small LCD displays

The higher you go with mux ratio the more you have to worry about low contrast and contrast shifts with temperature. I think x3 or x4 is pretty trouble-free.

Best regards, Spehro Pefhany

Understood. Still, a small price on a 4-MUX LCD.

The customer is happy with x4, even for outdoor direct sun-light viewing. But we might run out of display elements. We might need to group the "clock features" into a separate common. Namely, the first digit as 0 or 1, AM/PM and colon. Since they are not needed for other functions, we can hardwire the switch between commons.

We are still working out the design. When it's ready, everybody here can get a free sample.

Linnix,

Can you tell us what the application is for your LCD there? (I believe you said you've already sold a bunch of the older design...)

---Joel

The device has an AVR (Atmega169) with a 12x4 LCD and four buttons. The uC interface with a custom sensor and display data on the LCD. The buttons can do some simple config and setup. It is approximately

However, we believe that if we put it in the form of a watch (1 sq. in.), it will have better market exposure. Furthermore, if we reuse the LCD in other projects, we can get better economy of scale.

Would you like to have a multimeter watch?

On a sunny day (Fri, 4 Apr 2008 10:45:54 -0700 (PDT)) it happened linnix wrote in :

What about probes? What about if you want to measure 500V floating, the isolation. I like to keep multimeter clear from myself in some cases.

Sounds intriguing if not too huge, and reasonably functional (find some way to store probes within?). Safety concerns need to be addressed.

Best regards, Spehro Pefhany

That would have to be external, may be a finger tip cap.

There are certainly limitations, but most people just want to measure batteries anyway.

Hi Linnix,

Thanks for the information.

Mmm... maybe. If I'm holding two probes with my hands, I can imagine my wrist might not be in a good position to view the display. I guess I'd have to try it out... at one point I thought those "probe"-style multimeters (one probe is a regular probe, the other has a large body that contains the probe tip, electronics, and display) were a good idea until I realized that -- at least these days -- you're often probing small enough parts that the size of the probe body gets blocked by other components on the board.

I'm glad you're pursuing the idea, though -- there are a lot of really cool little measurement devices out there that many people here would love to see implemented.

---Joel

Now that would be the ultimate nerd tool!

However: Do your corporate lawyers know about this idea? Did they need heart medication and Maalox after learning about the idea? Just imagine uncle Leroy whipping out a couple of probe cables, sticking them in somewhere on his wrist, then reaching into his neighbor's gas furnace to see if the 240VAC is still there.

Could be limited to 12V or 14.99V or something like that. And a non-conductive case. Best regards, Spehro Pefhany

Well, I would at least remove the watch from my wrist first. The point is not to have to carry another meter. You don't have to use it in place (your wrist).

I have to carry the probes anyway. What do I gain by making the meter attach to my wrist?

Besides, I prefer that my watch be small rather than a big clunky computer that is attached to my wrist.

I had a nice old old Cassio altimeter watch. It told time and altitude (and pressure, but I never used that). It wasn't much bigger than a normal watch. It finally died. All modern altimiter wrist watches have big fancy graphs. Yuck. They are way to big/klunky for my taste.

Yes, but you know how that goes. "Oh, let's see if the uC on the gas furnace controller has juice on VCC... oops!" ... bzzzt ... *BANG*.

Sure, but there is always that one stupid user. If it doesn't say "Do not put in mouth" in multiple languages you could be in trouble already. I've seen my share of careless folks. Like when someone checked the water level in his car battery, peeking inside, with a cigarette loosely dangling between his lips.

If it's just a voltmeter, put a M or two in series with each probe wire. Same risk level as an ESD wristband (almost zero). Best regards, Spehro Pefhany

you

That would be good. But it doesn't cover the real brazen guys who place alligator clips first and then fumble it all into the wrist watch meter ;-)

Seriously, I've seen a guy who started a car, unclipped the jumper cables from the helper car so the other guy could head off to the hardware store and left the now hot cables laying on the garage floor while revving his engine.