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Figure from:DEVELOPMENT OF A REMOTE CONTROLLED VERTICALLY ADJUSTABLE WHITE BOARD

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Figure 17 Complete assembled remote controlled vertically adjusted motorized board.

Figure 17 Complete assembled remote controlled vertically adjusted motorized board.

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The motorize board often times needs rigid support so as to stand firm in a class room. This was why stands were made withwooden frames having dimensions of 65mm by 65mm and a length of 1735mm. These were prepared from wooden beams of 100mm by 100mm and a ength of 3300mm. This stands were grooved at the center 18mm wide to a depth of 40mm so as to support the white board. Also, support beam with a length of 1210mm and thickness of 65mm by 25mm was produced to give rigidity at the top. The base which wi | aid the whiteboard to stand was produced with the same dimension as the frames discussed above but with a length o 890mm. Support dash board was also produced from plywood of 16mm to give rigidity at the bottom. The dimension of the dashboar is 1244.41mm by 320mm. The CAD drawing showing this component is shown in Figure 1 and 2.
The motorize board often times needs rigid support so as to stand firm in a class room. This was why stands were made withwooden frames having dimensions of 65mm by 65mm and a length of 1735mm. These were prepared from wooden beams of 100mm by 100mm and a ength of 3300mm. This stands were grooved at the center 18mm wide to a depth of 40mm so as to support the white board. Also, support beam with a length of 1210mm and thickness of 65mm by 25mm was produced to give rigidity at the top. The base which wi | aid the whiteboard to stand was produced with the same dimension as the frames discussed above but with a length o 890mm. Support dash board was also produced from plywood of 16mm to give rigidity at the bottom. The dimension of the dashboar is 1244.41mm by 320mm. The CAD drawing showing this component is shown in Figure 1 and 2.
The rollersused asshown in Figure 4 were bought in the local market. This roller was fixed at the side of the solid Whiteboard a: shown in Figure 3. This was done to reduce fiction when the board slides through the grove on the frame. The motorized jack as shown in Figure 5 was adopted from the mechanism used to position a satellite dish receiver. The jack is made up of a 0.5hp motor, gears and a treaded shaft which ensures good toque. The power specification for the system to work is 36V DC. During the fabrication, 30V DC was used.
The rollersused asshown in Figure 4 were bought in the local market. This roller was fixed at the side of the solid Whiteboard a: shown in Figure 3. This was done to reduce fiction when the board slides through the grove on the frame. The motorized jack as shown in Figure 5 was adopted from the mechanism used to position a satellite dish receiver. The jack is made up of a 0.5hp motor, gears and a treaded shaft which ensures good toque. The power specification for the system to work is 36V DC. During the fabrication, 30V DC was used.
The jack grip was made from mild steel plate with thickness of 2mm. The plate was cut to a dimension of 50mm by 50mm so as to form a grip which will couple the Whiteboard with the jack. The plate was formed into U shape as shown in Figure 6 and drilled at the edges with a hole of diameter 12mm which accommodates the bolt which was used to couple the jack to the board. This component was made from a 2mm thick mild steel plate. The plate was cut 18mm wide and 1600mm long. The reason for the selection of the material is to impede the rollers which are metal in structure from eaten up the wood as a result of friction. This rail was then installed into the grove.
The jack grip was made from mild steel plate with thickness of 2mm. The plate was cut to a dimension of 50mm by 50mm so as to form a grip which will couple the Whiteboard with the jack. The plate was formed into U shape as shown in Figure 6 and drilled at the edges with a hole of diameter 12mm which accommodates the bolt which was used to couple the jack to the board. This component was made from a 2mm thick mild steel plate. The plate was cut 18mm wide and 1600mm long. The reason for the selection of the material is to impede the rollers which are metal in structure from eaten up the wood as a result of friction. This rail was then installed into the grove.
The remote control is subdivided into two parts. These are the transmitter and the receiver. The block diagram in Figure 7 and Figure 8 shows the interconnectivity of the components of the transmitter and receiver.
The remote control is subdivided into two parts. These are the transmitter and the receiver. The block diagram in Figure 7 and Figure 8 shows the interconnectivity of the components of the transmitter and receiver.
This unit was produced via the use of 555 timer. The timer was connected in astable mode as shown in the circuit diagram in figure 9 below. The essence of this is to generate a 38 kHz square wave which is used as carrier wave. The carrier wave is modulated with the control signal so as to achieve 7 meters range of control. The 0.1nf capacitor is used to stop false trigger. While the combination of R, R», and C, gives the output frequency. This frequency is governed by the formulae
This unit was produced via the use of 555 timer. The timer was connected in astable mode as shown in the circuit diagram in figure 9 below. The essence of this is to generate a 38 kHz square wave which is used as carrier wave. The carrier wave is modulated with the control signal so as to achieve 7 meters range of control. The 0.1nf capacitor is used to stop false trigger. While the combination of R, R», and C, gives the output frequency. This frequency is governed by the formulae
Figure 9 Circuit diagram of A stable multivibrator
Figure 9 Circuit diagram of A stable multivibrator
This was achieved via the use of two NPN transistors. The purpose of having NAND gate is to be able to modulate the carrier wave with the control signal. The circuit diagram is shown in Figure 10 below. R,and R; are used to properly bias the transistors and R3 i: used to limit the current passing through the infrared LED. The max 232 was used as a serial buffer. In the transmitter, it ensures that the control signal from the controller reaches the NA ND gate while in the receiver it ensures that the received signal gets to the controller. The circuit in Figure 11 describes its connection.
This was achieved via the use of two NPN transistors. The purpose of having NAND gate is to be able to modulate the carrier wave with the control signal. The circuit diagram is shown in Figure 10 below. R,and R; are used to properly bias the transistors and R3 i: used to limit the current passing through the infrared LED. The max 232 was used as a serial buffer. In the transmitter, it ensures that the control signal from the controller reaches the NA ND gate while in the receiver it ensures that the received signal gets to the controller. The circuit in Figure 11 describes its connection.
The micro controller used is 89C51. This was selected among other types because of its availability in the market and affordability. it was wired up with other components as shown in Figure 12. After wards, Kiel C was used to write the code after which it was burned into the controller via a universal programmer. The capacitor at pin 9 is to aid delay so that the system properly booths before acting on the program. Pin 40 is connected to V ., (+5V) while pin 20 is grounded. This helps to power the chip. Pin 31 has to be connected
The micro controller used is 89C51. This was selected among other types because of its availability in the market and affordability. it was wired up with other components as shown in Figure 12. After wards, Kiel C was used to write the code after which it was burned into the controller via a universal programmer. The capacitor at pin 9 is to aid delay so that the system properly booths before acting on the program. Pin 40 is connected to V ., (+5V) while pin 20 is grounded. This helps to power the chip. Pin 31 has to be connected
0 V cc SO thet the controller can act on the program from within its own program memory. The controller in the transmitter is esponsible for the outputting of control signal through the serial transmitter pin (Pin11) while it reads the signal received at th ‘eceiver through pin 10. Note that the controller was clocked with a 12MHz crystal.
0 V cc SO thet the controller can act on the program from within its own program memory. The controller in the transmitter is esponsible for the outputting of control signal through the serial transmitter pin (Pin11) while it reads the signal received at th ‘eceiver through pin 10. Note that the controller was clocked with a 12MHz crystal.
Figure 13 circuit diagram of the buttons. Three buttons were used. One was dedicated to control the up motion of the jack, another the down motion and the last was the halt action. These buttons were connected in series with a resistor to ensure a difference in logic when pressed. The points X, Y, Z are the points that output the logic. They output logic one when not pressed and logic zero when pressed. The circuit diagram is shown in Figure 13.
Figure 13 circuit diagram of the buttons. Three buttons were used. One was dedicated to control the up motion of the jack, another the down motion and the last was the halt action. These buttons were connected in series with a resistor to ensure a difference in logic when pressed. The points X, Y, Z are the points that output the logic. They output logic one when not pressed and logic zero when pressed. The circuit diagram is shown in Figure 13.
The relay is an electromagnetic switch. It help in the changing of the orientation of the jack in this project. To achieve this, two relays were used. These relays had to be controlled by the controller of the receiver. However it was not possible to do that directly since the current demand of the relay is more than what the controller can deliver. To overcome this ill, two A1015 transistors had to be used to drive the relays. This is shown in Figure 13.
The relay is an electromagnetic switch. It help in the changing of the orientation of the jack in this project. To achieve this, two relays were used. These relays had to be controlled by the controller of the receiver. However it was not possible to do that directly since the current demand of the relay is more than what the controller can deliver. To overcome this ill, two A1015 transistors had to be used to drive the relays. This is shown in Figure 13.
Figure 15 Complete circuit diagram of transmitter. The sub unit shown in Figure 15 consists of an astable multivibrator which generates the 38 kHz needed for modulation. When the button is pressed, the control signal is outputted from the controller to the max 232. This signal in modulated with the 38 kHz carrier signal. This will help to push the message out to the LED. The sub unit in figure 16 shows the IR receiver which captures the message and pass it to Max232. The signal is the passed to the controller which interprets it and acts on it. The assembled board is shown in Figure 17.
Figure 15 Complete circuit diagram of transmitter. The sub unit shown in Figure 15 consists of an astable multivibrator which generates the 38 kHz needed for modulation. When the button is pressed, the control signal is outputted from the controller to the max 232. This signal in modulated with the 38 kHz carrier signal. This will help to push the message out to the LED. The sub unit in figure 16 shows the IR receiver which captures the message and pass it to Max232. The signal is the passed to the controller which interprets it and acts on it. The assembled board is shown in Figure 17.
Table 1.Actions of sub units when tested. Furthermore, unlike the manual Whiteboard which needs human effort to adjust the height, the remote controlled whiteboard was operated via the use of a remote. Also the transmitter and receiver were tested to ensure communication. From the test it was observed that the system worked as anticipated. The remote control worked within the range of 7 meters. Furthermore, the comfort of teachers with heights between 4.6 feet to height of 6.7 feet was tested. It was observed to be comfortable Also, in a class of same level seat arrangement, the comfort of the students in viewing the board was achieved. After the completion of the work, unlike the manual Whiteboard that has nothing to measure with a multimeter since there are no circuit involved, essential parameters of some sections of the remote controlled motorize board was measured to ensure that the components were in good condition. This is illustrated with the Table 1 below.
Table 1.Actions of sub units when tested. Furthermore, unlike the manual Whiteboard which needs human effort to adjust the height, the remote controlled whiteboard was operated via the use of a remote. Also the transmitter and receiver were tested to ensure communication. From the test it was observed that the system worked as anticipated. The remote control worked within the range of 7 meters. Furthermore, the comfort of teachers with heights between 4.6 feet to height of 6.7 feet was tested. It was observed to be comfortable Also, in a class of same level seat arrangement, the comfort of the students in viewing the board was achieved. After the completion of the work, unlike the manual Whiteboard that has nothing to measure with a multimeter since there are no circuit involved, essential parameters of some sections of the remote controlled motorize board was measured to ensure that the components were in good condition. This is illustrated with the Table 1 below.