RacingtoMars
Member
Dear all,
I have a cheap plastic 3-cup anemometer from Maplin that I'd like to 'calibrate' somewhat, as I reckon it won't have a linear response. Now, Sparkfun sell kit that looks identical to Maplin's only they're a bit more generous with information these days! Their kit here states that a full revolution equates to a wind-speed of nearly 1.5 mph.
Inside the one I have it's simply a magnetic reed switch and a basic magnet.
So, for most of the time I'm only going to be getting an 'imperial handful' of pulses per second. If it gets up to 50 then it's a storm! We plan to compare wind speeds with a digital hand-held anemometer to get calibration-ish data. The goal is to stick a couple in the garden to measure the wind speeds over several weeks / months, before building a tiny wind-turbine!
My main query is wondering whether to count pulses per second, or the period between pulses, with suitable de-bounce code for the reed switch.
(Or the third option; use optical or hall-effect electronics. In reality though, I'm not looking for scientific measurements and I could buy something already calibrated for around £50 that's more robust. I think this thing will disintegrate if I try to change its innards!!)
I've read through many posts about rpm counters, pulse counters, speedometers etc. but I'm still undecided on measuring duration between pulses or pulses per duration. I'd just like some guidance and thoughts please, especially if there's something else I've not considered..?
Thanks as always,
Craig & Family (and next door neighbour whom also fancies building a wind-turbine!)
I have a cheap plastic 3-cup anemometer from Maplin that I'd like to 'calibrate' somewhat, as I reckon it won't have a linear response. Now, Sparkfun sell kit that looks identical to Maplin's only they're a bit more generous with information these days! Their kit here states that a full revolution equates to a wind-speed of nearly 1.5 mph.
Inside the one I have it's simply a magnetic reed switch and a basic magnet.
So, for most of the time I'm only going to be getting an 'imperial handful' of pulses per second. If it gets up to 50 then it's a storm! We plan to compare wind speeds with a digital hand-held anemometer to get calibration-ish data. The goal is to stick a couple in the garden to measure the wind speeds over several weeks / months, before building a tiny wind-turbine!
My main query is wondering whether to count pulses per second, or the period between pulses, with suitable de-bounce code for the reed switch.
(Or the third option; use optical or hall-effect electronics. In reality though, I'm not looking for scientific measurements and I could buy something already calibrated for around £50 that's more robust. I think this thing will disintegrate if I try to change its innards!!)
I've read through many posts about rpm counters, pulse counters, speedometers etc. but I'm still undecided on measuring duration between pulses or pulses per duration. I'd just like some guidance and thoughts please, especially if there's something else I've not considered..?
Thanks as always,
Craig & Family (and next door neighbour whom also fancies building a wind-turbine!)