I am working on a project where I have a spool spinning and I need to collect the weight per revolution. I was wondering if I could program the arduino for every time the hall effect sends a pulse I could collect a 4-20 ma signal from a weight indicator. I am looking to collect and chart this data if possible. I am new to the arduino world so please bear with me on any questions that might seem elementary.
Is this a student project?
stephens:
I am working on a project where I have a spool spinning and I need to collect the weight per revolution. I was wondering if I could program the arduino for every time the hall effect sends a pulse I could collect a 4-20 ma signal from a weight indicator. I am looking to collect and chart this data if possible. I am new to the arduino world so please bear with me on any questions that might seem elementary.
Sounds basically OK to me, but if you're going to chart the data, (on the PC I guess), it will take time to send it serially so you'll have to make sure there's time for everything during each revolution with a bit of calculating. What's the maximum speed of the spool?
It is a work project.
I am not exactly sure but probably around 200-300 rpm.
stephens:
It is a work project.I am not exactly sure but probably around 200-300 rpm.
Should be no problem at those speeds. At 300rpm, 5 revs per second, you'll have 200mS each revolution to process and send the data before receiving the next value - tons of time. 
Draw a picture showing the mechanical arrangement including the location of the load cell.
Is the the thing going onto the spool under tension? If so, in what direction is the force in relation to the load cell orientation?
This doesn't sound too difficult.
simple way to get this working would be as follows (in my opinion):
- write arduino sketch to collect weight measurement in a simple loop for ONLY the weight sensor.
- once that is working, write a separate arduino sketch to blink LED every revolution of whatever is turning.
- replace blink sketch portion with weight measurement fetch, and output to serial or LCD screen.
is this all you want to do?
attach a small magnet to the turning apparatus, and then use a reed switch to ground out arduino pin to trigger weight fetching and display.
tune out any lag trying various methods of organizing/optimizing calcs and code. sounds pretty simple.
Careless:
attach a small magnet to the turning apparatus, and then use a reed switch to ground out arduino pin to trigger weight fetching and display.
tune out any lag trying various methods of organizing/optimizing calcs and code. sounds pretty simple.
Why do you suggest a reed switch when stephens already said he intends to use a Hall-effect sensor? A Hall-effect sensor is a superior method, in my opinion. Is there some reason that I can't think of why he should change to a reed switch?
Thanks for all of the suggestions. This project is something that I have been task with at work and was wondering on the programming how I could get the weight indication based on the hall effect signal. Careless really helped on how to configure the programming to work based on the hall effect signal. I would have to agree with oldsteve the hall effect is Superior to a Reed switch.