The following three questions are detailed design exercises that ask you to consider the integration of sensors, logic and actuators in real-world electronic devices. Together, they assess your understanding of the materials in Blocks 1-5. A separate word count is suggested for each question in this part. Read through the whole of Part Il before beginning your answer. It is proposed to build a 'socially intelligent self-organising robotic garden' as part of an art installation One of the main ideas is that the plants have intelligent personalities and can move, with each supported on a small wheeled robotic platform. This enables the plants to interact and move in ways that form emergent patterns in the garden (Figure 7(a)). The visitors to the installation are also part of this system and can interact through their mobile phones over the internet (Figure 7(b)). The objective of the installation is for the plants and visitors to interact as a social intelligence to guide the self-organisation of the garden into emergent patterns. These are to be curated over time to create an evolving history This project involves some groundbreaking ideas in self-organising communities and the emergence of stable and unstable social forms. It involves a lot of technologies and many subsystems Figure 7 The robotic garden project: (a) an emergent pattern in the garden; (b) users interact with the system through their mobile phones Suppose you are a member of the design and engineering team responsible for this ambitious project. As a first step you are responsible for a feasibility study on the design and implementation of the mobile robotic platforms supporting the autonomous plants For the feasibility test it has been decided that the robot platforms have a diameter of 240 mm and must move on a grid of 250 x 250 mm squares as shown in Figure 8 and come to rest at any of the grid points where the grid lines intersect. The grid lines are black and the background is white. The test grid in Figure 8(b) is 14 x 14 squares, which is 12.25 m For this feasibility test you can assume there is just one robot platform on the grid trinket B C D Stop F G A E H I J K L M N O Figure 8 The robotic plant platforms must be able to move on a 250 mm x 250 mm grid: (a) moving the red robot to the blue target: (b) a computer simulation to move from D6 to K3 You can assume that the robot platforms have two driven wheels and two omni wheels (Figure 9 below and Figure 10 in Question 12), enabling them to move forward and backward and to turn 60 mm light sensor DO 200 mm 3 platform AL dh 0 omni wheel omni wheel light sensor drive wheel platform light sensor omni wheel drive wheel omni wheel Figure 9 The robots can move forward, backward and rotate, using two drive wheels and two omni wheels As shown in Figure 9, the sensor subsystem has four light sensors. Each sensor uses a photodiode to detect black lines or the white background. An LED is used to illuminate the line and background Your task is to design the circuitry for one of these sensors. This involves designing a photodiode subcircuit and an amplification subcircuit. You can assume that the range of photodiode currents is -11 A when a photodiode is over the black line and -40 PA when it is over the white background. The output of the sensor subsystem should be a positive voltage of 3.3 V for maximum brightness and should not exceed 1 V for minimum brightness These voltages will be used as input to the microprocessor in the logic subsystem. You are not required to design the logic subsystem. Assume that the LEDs operate at about 25 mA and each has a voltage drop of 1.3 V. If you use Multisim to design your circuit you can change the emission coefficient, N, from its default value of 1 to 1.75 to make the voltage drop approximately 1.3 volts. a. Photodiode subcircuit. Give a drawing of a photodiode circuit, explaining your choice of supply voltage. Include the photodiode specified above and an appropriate resistor. Show how you calculated the resistor value. Do not include the LED at this stage. Let the output of this circuit be the voltage between the photodiode and the resistor. Let this be called Vsensor The output of the photodiode subcircuit, Vsensor, should be about 120 mV when the photodiode is over the white background with maximum brightness Complete the following table. Table 2 Photodiode subcircuit voltages Power supply voltage for the photodiode Resistor value for Vsensor = 120 mV Output voltage over black (Vsensor) Output voltage over white (Vsensor) If you use Multisim Live to answer this question, remember that you must include a ground component for the SPICE simulation to work correctly. The following three questions are detailed design exercises that ask you to consider the integration of sensors, logic and actuators in real-world electronic devices. Together, they assess your understanding of the materials in Blocks 1-5. A separate word count is suggested for each question in this part. Read through the whole of Part Il before beginning your answer. It is proposed to build a 'socially intelligent self-organising robotic garden' as part of an art installation One of the main ideas is that the plants have intelligent personalities and can move, with each supported on a small wheeled robotic platform. This enables the plants to interact and move in ways that form emergent patterns in the garden (Figure 7(a)). The visitors to the installation are also part of this system and can interact through their mobile phones over the internet (Figure 7(b)). The objective of the installation is for the plants and visitors to interact as a social intelligence to guide the self-organisation of the garden into emergent patterns. These are to be curated over time to create an evolving history This project involves some groundbreaking ideas in self-organising communities and the emergence of stable and unstable social forms. It involves a lot of technologies and many subsystems Figure 7 The robotic garden project: (a) an emergent pattern in the garden; (b) users interact with the system through their mobile phones Suppose you are a member of the design and engineering team responsible for this ambitious project. As a first step you are responsible for a feasibility study on the design and implementation of the mobile robotic platforms supporting the autonomous plants For the feasibility test it has been decided that the robot platforms have a diameter of 240 mm and must move on a grid of 250 x 250 mm squares as shown in Figure 8 and come to rest at any of the grid points where the grid lines intersect. The grid lines are black and the background is white. The test grid in Figure 8(b) is 14 x 14 squares, which is 12.25 m For this feasibility test you can assume there is just one robot platform on the grid trinket B C D Stop F G A E H I J K L M N O Figure 8 The robotic plant platforms must be able to move on a 250 mm x 250 mm grid: (a) moving the red robot to the blue target: (b) a computer simulation to move from D6 to K3 You can assume that the robot platforms have two driven wheels and two omni wheels (Figure 9 below and Figure 10 in Question 12), enabling them to move forward and backward and to turn 60 mm light sensor DO 200 mm 3 platform AL dh 0 omni wheel omni wheel light sensor drive wheel platform light sensor omni wheel drive wheel omni wheel Figure 9 The robots can move forward, backward and rotate, using two drive wheels and two omni wheels As shown in Figure 9, the sensor subsystem has four light sensors. Each sensor uses a photodiode to detect black lines or the white background. An LED is used to illuminate the line and background Your task is to design the circuitry for one of these sensors. This involves designing a photodiode subcircuit and an amplification subcircuit. You can assume that the range of photodiode currents is -11 A when a photodiode is over the black line and -40 PA when it is over the white background. The output of the sensor subsystem should be a positive voltage of 3.3 V for maximum brightness and should not exceed 1 V for minimum brightness These voltages will be used as input to the microprocessor in the logic subsystem. You are not required to design the logic subsystem. Assume that the LEDs operate at about 25 mA and each has a voltage drop of 1.3 V. If you use Multisim to design your circuit you can change the emission coefficient, N, from its default value of 1 to 1.75 to make the voltage drop approximately 1.3 volts. a. Photodiode subcircuit. Give a drawing of a photodiode circuit, explaining your choice of supply voltage. Include the photodiode specified above and an appropriate resistor. Show how you calculated the resistor value. Do not include the LED at this stage. Let the output of this circuit be the voltage between the photodiode and the resistor. Let this be called Vsensor The output of the photodiode subcircuit, Vsensor, should be about 120 mV when the photodiode is over the white background with maximum brightness Complete the following table. Table 2 Photodiode subcircuit voltages Power supply voltage for the photodiode Resistor value for Vsensor = 120 mV Output voltage over black (Vsensor) Output voltage over white (Vsensor) If you use Multisim Live to answer this question, remember that you must include a ground component for the SPICE simulation to work correctly