TheBackShed.com

Forum Index : Microcontroller and PC projects : Counting Pulses

Author

Message

palcal

Guru

Joined: 12/10/2011
Location: Australia
Posts: 1993

Posted: 03:20am 19 Dec 2018

Copy link to clipboard

Print this post

I have a Hall Effect sensor on a rain gauge, the output is 3.3v and goes low when the magnet passes (ie when the bucket tips). I am having trouble counting the pulses. I have set pin 15 to CIN connected to the output pin, but when the bucket tips nothing happens. I can see on my meter that the pin is going low at each tip but it won't count.
Paul.

"It is better to be ignorant and ask a stupid question than to be plain Stupid and not ask at all"

TassyJim

Guru

Joined: 07/08/2011
Location: Australia
Posts: 6283

Posted: 04:05am 19 Dec 2018

Copy link to clipboard

Print this post

It should work.
I use all 4 counting pins 15 - 18 for counting hall effect flow meters.
I read the pins every 30 seconds without any issues.
You could try another pin - just in case, or try setting an interrupt to see if the 'mite is getting the change of level.

Jim

VK7JH
MMedit

palcal

Guru

Joined: 12/10/2011
Location: Australia
Posts: 1993

Posted: 04:06am 19 Dec 2018

Copy link to clipboard

Print this post

I tried using an Interrupt with limited success.

SetPin 15,INTL,RainFall
Sub RainFall
Rain=Rain+1
Print Rain
End Sub

But the interrupt does not trigger every time the Pin goes low.

Edit.. Just tried Pin 18 same problem

This is a new E-28 first time used, I will try another one.Edited by palcal 2018-12-20

"It is better to be ignorant and ask a stupid question than to be plain Stupid and not ask at all"

TassyJim

Guru

Joined: 07/08/2011
Location: Australia
Posts: 6283

Posted: 04:22am 19 Dec 2018

Copy link to clipboard

Print this post

Maybe it needs a pull-up resistor. My flow meters have one built-in.

VK7JH
MMedit

TassyJim

Guru

Joined: 07/08/2011
Location: Australia
Posts: 6283

Posted: 04:50am 19 Dec 2018

Copy link to clipboard

Print this post

My flow meters use a WSH130 hall effect and the ones that got fried with the lightning 3 years ago were replaced with A3144 hall effect.
They have a 10k resistor as a pull-up and I run mine at 5V. (The counting pins are 5V tolerant)

You might not be pulling the signal pin low enough if the pull-up is too low resistance.

Jim

VK7JH
MMedit

palcal

Guru

Joined: 12/10/2011
Location: Australia
Posts: 1993

Posted: 05:07am 19 Dec 2018

Copy link to clipboard

Print this post

Got it working with COUNT pin on a 28-Backpack, must be a problem with the E-28.
Thanks Jim.

Edit...now working with E-28Edited by palcal 2018-12-20

"It is better to be ignorant and ask a stupid question than to be plain Stupid and not ask at all"

Print this page

To reply to this topic, you need to log in.