also low power wireless signals. Low Energy Consumption Because it uses low power signals, Bluetooth requires little energy and will use less battery or electrical power. Personal Area Network (PAN) Allows for multiple devices to be connected within its range. Table 3.2.1.1 Advantages of Bluetooth Technology Due to the many devices that have this technology and the success that it has, Bluetooth technologies do not have many disadvantages. Unfortunately, these disadvantages could be critical in meeting the desired goals for the project. Table 3.2.1.2 is the short list of disadvantages of Bluetooth technology. Disadvantages Explanation Range Most of the Bluetooth connections have a range up to 30 feet. Data Rate Bluetooth only offers 1 MBps. Security Greater range and radio frequency (RF) make it much
4 (blk) VOLTAGE +3.3V 5 (blk) GND GND 6 (blk) GND GND Table 3.2.2.9 – Pixhawk POWER (Used with permission from Pixhawk) Pin Signal Volt 1 (red) VCC +3.3V 2 (blk) !IO_LED_SAFETY GND 3 (blk) SAFETY GND Table 3.2.2.10 – Pixhawk SWITCH (Used with permission from Pixhawk) To program the Pixhawk flight controller, the APM:Copter firmware and Mission Planner software from ArduPilot will be used. The options from ArduPilot were chosen as is an abundance of information available and the software is open source. As the software is, it supports different command modes and contains different features, with the most noteworthy being: Return to Launchpoint – Utilizes the GPS module on board to return the quadcopter to its original launch location. Land – Automatic landing sequence. Follow Me – Follows the user around by utilizing the telemetry unit mounted to the quadcopter, and computer or tablet equipped with GPS. The computer receives its GPS coordinates and transmits them to the drone. Failsafe – Allows for a failsafe to be implemented in the event of a lost control signal or low battery conditions. Camera control with live video link capability. Data logging to an onboard SD card for debugging. The different flight are similar to what we want to accomplish with our quadcopter’s missions, but we want to execute it in a different manner. Since the source code will contain these different modes of flight, we will be able to modify
D4 in the schematics of the transistor below are used to turn on M1 and M2 with protecting them from overvoltage at the same time. The efficiency of the transmitter relies of the spacing between it and the receiver. Larger distance between the results in a lower power transfer efficiency. These are shown if tables 6.2.2d, 6.2.2e and 6.2.2f. The preferred choice for the design is the option with a 10.5mm gab shown in figure 6.2.2f. Figure 6.2.2a schematic of Transmitter LTC4125 (Used with Permission from Linear Technology) The pin configuration for the LTC 4120 receiver are shown in figure 6.2.2b Figure 6.2.2b Pin Configuration for the LTC 4125 Transmitter (Used with Permission from Linear Technology) Figure 6.2.2c schematic of Basic Transmitter by Powerbyproxi (Used with Permission from Linear Technology) SPECIFICATION WITH RECEIVER (NO LOAD) WITH RECEIVER (1.535W LOAD) Operational Frequency 129.5kHz 129.5kHz Input Voltage 4.99V 4.96V Input Current 0.154A 0.602A RMS Value of Tx Output AC Voltage 10.9V 10.5V Peak Value of Tx Output AC Voltage 15.2V 15.2V Receiver Output DC Voltage 23.9V 17.5V Standby Loss 0.768W N/A Efficiency N/A 51.4% 6.2.2d Transmitter circuit parameters 7.55mm Gap SPECIFICATION WITHOUT RECEIVER (STANDBY) WITH RECEIVER (NO LOAD) WITH RECEIVER (1.58W LOAD) Operational Frequency 130.5kHz 128.7kHz 128.9kHz Input Voltage 4.99V 4.99V 4.95V Input Current 0.15A 0.173A 0.676A