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Practical Arduino Cool Projects for Open Source Hardware- P5

Practical Arduino Cool Projects for Open Source Hardware- P5: A schematic or circuit diagram is a diagram that describes the interconnections in an electrical or electronic device. In the projects presented in Practical Arduino, we’ve taken the approach of providing both a photograph and/or line drawing of the completed device along with a schematic. While learning to read schematics takes a modest investment of your time, it will prove useful time and time again as you develop your projects. With that in mind, we present a quick how-to in this section | CHAPTER 2 APPLIANCE REMOTE CONTROL Instructions Test and Investigate Appliance Remote Plug the appliance remote control receiver into a handy power outlet and then plug an appliance a small lamp is ideal when testing into the socket on the receiver. Test that the unit works correctly in factory form by using the remote control to turn the appliance on and off. There s no point doing a lot of work modifying something if it doesn t work as intended in the first place Also pay attention to how long you need to hold the button down for the transmitter to operate correctly. Some systems require you to hold the button for half a second or so and others will operate if you stab at it very briefly. You may find you need to adjust the button press time variable in the example programs that follow if your remote control has unusual characteristics. Some remotes also perform different functions depending on whether you hold the button down or not such as toggling a lamp on a brief press or fading it up down on a long press. The photo in Figure 2-3 shows two different appliance remote control sets. The set on the left is designed for Australian power sockets running at 240V and has four sets of on off buttons and can switch between four different ranges to control a total of 16 devices from one remote control. The receiver unit has a visual indication of status and is designed to be plugged into a wall socket then an appliance plugged into it. It also supports a ground connection so it s suitable for many types of appliances. Figure2-3. Appliance remote controls The set on the right is designed for U.S. power sockets running at 110V and has a much smaller transmitter but it can only turn one appliance on or off. This particular model doesn t have a ground 19 CHAPTER 2 APPLIANCE REMOTE CONTROL connection so it s suitable only for double-insulated appliances that don t require a ground pin such as most lamps. There are many other types of appliance remote controls available and