I got a scope and am troubleshooting an AC phase control circuit described in this article: ACPhaseControl.
It shows that the H11AA1 will output a zero crossing signal on every zero crossing. However, the data sheet (attached) indicates that it will only output a signal every one cycle. Please let me konw if you read the same.
Also, I attached a couple scope shots of pin 5 output and one that shows the measurements. The pin should be 5V normally, and when H11AA1 sends a signal, it connects the arduino input to ground. I am using the INPUT_PULLUP feature on pin 2. The signal looks good, though is every 16ms, hence my question above.
Second question is if the shot showing the noise is typical of what you see on an arduino?
Also, the measurement shows in the attached shots about 105mV difference between the 5V level and the H11AA1 signal level at zero crossing. i believe this is 5V minus 105mV. Or I am using the scope wrong. This might be an issue with the scope set up. another try shows the voltage droping to about 3.1V. Is that enough for a logic 0?
h11aa1_dataSheet.pdf (145 KB)