PICAXE Manual Section 1 - TechnoPujades - Free

www.picaxe.co.ukSection 1 11GETTING STARTEDMicrocontrollers, input and outputsA popular children’s electronic toy is shown in thediagram. This is a good example of a mechatronicsystem, as it uses an electronic circuit to control anumber of mechanisms. It also contains a number ofsensors so that it can react to changes when it ismoved (for example being put in a dark place orbeing turned upside down).Input transducers are electronic devices that detectchanges in the ‘real world’ and send signals into theprocess block of the electronic system.Some of the input transducers for the electronic toy are:• push switches on the front and back to detect when the toy is being ‘stroked’,and a switch in the mouth to detect when the toy is being ‘fed’• a light-dependent resistor (LDR) between the eyes to detect if it is light ordark• a microphone to detect noises and speech• a tilt switch to detect when the toy is being turned upside down• an infrared detector to detect infrared signals from other toysOutput transducers are electronic devices that can be switched on and off by theprocess block of the electronic system. Some of the output transducers of theelectronic toy are:• a motor to make the eyes and mouth move• a speaker to produce sounds• an infrared LED (light-emitting diode) to send signals to other toys.INPUT PROCESS OUTPUTmicrophoneinfra-redreceivermotorlightdependentresistormicrocontrollerinfra-redtransmittertilt switchspeakerpress switchThe microcontroller uses information from the input transducers to makedecisions about how to control the output devices. These decisions are made bythe control program, which is downloaded into the microcontroller. To changethe ‘behaviour’ of the toy it is simply a process of changing and downloading anew program into the microcontrollerrevolution(c) Revolution Education Ltd. Email: info@rev-ed.co.uk Web: www.rev-ed.co.ukVersion 6.9 07/2009All rights reserved.11