What is the status here now?

Are you going to make a PCB, which is populated with a MCU, LCD, power regulation and such?

Are you able to design it yourself?

 

Detection voltage is from 2.5v - a bit too high for your less than 1v.

i missed that...lol
i checked on the same site, similar kinds are not available for <1V

 

What is the status here now?

Are you going to make a PCB, which is populated with a MCU, LCD, power regulation and such?

Are you able to design it yourself?

1. i want to populate it with as less resource (ICs) as possible (dont mind if MCU is necessery but should fit with point 2)
2. i have area constrants. want the whole thing <5x5 cm2
3. i am somewhat able to design circuit, PCB layout and soldering small ICs

 

OK, then you have to find an MCU, a LCD, a way to regulate power...

I'd choose:
PIC 16F688 or PICAXE14M2 (These are not pin compatible)
8x1 LCD
2 100uF eletrolytic caps
3 0,1 ceramic caps
LM78L05

And some wiring and "probes".

This is from the top of my head, and not tested...

 

no, less than 1 v.

i am looking for a very small solution. LCD (3 digit is enough) and MCU both must be of small scale.

well...for the passive 3-digit LCDs you'd need a 16f59 available as TQFP44 and price point around $1 and super easy to program in C language.

The multiplexed kinds arent as easy to drive and arent really available on hobbyist/DIY market.

I made a carrier board for 2x 3 digit LCDs with 2x 16f59 some while ago, its not totally small but the controllers sit under the LCDs, and in theory, its possible to cut off one half for size reasons.

Driving is very simple, you have to drive the substrate* with a square wave, then if you want the segment off, drive them in phase otherwise inverse polarity.

This can be done in software easily even at low MCU frequency.

*also called backplane

If interested I have quite a few of these PCBs around + recently I bought a fresh batch 16f59. Only needs: Inductor for clocking, small 1uF capacitor, 1 resistor.
PICKIT2 or PICKIT3 + MPLABX software (free)

I even have one of the original LCDs but they werent cheap so the PCB never went on sale.

2

Actually I know a distributor which sells 3-digit small LCD modules with integrated driver IC, 8 pin interface, you could use almost any small controller.
Its a custom module however so Digikey etc. wont have these. And once sold out thats the end of it.

Might be what you are looking for.

If you look for a quartz watch size display, these arent sold on the open market or at least I and my sales contacts havent yet been able to find these.

They all use zebra ribbon connectors and these also arent sold anywhere on the open market at least not to my knowledge. And multiplexed too.

 

no, less than 1 v.

What is the maximum voltage you want to measure?

 

and you could use MCP1640 to stepup voltage however I dont recommend it particulary for LCD.

The 16F5x can work with very little currents when driven with low frequency, and unless you go into the depths of the MCP1640 variants you'll find it difficult to archieve less than some 100uA quitescent current, even more close to one mA.

So using 2x NiMH is ideal since it can work with 2V easily, and these cells will maintain 2.4 volts until the very end of the charge.

Duracell gave the best results, some others dropped out even after only a small number of cycles.

I used a 470uH coil on the PCBs but never really measured frequency or currents.
A 32 KHz quartz crystal is a bit on the edge if you want to use a software serial port, and what you can do with 2K standalone is limited, well I did I2c interface for RTC chip but couldnt add more code at some point.

 

......................

2

Actually I know a distributor which sells 3-digit small LCD modules with integrated driver IC, 8 pin interface, you could use almost any small controller.
Its a custom module however so Digikey etc. wont have these. And once sold out thats the end of it.

Might be what you are looking for.

this sounds good...can you give me a bit more detail. How much would this cost??

 

i missed that...lol
i checked on the same site, similar kinds are not available for <1V

they do have a unit that does 0-99.9v in 0.1v steps depends what you are trying to measure I guess.

 

not much however overseas shipping directly to USA a fortune they dont do flat envelopes.

I could buy some with next order, shipping costs to Europe are flat no matter the weight when ordering from this distributor.

Resell for less than $2, probably 1.58 or so

 

Hi, is it possible to interface a LCD with a circuit output (analog) without a MCU. i mean i dont want to program a MCU, rather want a circuitry for interfacing (if any). any suggessions would be apprecited

Somewhere I vaguely remember seeing a chip that does this - probably a pre-programmed PIC or something stocked as an off the shelf item.

Sounds like the sort of thing Picaxe might do.

 

Sounds like the sort of thing Picaxe might do.

See post #24.

 

not much however overseas shipping directly to USA a fortune they dont do flat envelopes.

I could buy some with next order, shipping costs to Europe are flat no matter the weight when ordering from this distributor.

Resell for less than $2, probably 1.58 or so

it looks cool and cheaper but i dont see any driver IC here. so its just the LCD??

 

OK, then you have to find an MCU, a LCD, a way to regulate power...

I'd choose:
PIC 16F688 or PICAXE14M2 (These are not pin compatible)
8x1 LCD
2 100uF eletrolytic caps
3 0,1 ceramic caps
LM78L05

And some wiring and "probes".

This is from the top of my head, and not tested...

this is a very simple solution indeed. but the problem is, there is no PICAXE distributor around.
if i buy from online store the shipping cost would be 20 times the IC itself.

 

but the problem is, there is no PICAXE distributor around

Where are you?

 

Where are you?

Japan

 

Japan

Move to China - that's where Japan has everything made now!

 

it looks cool and cheaper but i dont see any driver IC here. so its just the LCD??

it has a driver IC actually visible on the picture.

I can add some of these to next order I always place larger orders to offset the shipping costs. Takes a little less than 10 days and I plan to order again beginning next month.

 

Move to China - that's where Japan has everything made now!

I wouldnt call this reply any useful besides who, economically, can just "move" best of all, by the advice from a forum reply?