Hall Effect Sensor Recommendation

Using Arduino General Electronics
1

I have been working with a generic, inexpensive water flow sensor that utilizes a hall effect sensor. Sensor works fine, but it is drawing too much current. I need to prototype a battery operated version, so I am looking to replace the sensor with a more energy efficient chip. But, I have very limited knowledge on the Hall Sensors.

MCU is Arduino Micro

Any recommendations on specific part numbers to look at as a replacement.

2

If we don't know what you are using, now, how can we recommend another sensor? Are you looking for an analog sensor or a digital sensor? How do you have this one wired. And finally how much current is too much current?
Paul

3

The sensor is imbedded in the sensor so I don't know unless I destroy the housing. I have another broken sensor that has a W130 chip/sensor. I am guessing all these cheap flow sensors have the same or similar part.

With the sensor, SD breakout board from Adafruit, and Arduino Micro, I get about 5 days of data before my 16000mAh battery pack dies. Since I can't turn off the sensor I need something that is much ore efficient so I can get more like 1 month of data.

I have included photos of the sensor and board for reference.

4

You can find them on AliExpress and similar vendors. In your case I would shop for one that has a read switch. I believe Red is +, Black is -, and Yellow is output probably open collector.

5

**@gilshultz **
With a spinning ring magnet wouldn't the reed switch always be closed since there is always a magnetic field present?

6

Reed switches have limited cycles, which might be an issue.

Searching for "low power Hall switch" quickly found: https://www.allegromicro.com/en/products/sense/switches-and-latches/micropower-switches-latches/aps11700-760,
and I'm sure other manufacturers have similar devices. Another good search term would be "micropower".

7

@MarkT
Thanks for the link... funny enough I had just stumbled on that link. Also found a some options from Melexis.
Couple of questions... I have almost no experience in component terminology and datasheets.

  • What am I looking for on the data sheets to tell me what the current draw will be (Supply Current?)
  • Will an "Omni-polar" component work if the original was "Bi-Polar"?
  • What considerations do I need to be aware of with respect to output/signal voltage? Is there a threshold the Atmega chips need to be able to register?
8
  1. Supply current it is.
  2. omni-polar responds to both polarities of magnetic flux.
  3. Hall switches output a logic signal direct. Just be sure not to get an analog Hall sensor.

Note than most Hall switches have open-collector output and thus need INPUT_PULLUP
pin mode.

9

I ordered this TMR1202 DataSheet, and the recommended 0.1 micro cap.

Data says it has "CMOS push-pull output"... thinking this means it does NOT require the pull up resistor???

Parts won't arrive for a week or so. But thanks for the help!

10

lexical43:
I ordered this [

Data says it has "CMOS push-pull output"... thinking this means it does NOT require the pull up resistor???
[/quote]
Correct.](http://www.farnell.com/datasheets/2814602.pdf)

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