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Which Oil Pressure Switch?
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Mudfly

Joined: 04 Feb 2012
Posts: 39

Posted: Wed Apr 26, 2023 3:54 pm Post subject: Re: Which Oil Pressure Switch?

Will do Bob.  I'll try and  get that set up tomorrow and post what I find.

Thanks.

Shawn



Shawn,



   Could you set this hourmeter up on the bench

   and measure the current draw on the enable

   pin in the pull-up configuration? I think

   I have a simple solution using p-lead

   signal from a mag to drive the enable pin

   but having that current value would facilitate

   optimization of the components.



 

   Bob . . .



                    //// 

                   (o o) 

    ===========o00o=(_)=o00o========= 

    <Go> 

    < show me where I'm wrong.      > 

    =================================

  

    In the interest of creative evolution

    of the-best-we-know-how-to-do based

    on physics and good practice.[/quote]

argoldman(at)aol.com
Guest

Posted: Wed Apr 26, 2023 5:27 pm Post subject: Which Oil Pressure Switch?

Whatever you choose for a transducer for any liquid pressure, make sure you install a restrictor in line to prevent major fluid loss in case of physical sensor leakage or breakage. 

Sent from my iPhone



 	  Quote: 	
		   On Apr 26, 2023, at 6:54 PM, Mudfly <shawntedwards(at)hotmail.com> wrote:

 

 ï»¿

 

 Will do Bob.  I'll try and  get that set up tomorrow and post what I find.

 Thanks.

 Shawn

 

 

 

 Shawn,

 

   Could you set this hourmeter up on the bench

   and measure the current draw on the enable

   pin in the pull-up configuration? I think

   I have a simple solution using p-lead

   signal from a mag to drive the enable pin

   but having that current value would facilitate

   optimization of the components.

 

 

   Bob . . .

 

                    //// 

                   (o o) 

    ===========o00o=(_)=o00o========= 

 

    < show me where I'm wrong.      > 

    =================================

 

    In the interest of creative evolution

    of the-best-we-know-how-to-do based

    on physics and good practice. 	


 

 

 

 

 Read this topic online here:

 

 http://forums.matronics.com/viewtopic.php?p=510710#510710

 

 

 

 

 

 

 

 

 


[/quote]

Mudfly

Joined: 04 Feb 2012
Posts: 39

Posted: Thu Apr 27, 2023 4:41 pm Post subject: Re: Which Oil Pressure Switch?

Ok Bob here's what I did to check the hourmeter.

I connected a power supply to the positive and negative pins on the 

hourmeter.   This illuminated the LCD digits but elapsed time was not recorded.   I then added the enable pin to the positive lead from 

the power supply and elapsed time began recording.  

Unfortunately, I was unable to measure any current draw with the

equipment I have.    Probably too low I guess?

The placard on the hourmeter says 1/2W max.   

Anything else I can do?  

I took a video but didn't turn out too good.   Attached a pic of my power supply.   

Thanks,

Shawn 



[quote="nuckolls.bob(at)aeroelect"]--> AeroElectric-List message posted by: "Mudfly" <shawntedwards>



 [quote="nuckolls.bob(at)aeroelect"]At 07:56 AM 4/21/2023, you wrote:

  [quote]--> AeroElectric-List message posted by: "Mudfly" 



 

   Shawn,



   Could you set this hourmeter up on the bench

   and measure the current draw on the enable

   pin in the pull-up configuration? I think

   I have a simple solution using p-lead

   signal from a mag to drive the enable pin

   but having that current value would facilitate

   optimization of the components.



 

   Bob . . .



                    //// 

                   (o o) 

    ===========o00o=(_)=o00o========= 

    <Go> 

    < show me where I'm wrong.      > 

    =================================

  

    In the interest of creative evolution

    of the-best-we-know-how-to-do based

    on physics and good practice.[/quote]

thumbnail_IMG_3713.jpg

Description:

Here's my power supply.

Filesize:

30.4 KB

Viewed:

5167 Time(s)

nuckolls.bob(at)aeroelect
Guest

Posted: Sun Apr 30, 2023 6:56 am Post subject: Which Oil Pressure Switch?

At 07:41 PM 4/27/2023, you wrote:

  	  Quote: 	
		  --> AeroElectric-List message posted by: "Mudfly" <shawntedwards(at)hotmail.com>



 Ok Bob here's what I did to check the hourmeter.

 I connected a power supply to the positive and negative pins on the 

 hourmeter.   This illuminated the LCD digits but elapsed time was not recorded.   I then added the enable pin to the positive lead from 

 the power supply and elapsed time began recording.  

 Unfortunately, I was unable to measure any current draw with the

 equipment I have.    Probably too low I guess?

 The placard on the hourmeter says 1/2W max.   

 Anything else I can do?   	


    No, I've got an approach in mind. Let

    me rummage around in the 'junk box'.



 

 

   Bob . . .



                    //// 

                   (o o) 

    ===========o00o=(_)=o00o========= 

    < Go ahead, make my day . . .   > 

    < show me where I'm wrong.      > 

    =================================

  

    In the interest of creative evolution

    of the-best-we-know-how-to-do based

    on physics and good practice.

nuckolls.bob(at)aeroelect
Guest

Posted: Tue May 02, 2023 1:35 pm Post subject: Which Oil Pressure Switch?

No, I've got an approach in mind. Let

    me rummage around in the 'junk box'.



    Got all the parts I need but one . . .

    piggybacked it onto an order for

    another project. I'll be able

    to provide you a plug-n-play

    adapter to trigger your hour-meter

    using the p-lead signal off

    your mag.



 

 

   Bob . . .



                    //// 

                   (o o) 

    ===========o00o=(_)=o00o========= 

    < Go ahead, make my day . . .   > 

    < show me where I'm wrong.      > 

    =================================

  

    In the interest of creative evolution

    of the-best-we-know-how-to-do based

    on physics and good practice.

Mudfly

Joined: 04 Feb 2012
Posts: 39

Posted: Mon May 08, 2023 5:38 am Post subject: Re: Which Oil Pressure Switch?

Not sure if this is relative to my Hobbs meter "Enable" situation or

or not.   I haven't had a chance to do my homework yet.   

I will be using a SureFly  and a Slick mag for my ignition setup.  I discovered

the Surefly will not provide RPM output to the G3X system when the 

Slickmag  is switched off or inop.    Surefly does have a Tach signal 

converter that will solve this issue but, from what I understand, the 

UMA T1A9-1 (see attachment below) will also solve the issue.   

Again, I haven't had a chance to research the UMA T1A9 information yet but 

wanted to bring this up in case it may be useful to my hobbs meter enable

function.     

Thanks,

Shawn

mag-pickup-wires.pdf

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Download

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mag-pickup-wires.pdf

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nuckolls.bob(at)aeroelect
Guest

Posted: Mon May 08, 2023 8:11 am Post subject: Which Oil Pressure Switch?

At 08:38 AM 5/8/2023, you wrote:

  	  Quote: 	
		  --> AeroElectric-List message posted by: "Mudfly" <shawntedwards(at)hotmail.com>



 Not sure if this is relative to my Hobbs meter "Enable" situation or

 or not.   I haven't had a chance to do my homework yet.   

 I will be using a SureFly  and a Slick mag for my ignition setup.  I discovered

 the Surefly will not provide RPM output to the G3X system when the 

 Slickmag  is switched off or inop. 	


   Hmmm . . . how does the SureFly know anything

   about the magneto condition?



  	  Quote: 	
		  Surefly does have a Tach signal 

 converter that will solve this issue but, from what I understand, the 

 UMA T1A9-1 (see attachment below) will also solve the issue. 	


   This is a powered, hall-effect sensor that

   watches the magneto's magnet thus providing

   a nice, clean square wave signal 

   completely independent of the magneto's

   operating condition. 

  	  Quote: 	
		     

 Again, I haven't had a chance to research the UMA T1A9 information yet but 

 wanted to bring this up in case it may be useful to my hobbs meter enable

 function.     	


   Yes, it WOULD provide a signal compatible with

   the proposed hour-meter enable interface. Unlike

   my original idea, the hour-meter would continue

   to run whether or not the magneto was 'active'.



   It's a lot more expensive. My proposed interface

   looks at the p-lead noise of a active magneto.

   Of course, it the mag is "off", the hour meter

   doesn't run. Errors for recording engine run time

   should be very small to non existent . . . how

   often and for how long would you plan to fly with

   the magneto off?



   Either way works. But I'm mystified as to why

   the SureFly would depend on Slick operations

   to provide a tach signal . . . 



 

   Bob . . .



                    //// 

                   (o o) 

    ===========o00o=(_)=o00o========= 

    < Go ahead, make my day . . .   > 

    < show me where I'm wrong.      > 

    =================================

  

    In the interest of creative evolution

    of the-best-we-know-how-to-do based

    on physics and good practice.

Ceengland

Joined: 11 Oct 2020
Posts: 391
Location: MS

Posted: Mon May 08, 2023 8:43 am Post subject: Which Oil Pressure Switch?

 	  Quote: 	
		  



 Â  Either way works. But I'm mystified as to why

 Â  the SureFly would depend on Slick operations

 Â  to provide a tach signal . . . 



 

 Â  Bob . . .



	
I suspect that what he's saying is that the Surefly doesn't output a tach signal usable in the same fashion as the mag p-lead signal. Therefore, there's no signal to any electronic tach if the mag is off. Pretty common situation with aftermarket electronic ignitions for Lycs.Â

_________________
Charlie

Mudfly

Joined: 04 Feb 2012
Posts: 39

Posted: Mon May 08, 2023 9:26 am Post subject: Re: Which Oil Pressure Switch?

Â Either way works. But I'm mystified as to why

 Â  the SureFly would depend on Slick operations

 Â  to provide a tach signal . . . 

 Bob . 



I suspect that what he's saying is that the Surefly doesn't output a tach signal usable in the same fashion as the mag p-lead signal. Therefore, there's no signal to any electronic tach if the mag is off. Pretty common situation with aftermarket electronic ignitions for Lycs.

Charlie .



Yes Charlie.   The Surefly doesn't output a usable tach signal to the G3X.   So, during mag chk on run-ups, the rpm drops to zero when slick mag is selected off.   Some don't mind this and just listen for RPM drop.  Definitely the most simple approach.   I just like to make things difficult so I looked at options to still have RPM visible.   It appeared the SureFly Tach sensor

and the UMA T1A9-1 were the popular options.  I went with the T1A9-1.

Shawn .



Bob,  

I purchased the T1A9-1 solely for the RPM function.   It wasn't until I reviewed the documentation that I saw the "voltage out to hourmeter" 

statement shown on pg2 of the document attached in my previous post.

Like you mentioned, I only want the hourmeter to record time when

the engine is running.  Sounds like your method will accomplish that.



Thanks.

Shawn

nuckolls.bob(at)aeroelect
Guest

Posted: Fri May 19, 2023 7:09 am Post subject: Which Oil Pressure Switch?

At 11:43 AM 5/8/2023, you wrote:



    Been out-of-pocket for a few days . . . returning

    to the 'oil pressure switch thread' . . .



  	  Quote: 	
		    Â  Either way works. But I'm mystified as to why Â  the SureFly would depend on Slick operations Â  to provide a tach signal . . . 

  Â  Bob . . .



 I suspect that what he's saying is that the Surefly doesn't output a tach signal usable in the same fashion as the mag p-lead signal. Therefore, there's no signal to any electronic tach if the mag is off. Pretty common situation with aftermarket electronic ignitions for Lycs. 	




   Aha! but of course. Given that a hall-effect

   tach pickup has been added to the conversation,

   making that signal activate the hour-meter as

   well is easy. Of course, there's a further

   benefit that the tach/hour-meter functions

   are independent of conditions of either

   ignition system.



   I've sketched out an adapter circuit that would

   interface the square wave output of your tachometer

   pickup to the hour-meter.



   The suggested transistor is hugely 'too-robust'

   for the task but it's in a large package that

   yields to 'spider-web' assembly of the components

   directly to the transistor case before protecting

   in some suitable encapsulant (E6000, JB Kwik, etc.)



   Alternatively, this could be assembled on some

   form of prototyping board in which case, ANY

   logic level n-fet would be find.



   If you wish, I can hammer this together out

   of my junkbox. It would be fitted with flying

   leads for interposition between your tach and

   hour-meter.



 



 

   Bob . . .



                    //// 

                   (o o) 

    ===========o00o=(_)=o00o========= 

    < Go ahead, make my day . . .   > 

    < show me where I'm wrong.      > 

    =================================

  

    In the interest of creative evolution

    of the-best-we-know-how-to-do based

    on physics and good practice.

Taco-HrMeter_Signal_Conditioner.pdf

Description:

Download

Filename:

Taco-HrMeter_Signal_Conditioner.pdf

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Mudfly

Joined: 04 Feb 2012
Posts: 39

Posted: Sat May 20, 2023 1:30 pm Post subject: Re: Which Oil Pressure Switch?

Thanks Bob.

Sounds like your plan is exactly what I'm looking for. Not sure I fully understand what's going on though. 

You lost me at "I've sketched out an adapter circuit that would interface the square wave output of your

tachometer pickup to the hour-meter."  I can follow the diagrams basic

wiring, but still need some time in a dark corner to figure out the rest.

Slightly above my elctronical knowledge level.

I would happily accept/appreciate whatever you could come up with out of

your junkbox. Surely we can do some type of horse-trading to make it

worth your while.

Thanks again,

Shawn

nuckolls.bob(at)aeroelect
Guest

Posted: Mon May 22, 2023 7:11 am Post subject: Which Oil Pressure Switch?

At 04:30 PM 5/20/2023, you wrote:

  	  Quote: 	
		  --> AeroElectric-List message posted by: "Mudfly" <shawntedwards(at)hotmail.com>



 Thanks Bob.

 Sounds like your plan is exactly what I'm looking for. Not sure I fully understand what's going on though. 

 You lost me at "I've sketched out an adapter circuit that would interface the square wave output of your

 tachometer pickup to the hour-meter."  I can follow the diagrams basic

 wiring, but still need some time in a dark corner to figure out the rest.

 Slightly above my elctronical knowledge level.

 I would happily accept/appreciate whatever you could come up with out of

 your junkbox. Surely we can do some type of horse-trading to make it

 worth your while.

 Thanks again,

 Shawn 	


     Very well sir. I'm mindful of the fact that

     this forum is populated with a diversity

     of experience and skills. It was not my wish

     that you grasp the gritty details of my

     proposal. But publishing the 'details' 

     affords opportunity for those interested

     and willing to add the them to their

     personal bag of tricks.



     I'll scrape off a bit of space on the

     workbench and hammer this thing together.



 

 

   Bob . . .



                    //// 

                   (o o) 

    ===========o00o=(_)=o00o========= 

    < Go ahead, make my day . . .   > 

    < show me where I'm wrong.      > 

    =================================

  

    In the interest of creative evolution

    of the-best-we-know-how-to-do based

    on physics and good practice.

Mudfly

Joined: 04 Feb 2012
Posts: 39

Posted: Wed Jun 28, 2023 11:00 am Post subject: Re: Which Oil Pressure Switch?

I've been off this topic for a while because I decided to install gear and 

engine on my project.    As always more new stuff to learn.   Bob, let me 

if you've had any luck with that adaptor circuit for the hobbs meter.   

I hope to get back in the electrical game in a couple weeks.

Shawn

nuckolls.bob(at)aeroelect
Guest

Posted: Fri Jun 30, 2023 3:22 pm Post subject: Which Oil Pressure Switch?

At 02:00 PM 6/28/2023, you wrote:

  	  Quote: 	
		  --> AeroElectric-List message posted by: "Mudfly" <shawntedwards(at)hotmail.com>



 I've been off this topic for a while because I decided to install gear and 

 engine on my project.    As always more new stuff to learn.   Bob, let me 

 if you've had any luck with that adaptor circuit for the hobbs meter.   

 I hope to get back in the electrical game in a couple weeks. 	


   Yes. I've been 'out of pocket' for a bit.

   Just delivered a batch of camera door actuator

   controllers to a old customer that surprised

   me with an order.



   Cleaning up my temporary 'production

   line' off the dinning room table!

   I can get to the adapter after this

   weekend.



 

 

   Bob . . .



                    //// 

                   (o o) 

    ===========o00o=(_)=o00o========= 

    < Go ahead, make my day . . .   > 

    < show me where I'm wrong.      > 

    =================================

  

    In the interest of creative evolution

    of the-best-we-know-how-to-do based

    on physics and good practice.

Mudfly

Joined: 04 Feb 2012
Posts: 39

Posted: Tue Mar 26, 2024 5:23 am Post subject: Re: Which Oil Pressure Switch?

I've been away from electrical work on my project while I installed 

engine and related accessories.   

I'm reviving this thread on ways to activate a hobbs meter without 

using an oil pressure switch.  I have an LED hobbs meter that I would

like to wire so that it will display the hours when the batt switch is on , 

but not count time.   I would like the timer to begin when engine is started.

As a review from the previous threads above, I have a 3-terminal 

hobbs (+, -, and Enable).    The positive terminal is fed from the Main Power Bus when batt is switched, and negative to firewall ground bus. The LED 

digits illuminate with Batt switch on.   I now need a way to power the

Enable terminal to begin the timer.   

I have an idea but not sure of the part I need or if it even exists.

Here the plan.  The positive terminal will have the 12v input from the main power bus.  Also, I will have a feed wire from the positive terminal to 

the "Unknown Device".   The wire will continue from the unknown 

device to the Enable pin on the hobbs meter.    The "Unknown Device" 

will need to block power until volts are above batt voltage..

say 13V??.   When the engine is started and alternator is switched on, 

power will pass the unknown device and power the enable terminal of the 

hobbs meter.    

Does this "Unknown Device" exist, and does the plan seem feasible?

Links to PDF drawings of a simple wire diagram and also tech sheet of the 

Honeywell LCD Hour meter.

Thanks for the help.

Shawn

Honeywell LCD Hour Meter.pdf

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kenryan

Joined: 20 Oct 2009
Posts: 426

Posted: Tue Mar 26, 2024 7:34 am Post subject: Which Oil Pressure Switch?

I have a battery charger that senses vibration caused when the engine is started, and uses that as a trigger. I wouldn't have any idea how to procure or implement a vibration sensor as a trigger for your Hobbs, but I'll bet some of the guys on this list do.



On Tue, Mar 26, 2024 at 5:28â€¯AM Mudfly <shawntedwards(at)hotmail.com (shawntedwards(at)hotmail.com)> wrote:



 	  Quote: 	
		  --> AeroElectric-List message posted by: "Mudfly" <shawntedwards(at)hotmail.com (shawntedwards(at)hotmail.com)>

 

 I've been away from electrical work on my project while I installed 

 engine and related accessories.Â  Â 

 I'm reviving this thread on ways to activate a hobbs meter without 

 using an oil pressure switch.Â  I have an LED hobbs meter that I would

 like to wire so that it will display the hours when the batt switch is on , 

 but not count time.Â  Â I would like the timer to begin when engine is started.

 As a review from the previous threads above, I have a 3-terminal 

 hobbs (+, -, and Enable).Â  Â  The positive terminal is fed from the Main Power Bus when batt is switched, and negative to firewall ground bus. The LED 

 digits illuminate with Batt switch on.Â  Â I now need a way to power the

 Enable terminal to begin the timer.Â  Â 

 I have an idea but not sure of the part I need or if it even exists.

 Here the plan.Â  The positive terminal will have the 12v input from the main power bus.Â  Also, I will have a feed wire from the positive terminal to 

 the "Unknown Device".Â  Â The wire will continue from the unknown 

 device to the Enable pin on the hobbs meter.Â  Â  The "Unknown Device" 

 will need to block power until volts are above batt voltage..

 say 13V??.Â  Â When the engine is started and alternator is switched on, 

 power will pass the unknown device and power the enable terminal of the 

 hobbs meter.Â  Â  

 Does this "Unknown Device" exist, and does the plan seem feasible?

 Links to PDF drawings of a simple wire diagram and also tech sheet of the 

 Honeywell LCD Hour meter.

 Thanks for the help.

 Shawn

 

 

 

 

 Read this topic online here:

 

 http://forums.matronics.com/viewtopic.php?p=513410#513410

 

 

 

 

 Attachments: 

 

 http://forums.matronics.com//files/honeywell_lcd_hour_meter_173.pdf

 http://forums.matronics.com//files/hobbs_meter_117.pdf

 

 

 

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Ceengland

Joined: 11 Oct 2020
Posts: 391
Location: MS

Posted: Tue Mar 26, 2024 8:17 am Post subject: Which Oil Pressure Switch?

On Tue, Mar 26, 2024 at 8:28â€¯AM Mudfly <shawntedwards(at)hotmail.com (shawntedwards(at)hotmail.com)> wrote:



 	  Quote: 	
		  --> AeroElectric-List message posted by: "Mudfly" <shawntedwards(at)hotmail.com (shawntedwards(at)hotmail.com)>

 

 I've been away from electrical work on my project while I installed 

 engine and related accessories.Â  Â 

 I'm reviving this thread on ways to activate a hobbs meter without 

 using an oil pressure switch.Â  I have an LED hobbs meter that I would

 like to wire so that it will display the hours when the batt switch is on , 

 but not count time.Â  Â I would like the timer to begin when engine is started.

 As a review from the previous threads above, I have a 3-terminal 

 hobbs (+, -, and Enable).Â  Â  The positive terminal is fed from the Main Power Bus when batt is switched, and negative to firewall ground bus. The LED 

 digits illuminate with Batt switch on.Â  Â I now need a way to power the

 Enable terminal to begin the timer.Â  Â 

 I have an idea but not sure of the part I need or if it even exists.

 Here the plan.Â  The positive terminal will have the 12v input from the main power bus.Â  Also, I will have a feed wire from the positive terminal to 

 the "Unknown Device".Â  Â The wire will continue from the unknown 

 device to the Enable pin on the hobbs meter.Â  Â  The "Unknown Device" 

 will need to block power until volts are above batt voltage..

 say 13V??.Â  Â When the engine is started and alternator is switched on, 

 power will pass the unknown device and power the enable terminal of the 

 hobbs meter.Â  Â  

 Does this "Unknown Device" exist, and does the plan seem feasible?

 Links to PDF drawings of a simple wire diagram and also tech sheet of the 

 Honeywell LCD Hour meter.

 Thanks for the help.

 Shawn

 

	
1st thing that comes to mind is a comparator circuit.Â It looks at two inputs, and outputs when the trigger input exceeds the reference input. If you set the reference input to 13V using a voltage regulator, then the trigger input would go above that when the alternator comes on line. Potential downside is that the Hobbs will stop counting if the alternator fails.

If you don't know about it, a 'Tiny Tach' works in a similar manner but has an internal battery. The sense lead is normally wrapped around a spark plug lead; won't work with shielded leads. But you can make it work with a slight mod to the distributor cap on a mag.

Charlie



Virus-free.www.avast.com[url=#DAB4FAD8-2DD7-40BB-A1B8-4E2AA1F9FDF2][/url]

_________________
Charlie

mike_tailwind

Joined: 06 Feb 2017
Posts: 12

Posted: Tue Mar 26, 2024 8:26 am Post subject: Which Oil Pressure Switch?

You could modify Bob's latest overvoltage module to do what you need.  Change the trip point to 13.5 volts, and remove the SCR.

From schematic 9003-630-IP6:

Change R7 from 13.7K to 11K

Remove Q15

Add a wire from U11B pin 7 to the enable input  of the hour meter.

What we don't know is how much current the enable input to the hour meter draws.  To test, place a 2.49K resistor between the enable input of the hourmeter and 12Volts.  If it starts counting, no additional changes to the OVM need to be made.  

                  

                                                                        On Tuesday, March 26, 2024 at 08:34:33 AM CDT, Mudfly <shawntedwards(at)hotmail.com> wrote:                     

                     



                     



                                                   --> AeroElectric-List message posted by: "Mudfly" <shawntedwards(at)hotmail.com (shawntedwards(at)hotmail.com)>



I've been away from electrical work on my project while I installed 



engine and related accessories.   



I'm reviving this thread on ways to activate a hobbs meter without 



using an oil pressure switch.  I have an LED hobbs meter that I would



like to wire so that it will display the hours when the batt switch is on , 



but not count time.   I would like the timer to begin when engine is started.



As a review from the previous threads above, I have a 3-terminal 



hobbs (+, -, and Enable).    The positive terminal is fed from the Main Power Bus when batt is switched, and negative to firewall ground bus. The LED 



digits illuminate with Batt switch on.   I now need a way to power the



Enable terminal to begin the timer.   



I have an idea but not sure of the part I need or if it even exists.



Here the plan.  The positive terminal will have the 12v input from the main power bus.  Also, I will have a feed wire from the positive terminal to 



the "Unknown Device".   The wire will continue from the unknown 



device to the Enable pin on the hobbs meter.    The "Unknown Device" 



will need to block power until volts are above batt voltage..



say 13V??.   When the engine is started and alternator is switched on, 



power will pass the unknown device and power the enable terminal of the 



hobbs meter.    



Does this "Unknown Device" exist, and does the plan seem feasible?



Links to PDF drawings of a simple wire diagram and also tech sheet of the 



Honeywell LCD Hour meter.



Thanks for the help.



Shawn



Read this topic online here:



http://forums.matronics.com/viewtopic.php?p=513410#513410



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Mudfly

Joined: 04 Feb 2012
Posts: 39

Posted: Tue Mar 26, 2024 9:55 am Post subject: Re: Which Oil Pressure Switch?

Thanks for the Ideas.

Kenryan,  I have seen the vibration activated hour meters.   Definitely

the most simple solution.   Unfortunately, I already have the Honeywell

installed in my panel and will try and make that work if I can.



Charlie, I will do some studying of the comparator circuit.   Looks like

it could work.



Mike, Thanks for the details on how to modify Bob's overvoltage module.

I haven't been able to locate schematic 9003-630-IP6 you mentioned.  I

will keep searching.



Shawn

user9253

Joined: 28 Mar 2008
Posts: 1925
Location: Riley TWP Michigan

Posted: Tue Mar 26, 2024 10:20 am Post subject: Voltage Controlled Switch

eBay item number:364742288098 might be the device that you are looking for.

Or maybe this one from Amazon:

https://www.amazon.com/XH-M609-Digital-Disconnect-Discharge-Protection/dp/B07WRZSJ5M

Instructions written in Chinlish:

https://www.robotics.org.za/XH-M609

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Joe Gores

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