Hi all, During the last couple of weeks I have worked on implementing most of the sysex-based messages. This was great fun, because it greatly facilitates interaction between Pharo on any platform and the real world with a variety of devices. Now I am at the point where I have to address the fundamentally asynchronous nature of the Firmata protocol. At present we store the answers from requests in instance variables, but we don't know when these are available. Sometimes the protocol allows for continuous updates, so reading the data is semi-realtime. This happens with analog inputs, but can also be used with i2c devices or encoders. Driving a stepper motor really needs a callback or notification mechanism. When you instruct the stepper to do a number of steps you must be notified when it is ready for the next move. At this point I want your input on what is the "Pharoic" way of doing this. I can think of announcements or using Taskit, or simply passing a block to be executed when the answer becomes available. Maybe someone can point me to examples in existing packages. By the way, in WiringPi this callback facility also is missing (wiringPiISRPin: pinNumber edgeType: edgeType function: aFunctionPointerOrCallback >> shouldBeImplemented). regards rob van lopik