DIY or Assembled 10 LED Voltmeter - Works Well

[ShokWaveRider]

Hi all:

I built a simple DIY 10 LED voltmeter. I made mine to go from 4.2v to 6v in .2v increments. It uses an NTE 1508 and a few resistors, caps and a Diode (Reverse Polarity Protection). I modified one I use for a car 12v system.

10 off 1.8mm, 3mm or 5mm LEDS. Dependinh on your application.

I uses 10ma and lights 1 LED at a time. Under 4.1v all off, 4.2v Number 1 LED On. 5v Number 5 LED On 6v or over Number 10 on etc.

These are the LEDS Choices I have used:

http://www.impconcepts.com/gaugesforsale/common/ledindicators.jpg

Just thought I would share.

5mm LEDS

http://www.impconcepts.com/gaugesforsale/common/afmkitledoptions-5mm.jpg

3mm LEDS

http://www.impconcepts.com/gaugesforsale/common/afmkitledoptions-3mm.jpg

The kit of Parts costs about $10 if you build it on an RS Proto Board but it is bulky, or I made myself a PCB which cost a lot more because I only made small quantities. It is very light and measures about 1.2" x 0.5" I mount the LEDS on the model and then wire them to the board (or visa versa depending on the application) but it could be made into a single unit with 2 wires (+ and - Voltage). It is easily installed in Foamies with the LEDS poking through the fuse.

PCB I Designed and Use looks something like this.

http://www.impconcepts.com/gaugesforsale/airfuelmeter/afmkit-2.jpg

Just thought I would share.

SWR

[Zeta Phoenix]

So the NTE 1508 is a replacement for a LM3914?

Nice board, tho when I made mine I stuck with single sided to make it easier to make.

-Jon

[Afroman]

Sweet! It looks really nice! Post a picture of the whole board soldered up with all the LEDs in it. I like the rainbow you've got going on.

[Matt Edwards]

That does indeed look neat. I noptice you have 11 holes for your LEDs. I take it you are busing the common power lead of board.

however NTE 1508 are not widely available and the future looks grim as they are not RoHS compliant.
Has any looked at the LM3914 device. is it equivalent to the NTE1508?

Cheers
Matt

[andrew b]

Thats a great little circuit you have made up, well done :)

[ShokWaveRider]

That does indeed look neat. I notice you have 11 holes for your LEDs. I take it you are busing the common power lead of board.

however NTE 1508 are not widely available and the future looks grim as they are not RoHS compliant.
Has any looked at the LM3914 device. is it equivalent to the NTE1508?

Cheers
Matt

It works with lm3914s fine. I use the mil spec chips because the lm3914 is notorious for drifting. Just my observations. In my boost gauges it is imperative I achieve accuracy to 0.125 psi. So I found for the cost mil spec devices were best. I buy them in quantities of 1000 RoHS so I always have a good stock. Not sure if folks here would have access to Mil Spec chips so regular would do but there may be a small acuracy issue from chip to chip. All Resistors are 1% and must be in my finding or you need to select them.

I actually sell these for cars from my website for 10.5 - 15v I just modified it for my RC application.

The 11th hole is common Anode on the LEDS.

I could provide a kit I suppose. It would have to be a lot cheaper than I charge the car guys though. :)

It is the PCB that is expensive, not the parts. I only get them 10 at a time as I do not sell many. The mil spec chips are about 3x a regular chip but are 1% vs 10% tolerance. I have not tried the circuit with a regular 3914.

As i said this was a retrofit of my other Voltage Gauge for the cars.

SWR