How do I calculate the rpm of the fan connected to my Raspberry Pi? [closed]
So what I've got is a Noctua fan(product link: https://noctua.at/en/products/fan/nf-a4x20-5v/specification) connected to a Raspberry Pi 3. I want to know the RPM of the fan at every second interval. I have a python script that gives me a value for the RPM but the RPM does not seem to be accurate. The fan speed is 5000rpm(+/-10%) at full capacity whereas the script gives an RPM value which is half of what is expected. I need help with how to get an accurate reading using PWM(pulse width modulation) or any other technique.
def calculate_elapse(channel): # callback function
global pulse, start_timer, elapse
pulse+=1 # increase pulse by 1 whenever interrupt occurred
elapse = time.time() - start_timer # elapse for every 1 complete rotation made!
start_timer = time.time() # let current time equals to start_timer
def calculate_speed(r_cm):
global pulse,elapse,rpm,dist_km,dist_meas,km_per_sec,km_per_hour
if elapse !=0: # to avoid DivisionByZero error
rpm = 1/elapse * 60
circ_cm = (2*math.pi)*r_cm # calculate wheel circumference in CM
dist_km = circ_cm/100000 # convert cm to km
km_per_sec = dist_km / elapse # calculate KM/sec
km_per_hour = km_per_sec * 3600 # calculate KM/h
dist_meas = (dist_km*pulse)*1000 # measure distance traverse in meter
return km_per_hour
Screen grab of the output that I am getting
python raspberry-pi fan raspbian sensors
asked Jan 22 at 0:53
jaitjait
62
closed as off-topic by DavidPostill♦ Jan 22 at 15:08
This question appears to be off-topic. The users who voted to close gave this specific reason:
- "This question is not about computer hardware or software, within the scope defined in the help center." – DavidPostill
If this question can be reworded to fit the rules in the help center, please edit the question.
add a comment |
So what I've got is a Noctua fan(product link: https://noctua.at/en/products/fan/nf-a4x20-5v/specification) connected to a Raspberry Pi 3. I want to know the RPM of the fan at every second interval. I have a python script that gives me a value for the RPM but the RPM does not seem to be accurate. The fan speed is 5000rpm(+/-10%) at full capacity whereas the script gives an RPM value which is half of what is expected. I need help with how to get an accurate reading using PWM(pulse width modulation) or any other technique.
def calculate_elapse(channel): # callback function
global pulse, start_timer, elapse
pulse+=1 # increase pulse by 1 whenever interrupt occurred
elapse = time.time() - start_timer # elapse for every 1 complete rotation made!
start_timer = time.time() # let current time equals to start_timer
def calculate_speed(r_cm):
global pulse,elapse,rpm,dist_km,dist_meas,km_per_sec,km_per_hour
if elapse !=0: # to avoid DivisionByZero error
rpm = 1/elapse * 60
circ_cm = (2*math.pi)*r_cm # calculate wheel circumference in CM
dist_km = circ_cm/100000 # convert cm to km
km_per_sec = dist_km / elapse # calculate KM/sec
km_per_hour = km_per_sec * 3600 # calculate KM/h
dist_meas = (dist_km*pulse)*1000 # measure distance traverse in meter
return km_per_hour
Screen grab of the output that I am getting
python raspberry-pi fan raspbian sensors
asked Jan 22 at 0:53
jaitjait
62
closed as off-topic by DavidPostill♦ Jan 22 at 15:08
This question appears to be off-topic. The users who voted to close gave this specific reason:
- "This question is not about computer hardware or software, within the scope defined in the help center." – DavidPostill
If this question can be reworded to fit the rules in the help center, please edit the question.
Welcome to Super User! Issues specific to programming and software development are off topic, see On-Topic. Try Stack Overflow but please first read How do I ask a good question?.
– DavidPostill♦
Jan 22 at 15:09
add a comment |
So what I've got is a Noctua fan(product link: https://noctua.at/en/products/fan/nf-a4x20-5v/specification) connected to a Raspberry Pi 3. I want to know the RPM of the fan at every second interval. I have a python script that gives me a value for the RPM but the RPM does not seem to be accurate. The fan speed is 5000rpm(+/-10%) at full capacity whereas the script gives an RPM value which is half of what is expected. I need help with how to get an accurate reading using PWM(pulse width modulation) or any other technique.
def calculate_elapse(channel): # callback function
global pulse, start_timer, elapse
pulse+=1 # increase pulse by 1 whenever interrupt occurred
elapse = time.time() - start_timer # elapse for every 1 complete rotation made!
start_timer = time.time() # let current time equals to start_timer
def calculate_speed(r_cm):
global pulse,elapse,rpm,dist_km,dist_meas,km_per_sec,km_per_hour
if elapse !=0: # to avoid DivisionByZero error
rpm = 1/elapse * 60
circ_cm = (2*math.pi)*r_cm # calculate wheel circumference in CM
dist_km = circ_cm/100000 # convert cm to km
km_per_sec = dist_km / elapse # calculate KM/sec
km_per_hour = km_per_sec * 3600 # calculate KM/h
dist_meas = (dist_km*pulse)*1000 # measure distance traverse in meter
return km_per_hour
Screen grab of the output that I am getting
python raspberry-pi fan raspbian sensors
asked Jan 22 at 0:53
jaitjait
62
So what I've got is a Noctua fan(product link: https://noctua.at/en/products/fan/nf-a4x20-5v/specification) connected to a Raspberry Pi 3. I want to know the RPM of the fan at every second interval. I have a python script that gives me a value for the RPM but the RPM does not seem to be accurate. The fan speed is 5000rpm(+/-10%) at full capacity whereas the script gives an RPM value which is half of what is expected. I need help with how to get an accurate reading using PWM(pulse width modulation) or any other technique.
def calculate_elapse(channel): # callback function
global pulse, start_timer, elapse
pulse+=1 # increase pulse by 1 whenever interrupt occurred
elapse = time.time() - start_timer # elapse for every 1 complete rotation made!
start_timer = time.time() # let current time equals to start_timer
def calculate_speed(r_cm):
global pulse,elapse,rpm,dist_km,dist_meas,km_per_sec,km_per_hour
if elapse !=0: # to avoid DivisionByZero error
rpm = 1/elapse * 60
circ_cm = (2*math.pi)*r_cm # calculate wheel circumference in CM
dist_km = circ_cm/100000 # convert cm to km
km_per_sec = dist_km / elapse # calculate KM/sec
km_per_hour = km_per_sec * 3600 # calculate KM/h
dist_meas = (dist_km*pulse)*1000 # measure distance traverse in meter
return km_per_hour
Screen grab of the output that I am getting
python raspberry-pi fan raspbian sensors
python raspberry-pi fan raspbian sensors
asked Jan 22 at 0:53
jaitjait
62
asked Jan 22 at 0:53
jaitjait
62
asked Jan 22 at 0:53
jaitjait
62
asked Jan 22 at 0:53
jaitjait
62
asked Jan 22 at 0:53
jaitjait
62
62
closed as off-topic by DavidPostill♦ Jan 22 at 15:08
This question appears to be off-topic. The users who voted to close gave this specific reason:
- "This question is not about computer hardware or software, within the scope defined in the help center." – DavidPostill
If this question can be reworded to fit the rules in the help center, please edit the question.
closed as off-topic by DavidPostill♦ Jan 22 at 15:08
This question appears to be off-topic. The users who voted to close gave this specific reason:
- "This question is not about computer hardware or software, within the scope defined in the help center." – DavidPostill
If this question can be reworded to fit the rules in the help center, please edit the question.
Welcome to Super User! Issues specific to programming and software development are off topic, see On-Topic. Try Stack Overflow but please first read How do I ask a good question?.
– DavidPostill♦
Jan 22 at 15:09
add a comment |
Welcome to Super User! Issues specific to programming and software development are off topic, see On-Topic. Try Stack Overflow but please first read How do I ask a good question?.
– DavidPostill♦
Jan 22 at 15:09
Welcome to Super User! Issues specific to programming and software development are off topic, see On-Topic. Try Stack Overflow but please first read How do I ask a good question?.
– DavidPostill♦
Jan 22 at 15:09
Welcome to Super User! Issues specific to programming and software development are off topic, see On-Topic. Try Stack Overflow but please first read How do I ask a good question?.
– DavidPostill♦
Jan 22 at 15:09
add a comment |
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Welcome to Super User! Issues specific to programming and software development are off topic, see On-Topic. Try Stack Overflow but please first read How do I ask a good question?.
– DavidPostill♦
Jan 22 at 15:09