9 replies to this topic

[BaronVonchesto]

Hello all! Happy Holidays!

I recently made the embarrassing mistake of misreading my fuel gauge, and ran my tank empty. Luckily the engine died just as a reached home, so it wasn't a big deal.

 

That got me thinking, what would it take to make a low fuel warning lamp? Since the fuel level sensor is just a variable resistor, and the fuel gauge a ohmmeter, I figured I could put a small bulb in series with the gauge just before its grounded. When the fuel is near empty, the low resistance will allow the light bulb to light up, and it should die out once there is enough fuel to make the resistance high.

 

The question though would be how much resistance of the light bulb would affect the reading of the fuel gauge. Perhaps a small relay should be used instead?

 

On another note, the engine coolant temperature sensor is just a thermistor, so any ideas on how to implement a warning lamp for that?

[Swift_General]

A small (incandescent) bulb such as a 2.2W panel light will have a resistance sufficiently low to mess up your gauge readings - and of course it wouldn't switch on as such, just vary in brightness getting dimmer as the tank empties. I think you're on the right track with a relay, however I would get a solid state relay capable of being switched on when the voltage drops below a certain present level. The resistance of the device would likely be so high as could be disregarded.

[Spider]

Low Fuel Lamp kit     https://www.spiyda.c...ght-module.html

 

I'm sure Chris at Spiyda also did a High Temp Warning Lamp, if you email him, I'm sure he'll be able to offer something. He's a very cluey bloke and also a Mini nut too.

[timmy850]

Many shops sell kits similar to these, just a temp sensor and warning light. Most seem to be at 110deg C which I think is a bit late

https://www.demon-tw...re-gagelite-kit

[BaronVonchesto]

Low Fuel Lamp kit     https://www.spiyda.c...ght-module.html

 

I'm sure Chris at Spiyda also did a High Temp Warning Lamp, if you email him, I'm sure he'll be able to offer something. He's a very cluey bloke and also a Mini nut too.

 

Thanks for the suggestion, but it looks to be exactly what im proposing too, so I dont see why i need to fork out 20 quid for it :)

[mini13]

Tight git... Lol

You could use a couple of voltage comparator modules,

https://rover.ebay.c...tm/262448537905

[Spider]

 

Low Fuel Lamp kit     https://www.spiyda.c...ght-module.html

 

I'm sure Chris at Spiyda also did a High Temp Warning Lamp, if you email him, I'm sure he'll be able to offer something. He's a very cluey bloke and also a Mini nut too.

 

Thanks for the suggestion, but it looks to be exactly what im proposing too, so I dont see why i need to fork out 20 quid for it :)

 

 

If I can suggest, while your basic idea is not a bad one, the means to implement it are not nearly as simple as you think. and Swiftgeneral touched on some of the reasons why.

 

Personally, I think this kit offers good value for money, but if it's too dear for you then I'm scratching my head wondering why you have an old / classic car.

[BaronVonchesto]

put it this way... 20 pounds to you is 110 ringgit to me, and thats not even including the cost of shipping. Its a question of spending the money I have wisely.

 

Besides, its way more fun to do it myself!

 

a voltage comparator circuit sounds like a good bet, i'll look into that. Thanks for the idea! 

[hhhh]

An advantage of the comparator circuit method is that you can set the levels wherever you like. You could even have two on each with a yellow warning and red emergency level or something similar.

[minimans]

Or you could just look at the fuel gauge and Temp. gauge a bit more and save the 110Ringit?.................................