![]() ![]() The FreqPeriodCounter is automatically synchronized from the beginning. Hereafter, the counter is synchronized, and the counter is ready after each period. At the start, firstly two periods must be measured before the measurement is valid and the counter is ready. In most cases, you do not notice this, but for nitpickers, the FreqPeriodCounter is equipped with synchronization so that measurements are never invalid. It is a fact that a frequency counter can't do valid measurements starting from the first pulse. In order to make use of floating points, do the following:įloat hz = 1000/counter.period // period in ms Frequency counter synchronization Unsigned long centiHz = counter.hertz(100) Ĭounter.herz() is 16, counter.herz(100) is 1623. The precision has to be specified, for example 100: Therefore, the frequency is measured in integer with a multiplying factor. However, this will take a lot of memory because the floating point library will be used. To measure the frequency more accurate than 1Hz, we can use floating points, e.g. m(PWMpin, 300, 70) // duty cycle, period Frequency counter using interrupt #include Ĭonst byte counterPin = 3 // connect d3 to d9Ĭonst byte PWMpin = 9 // PWM only d9 or d10įreqPeriodCounter counter(counterPin, micros, 0) ![]() We use the Arduino itself to generate a frequency signal, just connect d3 to d9. You don't need a separate function generator to test the FreqPeriodCounter. Examples with the frequency generated by the Arduino The period time is measured in μs, the frequency is displayed in Hz. elapsedTime Use this to detect if there is no frequency signal: (elapsedTime > timeOut).ready() If an entire period is measured, ready is true.We can take a debounce time of about 10ms if the frequency comes from a mechanically switch: counter(counterPin, micros, 10).The measurement can be done in milli seconds or micro seconds. The constructor has a function as argument, here we pass the required function: millis or micros.The maximum frequency with polling is approximately 25kHz.The FreqPeriodCounter is equipped with synchronization so that also the first measurements are valid.The frequency counter can be used in two ways:.Important: the Frequency / period counter works without hardware timers.Īrduino frequency counter used in e-bike Watt meter Frequency counter used in pedelec legalisation deviceĪrduino frequency counter used in scale interfaceĭownload the library from GitHub, you will find here program examples too.Ĭounting multiple frequencies with polling and interrupts Simple example #include įreqPeriodCounter counter(counterPin, micros) The library is also compatible with Arduino boards that use the SAMD21: Arduino Zero, SAM 15x15, etc. Here is a frequency counter for the Arduino, it is used in many projects, such as the pedelec legalisation device and the scale interface. ![]()
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