LED alarm panel

[Zippy2]

If anyone is bored and looking for something to do, I need some help. I need to build an LED array that would serve as a tank level indicator.  15 each 3 mm LED's would be through panel mounted, all green except the "top" 4 would be red.

The input signal is 4-20 mA from a level transmitter proportional to the level. The voltage output in the loop is 5 vdc and limited to about 30 mA.  As the signal rises, the LED's would light, indicating another foot of level. I'm thinking that the last red LEd would flash. This is an unsual application because it needs to be visible from a distance. I'm doing it for a friend of mine in a startup business. I'm donating some wireless stuff that transmits the level from the sensor to a receiver located in the panel. There are lots of other ways to do this but it seems as if this (LED indication)  would be the least expensive in terms of buyout.

I don't know what to use as a controller. My background is industrial instrumentation, pressure, flow, valves and positioners used primarily in chemical, pharm and refininery apps. I can bread board, build and understand simple circuits but I have zero experience with hands on micro controllers. I normally just buy the display or indicator. (before I retired)  But nothing quite fits here unless it costs big $ and there is little $ available. The project is necesary to meet State and the EPA requirments and was unexpected. I have some experience with programming but mostly with products like Visual Basic and Visual Studio but only for PC programs, data aquisition. And I'm not very good either. But I can usually get it done after a fashion.

I would appreciate it if you can point me in the right direction, to a recent thread or web site. I realize my info is pretty sketchy but at this point, I'll be designing everything else around the controller.

Thanks / Charlie

[Rob]

Wow, off the top of my head I'd say an op-amp to convert current to voltage and a LM3914 to drive the bargraph. Solution under three bucks if that works for you.

Er, notice you wanted 15, so you'd cascade 2 LM3914s as described in the datasheet.

[justDIY]

yea, I was gonna suggest the same solution

as for the top most led, blinking ... well, just buy a pre-fab blinkin led and you're set   it'll hook up the exact same as a regular led, the blinker circuit is self contained.

[Rob]

That is how I'd do the blinker too. Sometimes it doesn't pay to overthink things.

[Zippy2]

That's just too good guys. Thanks and I'll let you know how it comes out. Just as soon as I get my laptop back together.