Recall what thread he was talking about it in? Must have missed it.
7 segment like little LED dots? I always thought that the little blue battery status on my Apple laptop were classy and discrete… Maybe lined up in a circle around the switch?
Uuum apologies for awakening an old thread but I have a desire to for a small, inexpensive voltmeter, does any one know of any gems?
Usage, my camera does not like after market batteries and though it will work with them it gives no indication of the state of charge until they battery is in need of recharging.
It has occurred to me I could attach a small digital voltmeter to the battery grip attached to the camera, space is obvious limited.
I have ordered one via ebay
https://www.ebay.co.uk/itm/2-Wires-Mini-DC-2-5-30V-Voltmeter-LED-Panel-3-Digital-Display-Voltage-Meter-HDU/303095831026?ssPageName=STRK%3AMEBIDX%3AIT&var=602027118680&\_trksid=p2057872.m2749.l2649
whether or not it proves suitable is anyone’s guess.
Actually I would also like to add an on-off-on switch (tiny) as well, as the batteries (2) within the grip do not share a common connection and the camera ‘monitors’ both separately.
I would add a photo of the battery grip’s end but I don’t see how to upload a photo directly from my computer.
Thanks
These are small and good for lion but you don’t mention what battery type. These will only display anything from 2.5-3.0 volts and up depending on which color you choose. Otherwise, there is not enough volts to power the display. One good thing about them though is they can be calibrated using a multi meter and the screw (pot) on the bottom to be more precise. I actually have one of these (in red) on order so i can add to one of my battery chargers that only displays a less precise “gauge”
Thanks
Li-ion, nominal voltage 7.2V, recently charged and unused 8.2V.
Sorry, I missed the calibration pot in the advert photos, is it that what looks like a cross head in the centre of the underside? Does the accuracy of the voltmeter wander significantly over time?
Can the mounting tabs be cut off?
The one I ordered hasn’t arrived yet and I’d not be using a screw mounting in any case
If you can do this with an ATTiny85 and an oled…then I am sure a simple volt meter could be done
oh snap…check out the pico328
Uum, thanks but being honest I think that would be beyond my capabilities without a fair bit of studying. Though the size might be more suitable.
I use on my voltage sensitive Aux or tail boards a voltage comparator so I have 2 voltage levels like 3.6 and 3V to light up a different LED color
So 3.6-4.2V green
3.3-3.6V blue(yellow is pretty inefficient
3-3.3V red
Adding a 2.93V IC shuts it down below that, so no more parasitic drain of abou 0.05mA or more depending on LED brightness
I made a board to refit flashlights that has 14mm diameter with all components but this uses only 2 steps high, low warning and off, not implemented the complete shutdown so about 0.05mA remain below shut down
Oooooo got the voltmeter and it just about perfect for what I want, I am chuffed!
Now a daft question or at least it will probably seem so to you guys, is there a way to dim the display? It is very bright.
Sean, you can buy these voltmeters waaay cheaper, take a look at FastTech for example: 0.28" 3-Digit LED Voltmeter Module (3-Pack)
Use the right side drop down, many colours and assorted packs available.
I bought a 3-pack of greens long ago, they seem moddable for 3-wire common ground operation. The red wire connects to a pad nearby an unused one which is connected to it via a jumper (0 Ohm resistor). This means removing the jumper will allow the unused pad to work as signal line. Not tried it yet.
^:)
it seems to have build in resistors in the LED module so no way making it less bright
I think there is a way to make them less bright, this is adjusting the input voltage. My voltmeters work down to slightly less than 2.4V, their displays are barely visible at that point. If my above theory is correct the way to make this is to remove the signal line jumper (0 Ohm resistor) which connects it to the middle pin (power in). This way we could control the display brightness by adjusting the middle pin input voltage.
^:)
Barkuti, thanks, I will have a look at the next one, I ordered some from China, significantly cheaper than the first. The display unit is embedded in epoxy inside the battery grip end so I can’t try any modifications to the connections.
The display/voltmeter is installed in the end of the camera’s battery grip and, with two momentary contact push-button micro switches as selectors, does a perfect job.
I put shoulders of epoxy putty around the the protruding parts, there isn’t much protrusion, and am just waiting for some tinted plastic to arrive to add that as a cover and dimmer for the display.
I recently ordered some stuff from CZB6721960 Store and found a crazy wide selection of voltmeters there, among which here is rhe very first search hit:
They totally look like 3-wire versions of the FastTech ones, so a full blown yes to what I said before.
Cheers ^:)