Autonomous Beacon Seeking Blimp Kenton Weigold Marcin Ochman Brian Schmalzer
Outline Introduction Design Overview Beacon Blimp Hardware Software Difficulties and Risks Testing Strategy Weight Constraints Cost analysis
Introduction Helium-supported, self-propelled autonomous blimp Maintains an altitude of 1.5 meters Seeks out beacon that broadcasts an infrared signal at 38KHz Able to detect beacon at least 7 meters Lands within 40cm of target beacon
Beacon LEDs TSAL degree beam TSAL degree beam 555-timer (LM555CM) Create 38KHz pulse 6V Li-Ion Batteries (2CR5) with 5V Voltage Regulator (KA7805) Drivers (SN74LS244EW) Supply up to 8 IR LEDs each with sufficient current Hemispherical configuration
Sensor Placement
Sensor Operation Two IR detectors for direction One IR detector for determining if beacon is found One ultrasonic range finder for altitude determination
Infrared Sensors Panasonic PNA4611M 5V Operating Voltage Detects pulses of 38KHz at a wavelength of 940nm Maximum typical reception distance of 16 meters Typical current consumption of 2.4 mA Active-Low TTL output (0-5V) <1 gram in weight
Ultrasonic Range Finder MaxSonar-EZ-1 5V Operating Voltage 16cm – 6.45 meter range <16cm ranges as 16cm 2.5cm resolution Typical current consumption of 2 mA 49ms sample interval Outputs Serial Analog (10mV/2.54cm) PWM (147uS/2.54cm) 4.3 grams in weight
Blimp Mobility Altitude Control Vertical-axis motor Propulsion/Direction Control Two motors on the horizontal plane capable of independent rotation in both directions
Propulsion Assembly Motors 1.5V Operating Voltage 22mA consumption 6400rpm 4.0gcm torque U80 High thrust propellers Total weight of 36 grams
Power Supply 6V Lithium-Ion Rechargeable Battery (2CR5) 48.5 grams in weight 600 mAh 5V Voltage Regulator (KA7805) Input: 5V-35V Output: 5V up to 1A 1.8V Voltage Regulator Input: 3V-26V Output: 1.8V up to 0.5A
Microcontroller Freescale MC9S12DT bit device 256KB Flash 4KB EEPROM 12 KB RAM 2 10-bit, 8-ch ATD 16 discrete I/O (Port A, Port B) And more…
User Interface and Emergency Tether A single power switch will start blimp search pattern To ensure safe operation, the blimp will always remain tethered A strong tug will release the power cut- off pin
Blimp System Diagram
Algorithm
Difficulties and Risks IR Pollution/Reflections Infrared Guards Digital Filter/Software Filter Weight Limitations Strip non-essential components Maintaining Neutral Buoyancy Maintain helium pressure Ballast
Difficulties and Risks (cont) Air Currents Avoid areas with noticeable air currents Inverted Airfoil Effect Mount Fins Use short thrust bursts Insufficient Power Reduce power consumption Increase battery power
Testing Strategy Module Tests/Interface Tests IR Ultrasonic components Propulsion Power Integration Tests Blimp Beacon Bench Tests Field Tests
Weight Constraints PartQtyIndividual Weight (g) Total Weight (g) IR Sensors3< Ultrasonic Range Finder14.3 H-bridges3< Blimp Propeller Assembly/Motors/Propellers Freescale CSM12D138.0 Indicator LEDs3< Li-Ion Battery V Voltage Regulator V Voltage Regulator11.0 Envelope163 Weight available for Additional Logic Components/Interconnections, mounts, and landing gear. N/A ~55.2 Total 250
Cost Analysis PartSupplierQtyIndividual CostTotal Cost IR Sensor (PNA4612M) Ultrasonic Range Finder (MaxSonar-EZ-1) IR LED (TSAL6100)Reynolds Electronics30$0.70$21.00 IR LED (TSAL7200)Reynolds Electronics30$0.65$32.50 H-bridges (ZHB6518CT) RC Toy Blimp (includes motor mounts an motors) Propellers (U80)FXAeromodels3$1.75$5.25 Freescale CSM12DFreescale1$120.00$0.00 6V Li-Ion Batteries and Charger (KIT2CR5) Thomas Distributing1$29.97 Additional 6V Li-Ion Battery (2CR5) Thomas Distributing2$14.97$ V Regulator (TL760M18)Radio Shack21.65$ V Regulator (KA7805Radio Shack11.65$1.65 Indicator LEDsTeam3$0.14$0.00 Additional Logic Components/Interconnects TeamN/A$N/A$0.00 Drivers (SN74LS244EW)Mouser Electronics6$0.77$4.62 Clock (LM555CM)Mouser Electronics1$0.27 HeliumParty CityN/A~$0.30/cu.ft.$3.00 Total CostN/A $231.36
Questions/Comments