Another question for the experts
Thread Starter
Joined: Oct 2000
Posts: 1,921
Likes: 0
From: Lisbon
I am about to install this set of gauges:
They have a programmable threshold that turns on a red light on the gauge once reached.
This is a useful function, but I am planning to install the gauges in the headunit location, so I will only see it if the lid is open.
The gauges have a 3 contact connector at the back for an addition warning mechanism. Defi actually sells a unit that you can attach there and that blinks when the threshold is reached. Unfortunately it is a bit to big for installation. I'd rather have an audilble alarm or a small led instead.
I have measured the voltage across those 3 pins and these are the results:
Warning light OFF or ON:
Fom pin A to ground +12V
From pin B to ground +6V
From pin C to ground 0V
From pin A to pin B +6V
Voltages dependenT on warning light:
From pin A to pin C 0V (off) 6V (on)
From pin B to pin C 0V (off) 3V (on)
How hard is to get an audible alarm or blinking (optional) led out of this? Can I just power an LED or buzzer from A and C? Do I need additional information?
Thanks for any help.
They have a programmable threshold that turns on a red light on the gauge once reached.
This is a useful function, but I am planning to install the gauges in the headunit location, so I will only see it if the lid is open.
The gauges have a 3 contact connector at the back for an addition warning mechanism. Defi actually sells a unit that you can attach there and that blinks when the threshold is reached. Unfortunately it is a bit to big for installation. I'd rather have an audilble alarm or a small led instead.
I have measured the voltage across those 3 pins and these are the results:
Warning light OFF or ON:
Fom pin A to ground +12V
From pin B to ground +6V
From pin C to ground 0V
From pin A to pin B +6V
Voltages dependenT on warning light:
From pin A to pin C 0V (off) 6V (on)
From pin B to pin C 0V (off) 3V (on)
How hard is to get an audible alarm or blinking (optional) led out of this? Can I just power an LED or buzzer from A and C? Do I need additional information?
Thanks for any help.
Thread Starter
Joined: Oct 2000
Posts: 1,921
Likes: 0
From: Lisbon
Just occured to me that the buzzer will not do. Some thesholds are lower thresholds, like oil pressure, so the buzzer would go off from the time you turn ignition on til starting the engine. Will have to be an LED solution.
Honorary Member
Joined: May 2001
Posts: 2,121
Likes: 3
From: Indian Land SC
[QUOTE]Originally posted by Luis
[B]I have measured the voltage across those 3 pins and these are the results:
Warning light OFF or ON:
Fom pin A to ground +12V
From pin B to ground +6V
From pin C to ground 0V
From pin A to pin B +6V
[B]I have measured the voltage across those 3 pins and these are the results:
Warning light OFF or ON:
Fom pin A to ground +12V
From pin B to ground +6V
From pin C to ground 0V
From pin A to pin B +6V
Thread Starter
Joined: Oct 2000
Posts: 1,921
Likes: 0
From: Lisbon
Thanks, modifry.
I do not have a resistor at hand, but I have used my ampmeter.
From A to C I see 7.6 ma when the warning light is on and 0 when off.
From A to ground I see 15 ma in all conditions, from C to ground I see 17 micro a when the warning light is on and 0 when off. Grounding pin B makes the needle jump to max so I didn't test that any further.
I don't know if this starting to sound like a riddle, but can I power a LED or a buzzer from A & C?
I do not have a resistor at hand, but I have used my ampmeter.
From A to C I see 7.6 ma when the warning light is on and 0 when off.
From A to ground I see 15 ma in all conditions, from C to ground I see 17 micro a when the warning light is on and 0 when off. Grounding pin B makes the needle jump to max so I didn't test that any further.
I don't know if this starting to sound like a riddle, but can I power a LED or a buzzer from A & C?
Thread Starter
Joined: Oct 2000
Posts: 1,921
Likes: 0
From: Lisbon
Ok, never mind...
I went ahead and bought a 3V LED and connected it to the terminals that show a voltage change when the warning light is on.
When connected from A to C the LED blinks when the threshold is reached. It stays mute otherwise. The LED itself is a high intensity one but non-blinking, so the actual blinking is being provided by the gauge.
I did not measure the forward current thru the LED but no smoke came out
, the LED did not overheat, and the gauge did not melt ( yeah! ).
... expert opinion no longer actively sought, but still accepted
.
I went ahead and bought a 3V LED and connected it to the terminals that show a voltage change when the warning light is on.
When connected from A to C the LED blinks when the threshold is reached. It stays mute otherwise. The LED itself is a high intensity one but non-blinking, so the actual blinking is being provided by the gauge.
I did not measure the forward current thru the LED but no smoke came out
, the LED did not overheat, and the gauge did not melt ( yeah! ).... expert opinion no longer actively sought, but still accepted
.
Registered User
Joined: Oct 2000
Posts: 7,134
Likes: 3
From: Columbia, MD
Originally posted by Luis
I did not measure the forward current thru the LED but no smoke came out , the LED did not overheat, and the gauge did not melt ( yeah! ).
I did not measure the forward current thru the LED but no smoke came out
, the LED did not overheat, and the gauge did not melt ( yeah! ).
Trending Topics
Thread Starter
Joined: Oct 2000
Posts: 1,921
Likes: 0
From: Lisbon
Thanks guys...
What about this challenge?
The gauges thresholds are upper or lower thresholds depending on the gauge function.
For instance, on the water temperature gauge you set an upper threshold that once reached triggers the warning light/terminals.
The oil pressure works the opposite way. That is, you set a lower threshold, and when the oil pressure drops below that, the same thing happens.
The challenge is this: The oil temperature is an upper threshold, but I'd rather use it as a lower threshold.
I'll explain:
Overheating is easily detected on the engine coolant gauge, so for this effect the oil temperature threshold is redundant. What would be useful would be to use the oil temperature threshold for an "unsafe to redline" warning LED.
But for this I would need to invert its operating mode, that is, when no voltage is present on the A to C terminals I would light up a LED (I could get a blinking LED for this, for simplicity sake), and when the +6v pulses on the same terminals are present then I need to turn the LED off. It's a bit more involved than just a NOT circuit, isn't it?
How hard is this? Do you want to volunteer a diagram?
What about this challenge?
The gauges thresholds are upper or lower thresholds depending on the gauge function.
For instance, on the water temperature gauge you set an upper threshold that once reached triggers the warning light/terminals.
The oil pressure works the opposite way. That is, you set a lower threshold, and when the oil pressure drops below that, the same thing happens.
The challenge is this: The oil temperature is an upper threshold, but I'd rather use it as a lower threshold.
I'll explain:
Overheating is easily detected on the engine coolant gauge, so for this effect the oil temperature threshold is redundant. What would be useful would be to use the oil temperature threshold for an "unsafe to redline" warning LED.
But for this I would need to invert its operating mode, that is, when no voltage is present on the A to C terminals I would light up a LED (I could get a blinking LED for this, for simplicity sake), and when the +6v pulses on the same terminals are present then I need to turn the LED off. It's a bit more involved than just a NOT circuit, isn't it?
How hard is this? Do you want to volunteer a diagram?
