![]() This way, between pin 9 an 10, the voltage alternate between both 0V, pin 9 +5V, both 0V, pin 10 +5V. To make it even more similar to a sine wave, we use the Phase-correct PWM. There is a trick that can be done: the two outputs of a timer can be run in opposite phase, by inverting one of the outputs. To run the coil most effectively, we’d like to use a true AC source. This is high enough that the Arduino does not go into overcurrent. We produce a signal with a frequency of 516kHz, resulting in an impedance of 2pi*f*L=275Ohm. ![]() So for N=20 and R=0.0425 gives L=85muH, which was confirmed with the component tester. The self-inductance of this type of coil with N windings and a radius R is ~5muH * N^2 * R. I used a paper roll of 8.5cm diameter and enameled wire of 0.13mm diameter to make 2 coils: the primary with 20 turns, the secondary with 50 turns. A coil with a high frequency signal can transfer power to another nearby coil through induction, without electrical contact.įirst prepare the coils. ![]() It is not uncommon to charge a smart watch without cables, but the same can easily be part of an Arduino project. A second independent DAC channel can be run with timer1 on pin 10. In the example, the DAC output is steered with a potentiometer. To avoid that, it can be buffered with an opamp, or another combination of R and C can be chosen, for example 1kOhm with 10muF. Note that this DAC has a very high output impedance (10kOhm), so the voltage will drop significantly if it draws current. The peak-to-peak ripple is at most 5V*0.5*T/(RC)=16mV, which is considered sufficient here. If we use a 1muF capacitor and a 10kOhm resistor, RC=10ms. The period we get for a 10-bit precision is 1024/16MHz= 64mus. The time-scale of the RC circuit should be much larger than the period of the PWM signal to reduce the ripple. The RC circuit is a first-order low-pass filter and it will have some ripple. The resolution of the 8-bit timers would be 5V/256=20mV, so we opt for Timer1 to get 10-bit resolution. The characteristics are determined by the PWM frequency and the values of the resistor and capacitor. A capacitor is connected through a resistor to a PWM pin. With just one capacitor and resistor, timer1 can be used to create an analog voltage with a resolution of 5mV or better.Ī low-pass filter can ‘average’ the PWM signal to an analog voltage. Some modules take an analog voltage to regulate a parameter (display contrast, detection threshold etc). Serial.The Arduino does not have a true analog output. Have changed the code now I get as you say 503 / 504 value #include Do that and then your cnt variable will increment only once per cycle of your waveform generator. TCNT1H = 0x0B //reload counter high value #pragma interrupt_handler timer1_ovf_isr:iv_TIM1_OVF Will try with this wizzard (ICC AVR) to correctly setup a interrupt (what do you think)? When you initialize the registers you have Normal Mode (WGM13:WGM10 =0) which only counts up to OxFFFF and resets. The factor of 2 is only relevant when you are using the timer in a mode where it counts up and down. I think you have set up the overflow for. if flag is true then the frequency is displayed on serial monitor ISR(TIMER1_OVF_vect) // interrupt service routineĬnt1 = cnt // copy value to some other variable TIMSK1 |= (1 << TOIE1) // enable timer overflow interrupt NoInterrupts() // disable all interruptsĪttachInterrupt(digitalPinToInterrupt(interruptPinTemp), beriTemperatura, CHANGE) Serial.begin(9600) // inicializacija serijskega porta I don't know what I'am doing wrong but instead od 1000 counts I get 1006 or 1007 counts the code is here (just for sample) each second I would like to read a counter value which is incremented when a signal is present on pin 2 (attach interrupt).
0 Comments
Leave a Reply. |
Details
AuthorWrite something about yourself. No need to be fancy, just an overview. ArchivesCategories |