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Parking brake warning light for a 71?
#31
If you're interested, I believe I can design a simple logic circuit using two brake pressure (light) switches and three small relays. It could either be momentary, and just come on when the brake pedal is pressed and one side shows a fault, or stay on until reset.



“If you can't explain it simply, you don't understand it well enough.”
--Albert Einstein
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#32
(07-02-2019, 12:08 PM)Don C Wrote: If you're interested, I believe I can design a simple logic circuit using two brake pressure (light) switches and three small relays. It could either be momentary, and just come on when the brake pedal is pressed and one side shows a fault, or stay on until reset.
I don't know if we are thinking the same, but at some point I thought I could use the signal from the brake pedal and the pressure sensor on the Wilwood combination valve. If there is a signal from the brake pedal and no signal from the pressure signal then the idiot light should light up. There may have to be a slight delay of milliseconds so the idiot light is not trigger too early. I don't know if this is what you were thinking.

        [Image: 20160929_171923_edit2_small.jpg]

1971 M-Code Mach 1 w/Ram Air, 408 stroker, 285/291 0.558" roller cam, Blue Thunder intake, TKO600, Hooker headers with electric cut-offs, FiTech EFI w/ RobBMC PowerSurge pump
Strange center section with Truetrac, 3.5 gear and 31 spline axles, 4-wheel disc brakes
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#33
Interesting thoughts indeed, but a bit over my head. I think logically, not electronically. I don't have my car home right now, painting the garage floor this week, but when I get that done, I'll be able to look into a solution that works for me. There's been some great ideas as I said previously. I'll post what I do later, but in the mean time, I'm all 'ears' for other ideas.
Geoff.

I learn something new every day!
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#34
(07-02-2019, 07:00 PM)Stanglover Wrote:   I'll post what I do later, but in the mean time, I'm all 'ears' for other ideas.
Geoff.
Oh, my MIL will take care of your ears.  She's very good at biting them off every moment she gets....

She's still available if anyone is interested.

Let me check your shorts!
http://midlifeharness.com

[Image: Flamicon2.jpg]


[Image: oldfart.png]
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#35
(07-02-2019, 12:52 PM)tony-muscle Wrote:
(07-02-2019, 12:08 PM)Don C Wrote: If you're interested, I believe I can design a simple logic circuit using two brake pressure (light) switches and three small relays. It could either be momentary, and just come on when the brake pedal is pressed and one side shows a fault, or stay on until reset.
I don't know if we are thinking the same, but at some point I thought I could use the signal from the brake pedal and the pressure sensor on the Wilwood combination valve. If there is a signal from the brake pedal and no signal from the pressure signal then the idiot light should light up. There may have to be a slight delay of milliseconds so the idiot light is not trigger too early. I don't know if this is what you were thinking.
Yes, that is exactly the same, just using two different sources. And yes, I thought about the timing of both switches. I thought about using a time delay relay for triggering the dash light. Just using three normal relays would often result in momentary blips of the dash light. A time delay relay would be essential if a latching relay were used for triggering the dash light, and keeping it on. I believe the latching relay could be set up to either stay on until it was manualy reset, or to reset every time the ignition switch is turned off. The second scenario would be my preferred. A simple time delay circuit could also be used instead of a time delay relay.



“If you can't explain it simply, you don't understand it well enough.”
--Albert Einstein
  Reply
#36
(07-02-2019, 10:09 PM)Don C Wrote:
(07-02-2019, 12:52 PM)tony-muscle Wrote:
(07-02-2019, 12:08 PM)Don C Wrote: If you're interested, I believe I can design a simple logic circuit using two brake pressure (light) switches and three small relays. It could either be momentary, and just come on when the brake pedal is pressed and one side shows a fault, or stay on until reset.
I don't know if we are thinking the same, but at some point I thought I could use the signal from the brake pedal and the pressure sensor on the Wilwood combination valve. If there is a signal from the brake pedal and no signal from the pressure signal then the idiot light should light up. There may have to be a slight delay of milliseconds so the idiot light is not trigger too early. I don't know if this is what you were thinking.
Yes, that is exactly the same, just using two different sources. And yes, I thought about the timing of both switches. I thought about using a time delay relay for triggering the dash light. Just using three normal relays would often result in momentary blips of the dash light. A time delay relay would be essential if a latching relay were used for triggering the dash light, and keeping it on. I believe the latching relay could be set up to either stay on until it was manualy reset, or to reset every time the ignition switch is turned off. The second scenario would be my preferred. A simple time delay circuit could also be used instead of a time delay relay.
How difficult will it be to design such a circuit? I agree, I like the idea of reset when ignition is turned off.

        [Image: 20160929_171923_edit2_small.jpg]

1971 M-Code Mach 1 w/Ram Air, 408 stroker, 285/291 0.558" roller cam, Blue Thunder intake, TKO600, Hooker headers with electric cut-offs, FiTech EFI w/ RobBMC PowerSurge pump
Strange center section with Truetrac, 3.5 gear and 31 spline axles, 4-wheel disc brakes
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#37
Very easy, miniature single pole double throw relays could be used from the two brake switches. I haven't researched time delay relays, but I'm guessing they can be small also. The same for a latching relay, I believe they can be small also. It's been a while since I used either time delay or latching relays, and then they were for carrying large loads.

I believe I've seen latching relays for Arduino circuits, but they likely use 5 volt coils.



“If you can't explain it simply, you don't understand it well enough.”
--Albert Einstein
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#38
Another thought, by using the mechanical brake light switch and a pressure switch, only a failure in the brake circuit (front or rear) that the pressure switch is connected to would trigger the warning light.



“If you can't explain it simply, you don't understand it well enough.”
--Albert Einstein
  Reply
#39
(07-02-2019, 10:48 PM)Don C Wrote: Another thought, by using the mechanical brake light switch and a pressure switch, only a failure in the brake circuit (front or rear) that the pressure switch is connected to would trigger the warning light.
 Yeah, good point. In these combination valves the pressure switch is in the front circuit, which technically speaking is the most important. I still would like to have an warning when the fluid level is low because it is not easy to remove the cover of the Wilwood MC. I wish it had a window or indicator.

        [Image: 20160929_171923_edit2_small.jpg]

1971 M-Code Mach 1 w/Ram Air, 408 stroker, 285/291 0.558" roller cam, Blue Thunder intake, TKO600, Hooker headers with electric cut-offs, FiTech EFI w/ RobBMC PowerSurge pump
Strange center section with Truetrac, 3.5 gear and 31 spline axles, 4-wheel disc brakes
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#40
(07-02-2019, 07:05 PM)midlife Wrote:
(07-02-2019, 07:00 PM)Stanglover Wrote:   I'll post what I do later, but in the mean time, I'm all 'ears' for other ideas.
Geoff.
Oh, my MIL will take care of your ears.  She's very good at biting them off every moment she gets....

She's still available if anyone is interested.
 You crack me up!!
And no, I don't need yours, got one of my own.

I learn something new every day!
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