air flow sensor - diy hot wire air flow circuit

how to make thermal mass airflow sensor

I've checked the airflow sensor in a ford escort. it has two wires very close to each other. are the one used as a reference?

application notes air flow sensors

wolf69 said:

you can use ultrasoud too. in case of hot hair flow the two-termistor mode is not precise.
bye

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I agree. I've done sth like that

air flow meter using thermistors

have a look at most modern car engine management systems

the under bonnet environment is one of the most hostile electronics will encounter other than military - very high temp Δ, high G, high alititude Δ, very high electrical noise.

most systems use hot wire or ultrasonic Air Flow Meters and are electrically very robust, accurate, and normally have signal conditioning for 8-16V supply and 0-5V output.

save yourself time and effort and get one from a scrap vehicle and adapt it for your flow rate

good ones to use are Hitachi, Ford (Hitachi Clone) or Bosch

Polymath

how does an air flow thermistor sensor work

Just a short remark.
Talking again about the heating type of sensor.
I had already seen types that just use a metalic pipe whee the gas or the liquid will be pssing.
Then there are3 windings outside the pipe, so that there is really no contact beteewn the "sensor" and the material we are measuring the flux.
The measurementas are just the electrical resistances of the first and the third winding.
The first winding measures the temperature of the gas o liquid before it is heated up.
The second winding is used to warm up the fluid.
The 3rd winding measures the temperature of the fluid after is was warmed up by the 2nd winding.
Using a whitstone bridge the resistances of the first and 3rd windongs are compared and the mass flouw is related to the temperature difference of the 2 sensosrs (1st and 3rd).
It is a completely non invasive method that can be used to measure mass flow of "aggressiv" fluid for examples.

Hope it helps.
S.

air flow sensor circuit

kib said:

also this one
**broken link removed**

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It was late but can You tell me what was on this link ?
Some alternative to see information from link?

Thanks!

pic air flow sensor

I think, self-heating transistors are used more often than thermistors. Typically transistors with "metal can" case are used because they have better heat transfer. There are quite a few articles on this subject on the web. Here’s a couple:

https://www.edn.com/archives/1996/031496/06di3.htm
**broken link removed**

thermistor air flow application notes

kender said:

I think, self-heating transistors are used more often than thermistors. Typically transistors with "metal can" case are used because they have better heat transfer. There are quite a few articles on this subject on the web. Here’s a couple:

https://www.edn.com/archives/1996/031496/06di3.htm
**broken link removed**

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Tell me wich one You suggest to use ? TMP12 no more present .. Lm335 are one solution but in plastic case ...

Thanks for links!

air flouw tech

Diksi said:

kender said:

I think, self-heating transistors are used more often than thermistors. Typically transistors with "metal can" case are used because they have better heat transfer. There are quite a few articles on this subject on the web. Here’s a couple:

https://www.edn.com/archives/1996/031496/06di3.htm
**broken link removed**

Click to expand...

Tell me wich one You suggest to use ?

Click to expand...

I don't have a particulal preference. I would recomend implementing them with 2N2222 transistors in TO-18 (metal can) cases .

Diksi said:

Lm335 are one solution but in plastic case ...

Click to expand...

LM335 is available in TO-46 case, which is a type of metal can.

air flow switch using thermistor

hi

this is another good idea using discrate component



regards
Fragrance

air flow sensor installation method

The idea of this circuit is good, but the start-up self-adjustment takes long time, and the zero adjustment pot is not really easy. In a hurry, think again.

Re: AIR FLOW SENSOR

Hi

If any1 has made an air flow sensor/detecctor succesfuly plz give the circuit diagram as my circuits dint work...
thanks

Re: AIR FLOW SENSOR

Air Flow Sensor or Air Flow Meter? You're not working on a VW by some chance?