Transcript Critical Design Review

Final Presentation
Group 16
Mike Orr
Loc Truong
Dang Khoa Le
Mechanical
Brake
Camera
Electronics

Interested in robotics and wireless control

To create a useful product
◦ Help the elderly and/or disabled

Assist in day-to-day activity of user

Durable
◦ Battery over-charging protection

Low cost






Weight less than 50 pounds
Be able to support up to 200 pounds of
weight (manual)
Travel no faster than 3 miles per hour
Have no more than a 2 second delay in video
streaming and control
Be able sustain functionality up to 40 meters
away from the walker
Be able to sustain functionality for up to 2
hours without recharging (non-continuous
use)
2” color display
DPDT
Switches
2.4 GHz
Video
Receiver
Receiver
HT12E
4 Channel
Encoder
433 MHz
RF
Transmitter
Remote Controller
M1
2.4 GHz
Video
Transmitter
Remote
Controller
L293D
Dual H-bridge
Motor Driver
M2
433 MHz
RF Receiver
HT12D
4 Channel
Decoder
Receiver
Left Motor
Motor Controller
Right Motor


Using Bridge Motor Drive L293D (16 PIN chip)
Cost : $2.50. Used for DC or Stepper Motor


Forward and Backward
Turning left and right





Produce high torque
Have reasonable turn speed
Require 12V DC (to be compatible with
system voltage supplier)
Generates low current to reduce heat
Low cost
Motor
Names
Voltage
(V)
Current
(A)
Torque
(N*m)
RPM
Cost
(USD/piece)
Electric
Gear Motor
12
3-15
11.5
50
59.99
63ZYT01C
DC Motor
24
4.5
1.3
2800
18
Leeson
M1135246
12
0.23
17.51
83
347
ON/OFF switch
Momentary switch
Latch Switch
Voltage source
12 V
12 V
12 V
Current rating
15 A
3A
3A
Control method
On - Off
Hold right : turn
Release : stop
Hold left : turn
opposite direction
Release : stop
Press right : turn
Press right : stop
Press left : turn
opposite direction
Press left : stop
L293D
Motor Driver
Electric Gear
Motor(Left)
Electric Gear
Motor(Right)




Motors connect
to small discs.
Pulleys connects
to the fixedwheels using
low-tension
belts.
Small pins are
used switch
from remote
control to
manual use.
When using
remote, the pins
will connect the
motors to the
plastic pulleys.
Parameters
Transmitter
Receiver
Operating Voltage
3V-12V
5V (±0.5V)
Operating Current
40mA (12V)
9 mA (3V)
5.5mA (5V)
Modulation Mode
ASK/OOK
OOK/ASK
Frequency
315MHz -433.9 MHz
315MHz-433.9MHz
Transmission Power
25mW (315MHZ at 12V)
Operating Range
120ft (clear of
obstructions)
--same
Feature:
• Operating voltage 2.4V-12V
• Built-in oscillator needs only small
value external resistor
• Low power and high noise immunity
CMOS technology
• Low standby current: 0.1µA (typical) at
VDD=5V
• Capable of encoding and transmit 12
bit of information:
o 8 address bits
o 4 data bits
• Easily interface with RF Transmitter
• Minimal external components
Feature:
• Operating voltage: 2.4V~12V
• Low power and high noise immunity
CMOS technology
• Low standby current
• Capable of decoding 12 bits of
information:
o 8 address bits (binary address
setting)
o 4 data bits
• Built-in oscillator needs only 5% resistor
• Received codes are checked 3 times
• Easy interface with an RF receiver
• Minimal external components
• HT12D decoder will be in standby
mode initially. Oscillator is disabled at
this point
• When the decoder receive data from
the encoder through the RF receiver,
Din goes high and it activates the
oscillator.
• The device starts decoding the input
data, which consists of 8 address bits
and 4 data bits
• The decoder matches the received
address 3 times continuously with the
local address given to pin A0 – A7.
• Once confirmed, the data bits are
decoded and activates 4 output pins
D8-D11.
• Rotation of the motor changes by switching its polarity
• To switch/control the polarity of the motors from the remote
controller, 2 DPDT switches are used
L293D Output Terminals ( Motor Input Terminals)
Motion
Forward
Reverse
Left
Right
Stop
+ Motor 1
- Motor 1
+ Motor 2
- Motor 2
1
0
0
1
0
0
1
0
0
0
0
1
0
0
0
1
0
1
0
0

Foscam FI9821W
◦ HD Quality, 1280x 720 Resolution
◦ High Cost

TENVIS JPT3815W
◦ Lesser Quality
◦ Good Pricing

Q-SEE Security Camera
◦ Good Quality
◦ RCA Compatible
◦ Free of Charge (Loc)

2.4 GHz Wireless Video/Audio Module
◦ 9 Volts
◦ Max Current:
 180mA (Receiver)
 30mA (Transmitter)
◦ Frequency: 2.4 GHz
◦ RCA Connectors
Remote Controller Block Diagram
2” color display
Power
Control
Video
2.4 GHz
Video
Receiver
9V
Battery
UA7805
Regulator
DPDT
Switches
HT12E
4 Channel
Encoder
433 MHz
RF
Transmitter
Receiver Block Diagram
433 MHz
RF Receiver
12V
Battery
Regulator
(5V)
HT12D
4 Channel
Decoder
Power
Control
Video
M1
L293D
Dual H-bridge
Motor Driver
M2
2.4 GHz
Video
Transmitter

3 options:
◦ HitLights Rechargeable 3800mAh Lithium Ion
Battery Pack
◦ Pitsco TETRIX 12-Volt Rechargeable NiMH Battery
Pack and Charger
◦ NiMH Battery Pack: Customize 12V 5000mAh

μA7805CKC
◦
◦

Internal Thermal-Overload Protection
High Power-Dissipation Capability
LM7809
◦
◦
Short Circuit Protection
Thermal Overload Protection
Device
HT12E
HT12D
RF Receiver
RF Transmitter
L293D (1) - chip
L293D (2) - chip
Left Motor
Right Motor
Video
Transmitter
Video Receiver
Camera
Video Display
Voltage (V)
5
5
5
5
5
5
12
12
Current (mA)
5
5
5
5
0.1
0.1
2400
2400
Power (mW)
25
25
25
25
0.5
0.5
28800
28800
9
9
12
9
30
30
600
216
270
270
7200
1944
Total Power:
67.385 Watts
3800
---------------------------5696.2
0.467 Hours*
*calculated for all components running constantly at
maximum ratings

Power
◦
◦

Max Weight Supported
◦
◦

Driving – 25 pounds
Stationary – 200 pounds
Speed (Max vs Avg)
◦
◦

Constant running motor
Varying on/off
Max < 3 MPH
Avg = 0.77 MPH
Video – tested at subsystem level

Thermal Issues
◦ Motor Driver reaching thermal threshold
 Use 12V relays to drive motors

Mechanical Issues
◦ Platform causes stability issues
◦ Wheel drive limits weight support capability
 Redo platform

Antenna
◦
Limits transmission range

Need longer antenna
Item
Unit Price
Ordered
Price
Video Transmitter/Receiver
$32.00
1
$32.00
RF Transmitter/Receiver
HT12D/HT12E
UA7805CKCS
LM7809
$4.12
$0.49
$0.67
1
1
1
1
$4.12
$0.00
$0.49
$0.67
Pitsco TETRIX 12-Volt
Rechargeable NiMH Battery
Pack and Charger
Video Display
$84.90
$42.31
1
1
$84.90
$42.31
22 pF capacitor (30pk)
$2.43
1
$2.43
QSEE Security Camera
FREE
1
$0.00
Wondermotor 12V DC Gear
Motor
L293D
DPDT Switches
PCB
$59.99
$2.50
$5.00
$48.36
2
2
2
2
$119.98
$5.00
$10.00
$96.72
Miscellaneous (bolts,
screws, welding etc)
$100.00
1
$100.00
Total
$498.62