Digital pressure Gauge

[JJACALYPSO]

ok guys let me explain first, im not an electronics guy however im tired of paying so much money for gauges! to narrow things down I build mustangs and often install nitrous in them and the most efficent way to measure the pressure is with a pressure transducer and a digital display.
so my questions are to anyone that is willing to help me can i buy a transducer, 3 wires are what ive typically seen? and how would i tie that into a dispaly? this cant be difficult ahaha however i do not want to throw money into 10 displays because i wire them wrong..

ill take any imput or direction i can get thanks a lot guys and aplace to buy parts

 

[Inquisitive]

Firstly this is an international website. "a place to buy parts" can vary in cost depending on shipping costs and time and patience. If you don't mind the wait. It can take weeks. Are you a resident of Europe, Asia, UK or North America, Australia? See the issue here?

 

[JJACALYPSO]

north america

 

[cowboybob]

ok guys let me explain first, im not an electronics guy however im tired of paying so much money for gauges! to narrow things down I build mustangs and often install nitrous in them and the most efficent way to measure the pressure is with a pressure transducer and a digital display.
so my questions are to anyone that is willing to help me can i buy a transducer, 3 wires are what ive typically seen? and how would i tie that into a dispaly? this cant be difficult ahaha however i do not want to throw money into 10 displays because i wire them wrong..

ill take any imput or direction i can get thanks a lot guys and aplace to buy parts

Is this for monitoring the Nitrous tank pressure or the delivery pressure?

If delivery:

https://www.glowshiftdirect.com/elite-10-color-1600psi-Nitrous-Pressure-Gauge.aspx

Not cheap, but all calibrated and plug and play...

 

[KeepItSimpleStupid]

Or even boost pressure?

Of somewhat importance, the range and units expected and to what resolution. Is this gauge or absolute pressure?

I hate units of Pascals and the units of atmospheres is just as weird. My boss used to say, numbers between 1 and 10; 100,000 Pascals doesn't cut it.

The environment makes a difference as well.

A lot of the automotive sensors are what you call ratiometric. This is a fancy word where the power supply or a fraction of the power supply is 100% of full scale. This reference can vary.

A 0-5 output thus can be much different than a ratiometric 0-5 V output.

While searching the net recently, I ran into a firm that build displays and indicators into the mirror. www.radar-mirror.com

 

[JJACALYPSO]

The pressure is tank pressure with optimal pressure being 1050 psi. i ran a gauge from dynotune nitrous the thing seemed so easy to make as he did it in less than ten minutes it was a simple square digital display screen with pressure transducer at the other end..

gauge- nitrous pressure - DynoTune

 

[JJACALYPSO]

keepitsimple---- them mirrors are awesome that might be an awesome place to put it!!!

 

[KeepItSimpleStupid]

I though they were "cool" too. I just sent a mirror for repair, although I did not use them. Word has it that 14 YO mirrors are beyond their expected lifetime and it has to do with the seal. So, any recycled part is going to have a lifetime issue. The mirrors apparently "snap open", but you risk damaging the plastics. My mirror also has connector issues.

The mirror I replaced was very difficult to get off and the factory service manual instructions were not much better. It's best to use a Windshield repair company if removal proves difficult.

 

[KeepItSimpleStupid]

That's the real problem. No one is telling you the specs. The mirror guys aren't and the pressure transducer people aren't.

In any event, here **broken link removed** is a pressure transducer, but it's WAY more expensive that Dynotune. Hopefully you can get Dynotune to send you specs of the transducer and get the mirror guys to tell you some of the inputs they can accept.

0-5 ratiometric is probably a "good input". zero can never be achieved and neither can 5V. So, you get something like 0.6 to whatever the power supply is minus a bit. so, at exactly 5V, the output may be 0.1, but if the sullpy was 5.1 V, the output would be different.

You also have the engineering units thing to deal with, If the thing only displayed 199.0 full scale, then you have to pick a gain and an offset to read 0-1999 PSI, for instance.

Because 0V and 5V are not obtainable with a 5V supply, ratiometric is good. You can get close to 0V and close to 5V, but generally it's very difficult to read a voltage close to the power supply rails.

It's really easy to get a uP to read a ratiometric signal.

So, I can see the probem, but not the solution when neither manufacturer talks to you.

 

[KeepItSimpleStupid]

FYI:

Here https://www.google.com/url?sa=t&rct...wE7X3d8OesxoiCg&bvm=bv.76247554,d.cWc&cad=rja is a circuit that converts a ratiometric output to a ground referenced output for, a low output pressure sensor, no less.

 

[JJACALYPSO]

thanks a lot this has got my gears turning!! hopfully get some progress on it this weekend

 

[KeepItSimpleStupid]

At least the PLX guage system that RM supports has somewhat of a manual. See, this https://www.plxdevices.com/support/manuals/M-300TEUsersGuide.pdf for example. Note that there is an offset at zero and it doesn't quite output 5 V.

So, one might expect that RM has to match the signal to engineering units.

So, my questions would be to RM:
1) Can you accept single-ended or differential, or ratiometric inputs?
2) If you assume that the signal is from 0-5V, what is the max value you can represent without a decimal point. e.g. 1999, 3999 etc. Even 0-200 mV can only display 000 to 199
3. Is the decimal place fixed or variable?
4) What is the input impedance.
5) What has to be provided to you for a totally custom range?
6) Are units displayed. Is PSI available, Is 0-1000 or whatever PSI available etc.