I am on working in a project where i need to calculate the time period of signal using interuptts and timers but as i am new to arduino so donot know alot about timers arduino offfers.if anybody can help me with how to start and stop the timer using interupts and the frequency i am getting is from 0hz to 100hz.sample code will be very much appreciated
Can you describe the signal a bit better please as this will determine what the code would need to do.
Is it a single signal wire that rises/falls and you want to measure the time between two rising edges or is it two separate signal wires and you want to measure the time between the rising edge on one wire and the rising edge on the other wire.
For both examples you probably don't really need to set, start & stop a timer as you can just mark time of the built in timer for the first and second edge and subtract the first from the latter to get the duration.
it is a signal wire from a sensor which gives output in form of pulses with freq range from 0 to 100hz and i want yo calculate time period between two rising .e i want to start timer when rising comes and stop timer when second rising edge come but accuracy is really important here.
if there is any other way to do it i will very much like to learn it.
thankx for giving my problem ur time.
minhas:
it is a signal wire from a sensor which gives output in form of pulses with freq range from 0 to 100hz and i want yo calculate time period between two rising .e i want to start timer when rising comes and stop timer when second rising edge come but accuracy is really important here.
if there is any other way to do it i will very much like to learn it.
thankx for giving my problem ur time.
Are the pulses continuous and you want a rolling frequency count between consecutive pulses or are they a single start and single stop pulse. How do you determine what pulse is the start pulse?
What is the voltage on the signal wire as Arduino UNO pins can only handle 0-5V input but also need something about 3.5V to register as a high on a pin.
When you say accuracy is important then what level of accuracy are you talking about. You might only get down to about 4uS accuracy (4 millionths of a second)
it is infact a doplar radar sensor and i want to calculate its frequency when it detect any motion.is there any efficeient way to find the frequency and i case of no motion detected the SENSOR give notning at output.if you can kindly help me on this.and output frequency is in range of 0=100hz for which i thick 6us will be enough.
Can you provide a data sheet for the sensor?
this is the link to datasheet of the sensor. https://www.limpkin.fr/public/HB100/HB100_Microwave_Sensor_Application_Note.pdf
There is code here on github
It uses the FreqMeasure library and the output signal from the module needs amplifcation.
i have comerough through freq mesure liberary but most of times they have said it works better for the freq range from 50hz to several kilo hz while i have a lot of reading from 0 to 50hz for human movements so i think the interupts method will work better but with interupts i can only be able to detect freq based on the moton detected on the bounderies of range of sensors which is quite diifferent than the its freq if the motion is detected nearer to the sensor.thank you for ur help and i hope i will find an answer to address my this problem here.
The freqMeasure library uses a timer interrupt. It is the most accurate way to time pulse edges. Did you try the github code? When I have looked at the FreqMeasure library I didn't see any limitation for the lower frequencies. In fact the git hub page for the library states
FreqMeasure: best for 0.1 Hz to 1 kHz