Air Flow Detector


Author Views Views Today Rank Comments
39,469 2 39
This simple circuit uses an incandescent lamp to detect airflow. With the filament exposed to air, a constant current source is used to slightly heat the filament. As it is heated, the resistance increases. As air flows over the filament it cools down, thus lowering it's resistance. A comparator is used to detect this difference and light an LED. With a few changes, the circuit can be connected to a meter or ADC to provide an estimation on the amount of air flow.

Schematic

Schematic for air flow detector

Parts

Part
Total Qty.
Description
Substitutions
R11100 Ohm 1/4W Resistor
R21470 Ohm 1/4W Resistor
R3110k 1/4W Resistor
R41100K 1/4W Resistor
R511K 1/4W Resistor
C1147uF Electrolytic Capacitor
U1178L05 Voltage Regulator
U21LM339 Op Amp
L11#47 Incandescent lamp with glass removed (See "Notes")
D11LED
MISC1Board, Wire, Sockets for ICs, etc.

Notes

  1. The glass will have to be removed from L1 without breaking the filament. Wrap the glass in masking tape and it in a vise. Slowly crank down until the glass breaks, then remove the bulb and carefully peel back the tape. If the filament has broken, you will need another lamp.

Related Circuits

Air Flow Detector, Wire Loop Alarm, Simple Two Speed Contactor DC Motor Controller , 7 Segment LED Counter, Simple Lie Detector, Low Voltage Alarm, Video Stabilizer/MacroVision Removal, Pulse Width Modulation DC Motor Control, Simple Polarity Tester, Pine Racecar Victory Judge, Rain Detector, Time Delay Relay, Time Delay Relay II, Stepper Motor Controller, Touch Switch, Video Activated Relay, Digital Keypad Combination Lock, AC Motor Speed Controller, Simple Servo Controller, Water Detector With Sump/Bilge Pump Controller

Comments

anonymous
Air Flow Detector
Thursday, April 10, 2008 5:30:16 AM
i think it will not work properly
anonymous
Air Flow Detector
Wednesday, March 12, 2008 7:44:29 PM
Can some one tell me about R4?... is it a varible resistor or a fixed resistor??.... I have built this circuit many of times but have not been able to get it to work..... Can anyone give me some feedback...thanks!!
vimal raj d
Air Flow Detector
Saturday, March 01, 2008 12:15:10 PM
sir i am going to take this as my project of present semster can i have some more details about this???? plz plz plz
khairul
Air Flow Detector
Wednesday, February 20, 2008 6:29:22 PM
hi there. nice circuit. i have some problems regarding the Incandescent lamp. i would like to implement this circuit into the pspice program but i do have problem to place the incandescent lamp. may i know, if there is a part can replace the criteria of the incandescent lamp in pspice? thank you
Rohan
Air Flow Detector
Friday, February 15, 2008 10:57:47 AM
Sir i want to take this circiut as my annual project,so plz plz send me more details about this cct.
jair frassao
Air Flow Detector
Thursday, January 31, 2008 9:27:00 AM
Hello friends, I can make an alarm for the fan of the motor of a car. When for of ventilating the detector it had informed me.
Michael
Air Flow Detector
Friday, January 25, 2008 6:34:04 AM
I haven't built one yet but I will try next week and let you know how good it is. I will have to trace the bulb first and may take me some time.
anonymous
Air Flow Detector
Tuesday, January 01, 2008 10:38:22 PM
A practical use of this? This is how a Mass Airflow Sensor works in late model cars. The computer must know how much air is flowing into the intake manifold so the computer can keep the air/fuel mixture at 14.7:1 (at sea level). By keeping a voltage constant through a wire in the MAS, the current can be measured to determine the airflow.
Amit
Air Flow Detector
Thursday, November 15, 2007 1:25:45 AM
I would like to know the working of air flow detector and component description.
abdul basit
Air Flow Detector
Tuesday, November 06, 2007 3:25:50 PM
Hai . I am Baist . I am making aproject plz give me some other simple progect ,
The last 10 comments are currently shown. Show All Comments.

If you would like to leave a comment, you can do so using the form below. Comments can be things like suggestions, successes or failures, improvements, similar circuits, error reports, an answer to a previous commenter's question, or anything in between. However if you would like to ask a question it is suggested that you use the forum instead. The forum provides a more robust environment for discussion.

Important: If you post a technical question here, there is no guarantee it will be answered. All technical questions should be posted to the forum. The owner of this site generally does not answer questions in comments.

All comments are subject to approval before they are displayed here, so your comment will not appear immediately. This is done mainly to prevent spam and other abuse. If you wish to remain anonymous, simply enter "anonymous" for your name and/or email.

Name:
Email:
Subject:
Comments:
Anti Spam Code:
Please enter the exact text shown in the image above into the box below.
Browser cookies must be enabled to comment on circuits.

Privacy Policy

Back To Circuits Page | Mail Me | Search