What is the fastest reasonable polling frequency

I want to connect my doorbell directly to an imp. I’ll be repurposing another board that I have (based one the jane design) and the only free pin that is directly connected to the imp is #5. I also have an i/o expander with 2 pins available. I would rather use one of the pins on the i/o expander (will use #5 as ADC input).

Now, I want to poll the doorbell pin every 100ms or so - that way I will not miss an event. Is this reasonable?

Also, any reason callback support for pins other than #1 have not yet been implemented? A firmware update to enable this was mentioned in the api documentation.

50ms might be better so as not to miss short presses, but that should work.

Does the IO expander not have an interrupt (change detect) mode?

Not sure what you mean by callback support. The imp does pin changed callbacks on all pins?

I guess you call it wakeup. Essentially, how to detect an external event on a different pin.

Also, is the part of the IDE where you connect arrows to things down?

Is your board going to be battery powered? or do you have good old reliable power. You may not need to worry about a pin waking the device if you do not need to put it down for power savings. As Hugo said all of the pins will trigger an event or callback.

for configuring the pin


you use this: where function is the name of the function that you want to run when the pin state changes

pin.configure(DIGITAL_IN, function)

the “connect arrows to things” is deprecated and development is done with the Agents. It takes a bit to get used to the change but I think it is better because when we share examples everything about the connection can be explained in the code without having to explain how all the noddles are hooked up and what entries are in the settings boxes.