HELP me build a gas gauge????

[browningbuck]

here is why i cant use 10...i could use sx like i said earlier..not enough room

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this is a small little buisness i have putting intergrated gear indicators on bikes (the 7 seg. display in the middle) then bunches of people wanted me to design a fuel gauges and thats where i am at (the fuel leds are just photoshoped as you can tell ) BOY I LOVE LEDs

 

[chemelec]

Well there are Small LED's and there are SMALLER LED's.

I have some here that are only 1/16 Inch Square.
Side by Side, 10 would be 5/8 Inch Long.

But Anyway, Have FUN.

GARY

here is why i cant use 10...i could use sx like i said earlier..not enough room

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this is a small little buisness i have putting intergrated gear indicators on bikes (the 7 seg. display in the middle) then bunches of people wanted me to design a fuel gauges and thats where i am at (the fuel leds are just photoshoped as you can tell ) BOY I LOVE LEDs

 

[Leftyretro]

Very cool looking design.

As said already there are a zillion different LED designs. You might want to consider looking around before freezing your project.

Here are just a few ideas:

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Lefty

 

[browningbuck]

only reason i can down grade in size is due to mcd they will in the end have a photo resistor, and have to be bright enough in the day to be clairly visable, on a motorcycle, and plus 5 is cheaper and more simple for me to sell (less holes i have to drill in an $80 face plate)

i still have a prob with getting this in bar mode instead of dot i have tried as said before connecting pin 3 and 9 (no luck) any sugestions????? and the project has not been put on pause it was just the weekend i had to work on 3 sets of gauges

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i kinda liked this one a little

 

[TrevorP]

To get it in bar mode simply provide power to the Mode Node...if that doesn't work then something is messed and you should try another chip of the same type.

 

[browningbuck]

okay i did hook up mode to power, but nothing...i had to get an NTE1508 instead of the LM3914 but it says its a dot / bar????? and did try a new chip..nothing different

 

[Darth Bagel]

https://www.electro-tech-online.com/custompdfs/2007/12/nte1508.pdf

Note 4. Bar mode results when Pin9 is within 20mV of V+. Dot mode results when Pin9 is pulled atleast 200mV below V+ or left open circuit. LED No. 10 (Pin10 output current) is disabled if Pin9 is pulled 0.9V or more below VLED.

Have you checked the voltage on the mode node yet, as in with an instrument of some sort?

 

[browningbuck]

they measure within .001 volt of each other ???? it seems like this should work

 

[browningbuck]

https://www.electro-tech-online.com/attachments/fuel-gif.15847/


okay so i am working out some bugs still on this and was wondering where to stick a photo resistor on this cicuit to make it dim when there isnt much light???? i also ordered a new chip to see if that was the problem on getting the thing to light up as Bar instead of dot, being connecting pin nine to V+ didnt work

 

[matk95]

looks like a nice display

if you dont want to have to drill loads of holes then you could use a led bargraph

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they are avilible in many colours and are small enoughf to fit esily onto the space you have


one place to ordere
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but they are avalible at lots of places

 

[chemelec]

https://www.electro-tech-online.com/attachments/fuel-gif.15847/


okay so i am working out some bugs still on this and was wondering where to stick a photo resistor on this cicuit to make it dim when there isnt much light???? i also ordered a new chip to see if that was the problem on getting the thing to light up as Bar instead of dot, being connecting pin nine to V+ didnt work

I Doubt this can Work in Bar Mode, Because my design is running the display in Reverse.

To get Bar Mode, you would require Reversing the input voltage with an Op-amp and operating in Normal mode.

 

[browningbuck]

oh crap so i can either ask everyone how to wire up an Op-amp, or as how to wire this up to work in normal mode with out an op-amp....


anyone feel like helping me out?????

Chemelec you have been kicking butt, and thanks for everything

 

[chemelec]

oh crap so i can either ask everyone how to wire up an Op-amp, or as how to wire this up to work in normal mode with out an op-amp....


anyone feel like helping me out?????

Chemelec you have been kicking butt, and thanks for everything

If you Email me with the Info, I'll see about doing up a Proto-type circuit up for you, with the Inverter circuit and the bar display.

I Need All the Info Again, including those resistances of the gas sender unit!

And I would Definately Recommend you go with 10 Leds, 5 won't give enough accuracy.

Gary

 

[SPDCHK]

oh crap so i can either ask everyone how to wire up an Op-amp, or as how to wire this up to work in normal mode with out an op-amp....


anyone feel like helping me out?????

Chemelec you have been kicking butt, and thanks for everything

BTW. You do not have your location filled in. Where in the world are you?

 

[browningbuck]

hey guys i have a 12V system and need help to figure out a solution to this problem...okay i dont need help...i need some one to hold my hand through this

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okay here is the information....

the systemwith 5 leds has been working FLAWLESSLY...i should get you a vid up tonight when i get to my camera. it is sooooo accurate that i couldnt ask for anything more. but i am still willing to start with a fresh idea so tell me what else you would need. if anything i think 6 would be BEST... so that i could have 5 lights noting in a bar like this picture and the 6th kicking on the gas light like so


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[Darth Bagel]

Could you draw a schematic of what you've got right now? I'm a little bit confused.

 

[browningbuck]

this is what i have so far.... i dont think it will EVER work in Bar mode due to the theory behind it, so i think i might need to start from scratch...and i want to do it with a photoresistor and 6 leds. let me know if you can help....GOD you guys are BAD A$$ SOBs wiht this stuff and i thank you for everything.

Brian

 

[on1aag]

Hi Browningbuck,

Maybe you need a different approach, I think the circuit is too
complicated. If you send a constant current through the gas
gauge the voltage across it's terminals will be proportional to
it's resistance. Then you can measure this voltage with the
LM3914, nothing to it but, there always is a but . . .
The LM3914 should drive five leds, the minimum level should
correspond to 12 hm: , the maximum level to 132 hm: .
No problem (?) if you could build your own LM3914 to meet
your specifications, in practice there is a minimum level and
the maximum level is ten times the minimum level.
So I decided to apply a constant current of 10 mA to the gas
gauge, set the lowest indicator level for the LM3914 to 128 mV
and the highest indicator level to 1280 mV.
Which also means that there are ten indicator levels on five leds.
Off, half brightness, full brightness.
I also decreased the led drive current of the LM3914 to approx.
5 mA per output. There is only one difficulty left and that's the
construction, everything that is connected to ground should be
connected directly to one single point.

on1aag.

 

[chemelec]

this is what i have so far.... i dont think it will EVER work in Bar mode due to the theory behind it, so i think i might need to start from scratch...and i want to do it with a photoresistor and 6 leds. let me know if you can help....GOD you guys are BAD A$$ SOBs wiht this stuff and i thank you for everything.

Brian

I Already Told you it Won;t work in Bar Mode the way I did it. But I can fix that if you give me a bit of time.

Too many things to do all at once.

 

[Super_voip]

A simple solution for the bar display may be to mount the LEDS in reverse order.