do this without arduino

Forum 2005-2010 (read only) General Bar Sport
1

hi ,
i have a gas sensor (LPG) now i can interface this with arduino but i want to do it without it i guessed i could use SOMETHING :wink: such that it could measure the valuse of the sensor against a set value(might be by using a potentiometer) and activate a buzzer if the value from the sensor is more that the set value
and if the whole thing is powered sing a battery i guess the set value should be changes as the voltage drops how to counter this effect ?
the sensor returns varying resistance (analog)

2

I think the usual approach is to use a Wheatstone bridge and an op-amp

3

if the whole thing is powered sing a battery i guess the set value should be changes as the voltage drops how to counter this effect ?

Another common method is to generate a stable voltage source via a small regulator chip or zener diode and use that to supply to the pot that is adjusted to the desired 'setpoint' value to use.

Lefty

4

I think the usual approach is to use a Wheatstone bridge and an op-amp

thanks it cleared the SOMETHING which i wanted to use ill pop back when i get cleared as of how to do it :wink:

Another common method is to generate a stable voltage source via a small regulator chip or zener diode and use that to supply to the pot that is adjusted to the desired 'setpoint' value to use.

Thanks is it possible to shut down the whole thing when the battery deops below the Required voltage ?

5

Thanks is it possible to shut down the whole thing when the battery deops below the Required voltage ?

Correct me if I'm wrong, but I would think you would want the alarm to go off if the battery dies. Seems unsafe to have the gas monitor quietly deactivate. :stuck_out_tongue:

6

oh i forgot that whole thing :o
you wer right i wanted it to give out a buzz and light a battery low led and then shutdown having the batt low led gleaming :sunglasses: