More real-time processing questions and answers
Questions
Q1. Describe five sensors and two actuators.
Q2. What is the purpose of an interface?
Q3. How does an analogue signal differ from a digital signal?
Q4. Why is the sample rate important?
Q5. Use the Internet for research. What is a solenoid valve? Describe two applications for a solenoid valve.
Answers
Q1. Sensors include thermistors, breathalysers, radar guns, Geiger counters, torque sensors, speedometers, oxygen sensors and any other sensible example. Actuators include stepper motors, computer controlled valves, hydraulic and pneumatic pistons and any other sensible examples.
Q2. Interfaces provide a means of connecting sensors to a computer system by providing the sockets / ports needed. Interfaces can change readings between analogue and digital. Interfaces can provide a means of switching between different ranges of voltages e.g. converting 0 – 1 V range to a 0 – 12 V range.
Q3. Digital values have only two values, on or off. Analogue values vary infinitely between two values.
Q4. When you take readings in a data logging system, you need to take enough readings so that you can analyse the results or plot the results on a graph. You need to look at the period of time that needs to be analysed and then decide how many readings need to be taken per unit of time, the sample rate. For example, a chemical reaction that lasts just 10 seconds may need to have data logged every tenth of a second whereas if you want to analyse the temperature on top of a mountain over a six month period, you may only need to take a reading once an hour.
Q5. A solenoid valve is an output device. A valve is opened and closed by the application or removal of an electric current, which runs through a coil. When a current is run through the coil, a magnetic field is created and this opens or closes the valve (depending upon how a particular solenoid valve is designed). Solenoid valves can be used to control the flow of gas and liquids.