alternative to ICL7107

Thread Starter

erice1984

Joined Jun 9, 2007
16
I guess myquestion would be is there an alternative part made by a different company, or maybe something with an Analog to Digital converter.

Anyhow I am a certified automotive technician and I have a tank in the trunk for water/alchohol injection system, and the level sensor operates on 0-90 ohms, 0 being empty and 90 being full.

Instead of using op amps, and a bargraph LED display I figure I could make use of the digital components and make something that reads 0-99% fluid levels instead of displaying the level in 1/4 incriments.
 

lightingman

Joined Apr 19, 2007
374
Hi....Very simple with a PIC Micro....I have got this system on my Mini Coopers twin tanks.....Give me a few days, and I wil work something out for you.....Daniel..
 

Thread Starter

erice1984

Joined Jun 9, 2007
16
Thanks Daniel,

I have no experience with PIC, and I dont know any language to program those guys with.

only languages I have messed around with is IRC, Java, HTML, and a little VB

or the tools to flash with.
 

lightingman

Joined Apr 19, 2007
374
Don't wory !!!!I can do this with a PIC16F628, I can write the code program it for you, and send it to you....A couple of questions !! ........ do you want it with an lcd(back lit), or LED (red or green) display....If in an LCD, what else do you want it to display?.... (You have 2 x lines of 16 charaters to use)....Also are the sensor connections floating, or is one side connected to +V or ground?................Daniel.
 

Thread Starter

erice1984

Joined Jun 9, 2007
16
sensor has +5vdc supply and then the sensor wire coming back to the PCB ya know to measure voltage drop etc. then to ground. The sensor is basically jus a variable resistor 0-90 ohm range

I am really thankful for what you are willing to do, I might add other stuff into it later like Flow for the W/A inj and stuff, maybe other novelty things like est. time I can drive the car before I run out of the mixture.

I like doing this kind of stuff for hobby, my Dad is an electrical engineer and I am going to go to school for automotive engineering (basically mech eng)

and learning how to program will not be hard, just time consuming.

All I ask for is to help me stay pointed in the right direction because to me there are a lot of IC choices and I don't exactly know what or which ones are best for what I want. But the answer seems obvious it will have to be programmed.

Wow, just looked at the datasheet for the PIC controller... thats a lot! and a lot of learning for me.
 

lightingman

Joined Apr 19, 2007
374
Hi..I did the thing last night, and to be honest it is only about 30 lines of code for the LCD version, and 120 lines of code for the LED version (3 digits 0 - 100%) .......I will sort all the details out over the weekend, and get them to you....Daniel.
 

lightingman

Joined Apr 19, 2007
374
Hi again...Just a bit more info:- are you saying that the sensor is connected as a potential divider I.E. +5v one end and ground the other, and the wiper as output, or is it just +5v one end and an open output.....Also, is the +5 volt supply to the sensor regulated?.....I made a little mistake as the 16F628 does not have A/D converters, I have used a 16F877.....Daniel.
 

SgtWookie

Joined Jul 17, 2007
22,230
A bit late in the game, but you could use an LM3914 for that. One single LM3914 contains 10 comparator circuits to drive 10 LED segments, in either dot or bar mode. Of course, your input voltage would need to be a linear function in order to represent anything close to what your tank actually contains; and few of such indicators are (linear). Such containers are generally an irregular shape, and the voltage divider network (potentiometer) swings in an arc; the level indicator seems to stay on full for a LONG time, then drops rapidly through most of the range and slows to a crawl near empty.

Scaling via a lookup table in the microcontroller would be one easy way to get around such nuisances.
 
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