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  #1  
Old 08-11-2008, 07:02 AM
varsity_villain varsity_villain is offline
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Default Hydrogen Gas Sensor Circuit

Hi all,
I wan to design an analog circuit which can detect the concentration of the hydrogen and display it in LCD. the idea of the circuit is, it will detect an input from a gas sensor and the input will be used to calculate the concentration of the gas and will show the output in LCD.
So i need to design the circuit where it can detect the input from sensor. I dnt know how to start design the circuit. Anyone can help on this?? Any suggested analog circuit diagram???

realy need ur help guyz....
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Old 08-11-2008, 09:14 AM
jpanhalt jpanhalt is offline
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Is the hydrogen mixed with other gases? Which gases? What concentrations of hydrogen do you need to detect? What pressures?

In other words, you need to give more information about the conditions in which it will be operating.

Have you done any search yourself for information? Commercial units are readily available. Here and here are just two of many found under "hydrogen detector."

Also, Wikipedia has a nice article on hydrogen detection.

What is your level of experience in electronics and microcontroller programming?

John
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Old 08-17-2008, 01:40 AM
kender kender is offline
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Quote:
Originally Posted by varsity_villain View Post
So i need to design the circuit where it can detect the input from sensor.
If you've identified the sensor, whose output you need to measure, could you post a link to its datasheet? To help you design a circuit, we need to know the sensor that you have.
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Last edited by kender; 09-03-2008 at 09:23 PM.
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Old 08-17-2008, 07:54 AM
kammenos kammenos is offline
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Sensor -> microcontroller -> LCD...

Simple answer for simple question. Please be more specific
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Old 09-03-2008, 06:02 PM
varsity_villain varsity_villain is offline
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The idea of the design is

sensor > analog circuit > lcd

analog circuit:
input > integrator stage > comparator stage > output

so i have to design the analog circuit with the idea given to me. the sensor should only detect hydrogen gas and send the input as voltage to analog circuit. since the sensor will be fabricated by another group so i dont know the datasheet of the sensor. Basically the sensor is fabricated using SnO2 material. So any suggestion on how i can start design the analog circuit???
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Old 09-03-2008, 07:12 PM
blocco a spirale blocco a spirale is offline
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You've got to know the specs of the sensor.

What output voltage range are we looking at? microvolts? Volts? offset? How does the output relate to the concentration of gas?
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Old 09-04-2008, 02:16 AM
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thingmaker3 thingmaker3 is offline
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Quote:
Originally Posted by varsity_villain View Post
since the sensor will be fabricated by another group so i dont know the datasheet of the sensor.
If you at least know the required range of your display, you can work on a display driver. Once the stats on the sensor are available, you can design the signal conditioner.

If you don't know the required range of the display, you'll be able to work on something else entirely until your other group can give you some numbers.
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Old 11-12-2008, 06:33 AM
varsity_villain varsity_villain is offline
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hi,
is there anyone can suggest any circuit that i can construct to test the concentration of the hydrogen?? so far i found a light integrator circuit as my reference. do u think i can use light integrator circuit diagram to construct hydrogen circuit???
after had discussion with the group who will fabricate the hydrogen sensor, they said the output which can be produce from sensor is in mvolt or micro volt. so they wan my analog circuit can amplify the output and determine the concentration.

how i can construct the circuit?? from my understanding, i think i can use op-amp 741 as integrator and as a comparator. i juz dont understand how i wan use the op-amp with other components to came out with the analog circuit.

from,
confused...

Last edited by varsity_villain; 11-12-2008 at 06:49 AM.
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Old 11-12-2008, 01:07 PM
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thingmaker3 thingmaker3 is offline
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The 741 is a relatively old amp. You may be disappointed with its performance.

If you want a dual supply op amp, consider the TL084. If you want a single supply op amp, consider the OPA377.

Many other choices are available as well.

This might be of help: http://www.allaboutcircuits.com/vol_3/chpt_8/index.html
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Old 11-15-2008, 01:52 PM
varsity_villain varsity_villain is offline
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ok, if i wan to construct the circuit i need a reference. can u suggest any circuit diagram or tutorial were i can learn to build the analog circuit. i dont know from where to start. any suggestion please?
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