Here comes the Bus! (8) Measurement and control

摘要

In the previous instalment in this series we looked at a simple protocol for communicating the results of measurements. Now we look at how the protocol can be used in a control application. To this end we will add a couple of simple components to the experimental board: a light-dependent resistor and a relay. Many readers will probably already have suitable devices in their junk box. However, the flexibility of the sensor node should not be underestimated: it can output values in a variety of different units and autonomously check readings against pre-set thresholds.