignored it. The last thing I want from my bench supply is some wonky touchscreen

1) the last stretch goal added a knob!

2) it's open source... You want to adjust the design with knobs? Add them! :-)

[kalel]

I haven't used any lab power supplies yet, so mine is an inexperienced opinion. I would also prefer knobs, either the multi turn stuff or encoders, versus physical buttons.

I don't know about reliability differences, micro switches have their limits too (if you had to press them all the time to adjust parameters).

As for a pure touchscreen solution - it also sounds difficult to use. I haven't checked the specific product, just generally. If you had one with only touchscreen, could you e.g. decrease current to test the brightness variation in an LED without looking at the screen? You might be able to program a current sweep in a modern supply (I don't know if you can, but I don't see why not), but I would still prefer the knobs.

[fcb]

Forget putting the Watts calculation on the screen - of little actual use unless you have bigger plans for the unit.

Use the space to put a couple of symbols, like battery state for the LiIon and maybe your logo (when it boots up).

[NivagSwerdna]

My ideal uSupply would allow me to charge my Li Ion cells.... and on completion it would show me how many mAhr it had pumped in to them.

So it would have "hr" as a segment and possibly also "Complete" or "Done"

Possibly also time in MMM:SS as it charges

Just sayin'