blakep82
|
| posted on 18/12/08 at 09:57 PM |
|
|
LED vu meter fuel guage
how easy would it be to set one of the LED VU meter things to be a fuel guage?
are these VU meters voltage driven? like, do more lights light up when the voltage increases? would it just be simple enough to hook one up to the
fuel level sensor, with a variable resistor to calibrate?
________________________
IVA manual link http://www.businesslink.gov.uk/bdotg/action/detail?type=RESOURCES&itemId=1081997083
don't write OT on a new thread title, you're creating the topic, everything you write is very much ON topic!
|
|
|
|
|
SteveWalker
|
| posted on 18/12/08 at 10:18 PM |
|
|
Take a look at the datasheet for the LM3914, LM3915 and LM3916.
|
|
|
rf900rush
|
| posted on 19/12/08 at 07:31 AM |
|
|
Not as easy as you first think.
From memory I think the fuel sender if a variable resistor with approx. 200-300 ohms.
You need to convert this to a voltage suitable for the led meter.
My car has a microcontroller setup display using calibration tables similar to megasquirt.
I still think I prefere the old way.
8 leds does not give me confidence in how much fuel is left.
Martin
|
|
|
MikeRJ
|
| posted on 19/12/08 at 12:40 PM |
|
|
I'm a firm believer in nice, easy to read analogue gauges, but I know some like digital dashes.
Jaycar do a simple and cheap voltage monitor kit based on the LM3194
that could be adapted for your needs.
You will have to turn the resistance into a voltage as Martin has mentioned, but this is fairly easy simply using another resistor as part of the
potential divider. The slightly trickier parts are:
1) You really need a regulated voltage to feed the potential divider. If fed straight from the battery voltage your fuel gauge will vary with the
state of charge of the battery as well as fuel level.
2) You will need a low pass filter to prevent the gauge responding instantly to the fuel level as it sloshes around. As the Jaycar circuit has a high
impedance input this could be a simple RC network with a long enough time constant (perhaps 5-10 seconds or so should be adequate).
|
|
|
iank
|
| posted on 19/12/08 at 12:48 PM |
|
|
There's a circuit on here that allows each of the levels to be calibrated.
http://www.mez.co.uk/ms13.html
--
Never argue with an idiot. They drag you down to their level, then beat you with experience.
Anonymous
|
|
|
blakep82
|
| posted on 20/12/08 at 11:53 AM |
|
|
blimey. more complicated than i thought... might just have a normal gauge...
cheers guys
________________________
IVA manual link http://www.businesslink.gov.uk/bdotg/action/detail?type=RESOURCES&itemId=1081997083
don't write OT on a new thread title, you're creating the topic, everything you write is very much ON topic!
|
|
|
