SparkFun Forums

[Belial88]

Guise, this is going to look SO awesome... i will provide pics ^^

I got a question about wiring - say I did want to use the source for power, would I attach green and red wires (measure/(+)) or just leave measure hanging?

I'm kinda interested in having one of these on my car battery, just like an alert for if it goes too low so I stop running out of battery. Would be really cool to have it alarm if it hits a certain voltage point. I guess that'd be a mod for a trinket...

So googling "4 digit voltmeter blue" and ones with 3 wires and no big components on the back is what I need to be looking for (3 1/2 never have low enough minimum range, and 5 is expensive needlessly and ugly)

I think I'm going to go with this one. Cheaper than aboves and no mess of hot glue I have to burn through. It's got a higher max range so I'm guessing it's more inaccurate (despite same official spec) but w/e, this is more novelty and 3 digits is really as much accuracy as I need.

http://www.ebay.com/itm/3-lines-4-Digit ... 27d8fff003
$4.80, goes to 30v

[lyndon]

Accuracy is typically specified as a percentage of full range so 0.3% of 33V is 0.11V, + 1 digit at that range, let's say it's on a .01 V resolution, would be 0.12V accuracy.

[Belial88]

Oh wow, I wouldn't have figured that. So basically I want to get the voltmeter with the lowest maximum range. Which means either tha 30v one I just picked, or the 3.3v one earlier that I had to clear out all the gunk from.

I messaged the sellers and they said they couldnt sell it separate, ill email them again saying my purchase is contingent on it. Or maybe I'll see if I can findvit sold separately elsewhere.

[lyndon]

Realistically, 0.12V accuracy for those meters is pretty good. I wouldn't expect anything better than that.

[Belial88]

yea but i can't have it say 1.5v when its really 1.6v. saying 1.55v when it's 1.6 isn't really good either. Acceptable woul be like 1.58v when it's 1.6v maybe.

So I'll have to find one with either high accuracy or ~3v max.

I think I'm going to abandon this project at the moment, I got the info I needed to do this in the future (like for a car or another pc, very cool stuff). I'm going to continue this topic over at : https://forum.sparkfun.com/viewtopic.php?f=42&t=36671

Where I think I'll combine my cpu temps display mod with this one. Even though I want to use different inputs for temps(software) and voltages (hardware), maybe a MCU can display these inputs on the same display.