whos interested if i make these?

[dieselboy]

At least in a surf you can't scuff the wheels on the curb!

dont, just before xmas 2005 i was having a hard time. nothing was going right. then i pulled in a shell garage to get some fuel on the way home. some bird was waiting at the entrance thinking where to pull up for fuel, stopping me from coming in the garage and making me block up a lane on a dual carriage way..
eventually she moved and i went over to the pump on the wrong side of my car (e30 bmw, 18" wheels 215/35/18) and pulled close to the pump so it would reach. there was a metal curb i didnt see and it took a chunk right out of it. brand new, now one down 3 to go.
after this it was a steady slope down hill. someone didnt give way to me when there were parked cars on their side of road NOT mine, and forced me into the curb a tiny bit.
then i was going sideways off a round about (so my fault then) into a road, on full opposite lock i couldnt turn any more, there was a car coming, so i turned off lock to move over and the front wheel just kissed the kurb.. it hardly showed that much though
then the final was when someone pulled out in front of me one morning on way to work. it was on a bend, i slammed on brakes slid right into the kerb doing both passenger alloys completely. they were cracked and bent.
so, from £800 down to £20 s$$$$ (although 1 was mint, and 1 was almost mint i wanted rid) all within about 2 years. good depreciation i think

[dieselboy]

My point is though, you cant just connect an LED to a temp sensor and expect it to light at the correct point just using a v/div network of resistors.

i know
i was going to work everything out..
was thinking of a variable resistor type thing so i can tune it.

[Apache]

i know
i was going to work everything out..
was thinking of a variable resistor type thing so i can tune it.

With a comparator so you can set the switch on point?

Just a simple variable resistor with no active components will result in an LED that comes on dim and slowly gets brighter as more volts are applied (hotter the engine gets).

Check this out...

http://www.uoguelph.ca/~antoon/gadgets/741/741.html

There's some simple comparators down the page. The one in fig 14 would probably be suitable. You could even drive a small transistor as well as the LED to power a small audio warning buzzer. It would be good engineering practice to regulate the voltage you use to power the device rather than just using the battery as a ref as this varies between 11 odd volts and 14.4 in a healthy system.

[Gupster]

The temp sender was a new unit not hooking anything to the origional one.

Sounds like this item is getting too over engineered for me . Cant beat a simple relay switched system. If something goes wrong you just have to pop in a new 30a relay, check the fuse, or wireing. K.I.S Keep It Simple

Cheers,

[dieselboy]

yea but i like the ideas coming in..
the issue i see is that ive read all these stories of peoples head being popped. could be due to a faulty fan, faulty rad cap (like me but i noticed) or thermostat not opening.. just to name a few
in a system that otherwise works if something like the above goes, the temp will rise into the red correct? and then at this point the pressure will be too great for the rad cap to hold and make it blow fluid... ?

i just wanted to get an early warning system, that was that one step ahead.

if the persons temp gauge doesnt work, or doesnt show half way on their dash when warm because its faulty (and not because the thermostat has been taken out) then i understand that wiring it to that place wouldnt let the circtuit work. but if your driving about without a working sensor then your very brave indeed.

wiring to the original car wiring to the sensor ive thought is the easiest option available. tbh i dont like getting greasy anymore or sitting under cars. ive been behind a computer screen too long. some people cant physically get under, and/or dont have the tools (also like me) to aftermarket fit another sensor.

from the cool ideas that have been put in it seems there are better options definately. keep the ideas coming

what was that thing they had, where loads of people threw ideas together... think bin?

[dieselboy]

UPDATE::
im going to also make an add-on, so when the circuit picks up a certain temperature, it actually calls Stevo and TonN, orders a head, and books you a slot into Tonys garage

[dieselboy]

in a system that otherwise works if something like the above goes, the temp will rise into the red correct? and then at this point the pressure will be too great for the rad cap to hold and make it blow fluid... ?

serious update: how quick would this happen? i might have to put a timing circuit in there as well so that even if the temp goes down because you have lost water, the light stays on. but will the head be blown already at this point?

[captain_chaos]

serious update: how quick would this happen? i might have to put a timing circuit in there as well so that even if the temp goes down because you have lost water, the light stays on. but will the head be blown already at this point?

At that point will you have a warning light come on saying "it's buggered mate"

[dieselboy]

o rly!!? ive never seen that one haha

[Vultch]

engine temp

Or.. you can buy fairly cheap digital thermometers from Maplin/ B&Q etc. mount display in dash and run wire (with temp sensor) to engine bay, tie wrap sensor to ...a rad hose/top of rad/ somewhere on the cooling system or even the head.
Keep an eye on the digital display to determine normal engine operating temp and should things start to go wrong in the future you have another temp gauge to refer to.

[dieselboy]

Just a simple variable resistor with no active components will result in an LED that comes on dim and slowly gets brighter as more volts are applied

this will happen only if the variable resistor is set before the LED i think

[Apache]

this will happen only if the variable resistor is set before the LED i think

No. honest. The output from the sensor is a variable voltage derived from (I assume) a PTC element in the sensor. You really do need a positive 'on'.

(I've been in electronic engineering for 23 years and I seem to remember we've been here before when someone suggested we dont know why a radio works, we just accept it does)

Check out the circuits on the link I posted. It's not that hard. Have a go!

[MattF]

You will also need to build in some hysterysis so it doesn't oscillate between on and off at the selected point. You want it to come on and stay on when the danger point is reached.

Christ. Why'd you mention that. You take the fun out of everything. Novel spelling of hysteresis, btw.

[MattF]

Andy, you're missing an opportunity here. He really is an I.T boy......

[dieselboy]

No. honest. The output from the sensor is a variable voltage derived from (I assume) a PTC element in the sensor. You really do need a positive 'on'.

(I've been in electronic engineering for 23 years and I seem to remember we've been here before when someone suggested we dont know why a radio works, we just accept it does)

Check out the circuits on the link I posted. It's not that hard. Have a go!

there will be a constant on from the battery, and the sensing wire from the sensor is just to sense.
do you want to help me plan this?