Difference between revisions of "F12: Evil Watchdog"
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==Testing and Technical Challenges== | ==Testing and Technical Challenges== | ||
| + | === Battery Life === | ||
| + | By far, the battery pack is the most vulnerable component in keeping the Evil Watchdog alive. Only five 1.5-volt AA batteries power the entire system. Possible solutions to this problem are to either use batteries with longer lifespans or to use rechargeable batteries to avoid wasting single-use cells. During testing, a variable-voltage DC power supply, grabbing power from a wall outlet, was used to power the project. This saved battery power later needed for demoing. | ||
| + | |||
| + | === Vehicle Weight === | ||
| + | The original toy car was designed to carry a lightweight circuit board that received RF signals to control the motors. When the car is torn apart and new components are added for this project, the amount of weight placed on the wheels rapidly increases. Additional weight requires extra torque from the wheels to move the carried load, which can drain the batteries much more quickly. The best way to alleviate this problem is to eliminate excess weight and to select the lightest available parts to be placed on the vehicle. | ||
==Conclusion== | ==Conclusion== | ||
Revision as of 09:04, 1 December 2012
Contents
Abstract
The Evil Watchdog takes the responsibilities of a pet guarding a house. It will roam around a predefined environment, avoid obstacles, and sound an alarm whenever foreign motion is detected.
Introduction
The objective of this project is to design a vehicle to imitate a guard dog. The following items will be incorporated to accomplish this goal :
- Motor driven chassis
- Vehicle will move in a random path detecting motion
- Vehicle will sound an alarm when motion is detected
Technology used
- Motion sensor
- Distance sensor
Team Members and Roles & Responsibilities
- Waymond Chen: Front motor control and distance sensor programming
- Hung Vuong: Distance and motion sensor programming
- Erik Montoya: Backside motor control and programming
Schedule
| Starting | Ending | Planned Activities | Actual |
|---|---|---|---|
| Oct 26, 2012 | Nov 1, 2012 |
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| Nov 2, 2012 | Nov 8, 2012 |
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| Nov 9, 2012 | Nov 15, 2012 |
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| Nov 16, 2012 | Nov 22, 2012 |
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| Nov 23, 2012 | Nov 29, 2012 |
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| Nov 30, 2012 | Dec 6, 2012 |
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| Dec 7, 2012 | Dec 13, 2012 |
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| Dec 19, 2012 | Dec 19, 2012 |
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Parts List and Costs
| Item | Source | Cost Ea. | Qty. | Total |
|---|---|---|---|---|
| ARM7 NXP LPC2148 Microcontroller | SJValley Engineering | $60.00 | x1 | $60.00 |
| Batteries - 1.5V Size AA | Costco | $1.33 | x5 | $6.65 |
| Distance Sensor* | SJValley Engineering | $25.00 | x3 | $75.00 |
| LEDs | HSC Electronics | $0.35 | x2 | $0.70 |
| Motion Sensor* | Preet Kang | $9.95 | x1 | $9.95 |
| Motor Controller - 5A* | SJValley Engineering | $17.99 | x2 | $35.98 |
| New Bright Land Rover RC Car | Fry's Electronics | $15.34 | x1 | $15.34 |
| Piezo Buzzer - 75dB | RadioShack | $3.89 | x1 | $3.89 |
| Voltage Regulator - LM7805CV | HSC Electronics | $2.00 | x1 | $2.00 |
*provided by Dr. Ozemek and Preet Kang
Design and Implementation
Hardware Design
Frame and Inner Placement
For convenience, a New Bright toy RC car was purchased and disassembled. The motors and wheels were already pre-mounted onto the chassis, allowing electronic parts to control the car. On the chassis, slots above the wheel wells were large enough to house motor controllers while the center of the chassis provided enough room to include a small breadboard and the microcontroller. All wires were shortened to the shortest length possible to reduce clutter.
Sensor Placement
The sensors, which guided car control, were strategically mounted in front and above the car. This increased visibility of the sensors. Three distance sensors were used to detect obstacles: a left-, a center-, and a right-side sensor was used to determine steering of the vehicle. A front-mounted sensor would seek motion as the car was stopped. Should motion be seen, the piezo buzzer sitting at the front of the car would promptly be sounded.
Power Supply
The battery box beneath the car provided additional convenience. It housed five 1.5-volt AA batteries that supplied up to 7.5 volts in series. This power supply provided enough power to run all of the components of this project. Whenever existing batteries began to run low on power, new batteries could be swapped into place easily. The following list describes the power requirements of each part used:
| Part | Voltage Range | Source |
|---|---|---|
| Distance Sensors (Parallel) | +5V | Microcontroller Pin |
| LPC2148 Microcontroller | +7V to +20V | Battery Pack |
| Motion Sensors | +5V to +12V | Battery Pack |
| Motor Controllers | +7V to +30V | Battery Pack |
| Piezo Buzzer | +3V to +6V | Microcontroller Pin |
Hardware Implementation
Software Design
Software Implementation
Testing and Technical Challenges
Battery Life
By far, the battery pack is the most vulnerable component in keeping the Evil Watchdog alive. Only five 1.5-volt AA batteries power the entire system. Possible solutions to this problem are to either use batteries with longer lifespans or to use rechargeable batteries to avoid wasting single-use cells. During testing, a variable-voltage DC power supply, grabbing power from a wall outlet, was used to power the project. This saved battery power later needed for demoing.
Vehicle Weight
The original toy car was designed to carry a lightweight circuit board that received RF signals to control the motors. When the car is torn apart and new components are added for this project, the amount of weight placed on the wheels rapidly increases. Additional weight requires extra torque from the wheels to move the carried load, which can drain the batteries much more quickly. The best way to alleviate this problem is to eliminate excess weight and to select the lightest available parts to be placed on the vehicle.
Conclusion
References
Thanks To...
- Dr. Haluk Özemek
- Preet Kang, TA
Appendix
- Project Code: (FIXME)
- Project Video: (FIXME)
