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Automated VCR Recording Control Device

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To design a device that obtains updated TV schedules information online, ... Online TV listings database. Periodic updating of selected programs. User-friendly ... – PowerPoint PPT presentation

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Title: Automated VCR Recording Control Device


1
Automated VCR Recording Control Device
  • Melvin Cheang
  • Ryan Mokos
  • Fall 2000 ECE 345 Project 9

2
Inspiration
3
Scope
  • Objective
  • Review Initial Design
  • Design Evolution
  • Testing and Verification
  • Concluding Remarks

4
Objective
  • To design a device that obtains updated TV
    schedules information online,
  • with the help of the PC software,
  • operates the VCR accordingly in recording TV
    shows.

5
Initial Hardware Design
  • Serial connection
  • Independent power source
  • IR communication with VCR
  • Clock
  • Memory
  • Micro-controller

6
Initial Hardware Block Diagram
7
Initial Software Design Flowchart
8
Initial Software Design
  • Online TV listings database
  • Periodic updating of selected programs
  • User-friendly interface
  • One-click programming
  • Search mode
  • Browse mode

9
Design Evolution
  • gt Hardware gt Software

10
Hardware Evolution
  • Micro-controller STAMP II
  • Memory RAMPack
  • Clock 2Hz Source Some STAMP code
  • IR Transmitter

11
Basic STAMP II
  • Features
  • 26 Byte Usable RAM
  • 2048 Byte EEPROM
  • 16 General I/O Pins
  • Power 7-8 mA
  • Chose it because of
  • Simplicity
  • Sufficient for Project Requirements

12
Basic STAMP II
13
Basic STAMP II
14
The RAMPack B
  • Serial interface
  • 8 Kbytes of RAM
  • Power
  • 1.5 mA / 80 mA

15
Linking the RAMPack to the STAMP
  • Communications set at 9600, N, 1

16
2Hz Source
Output
17
2Hz Source
  • 4060 14-Stage Counter
  • Power lt1 mA
  • STAMP need to be actively counting the pulses
  • counts 240 pulses and then increments the clock
    register by 1

18
Remote Control Failure
  • Tried direct 5 volts
  • Tried using SCR
  • Electro-mechanical relay?

19
IR Transmitter Diagram
20
IR Transmitter Diagram
  • 555 Timer Chip
  • Frequency 1.44 / ( RA 2RB ) ? CT )
  • 40 Khz
  • Input 1 ? Transmit
  • Input 0 ? Off
  • Power 6 mA \ 18 mA

21
Decoding the VCR IR Signal
  • IR Decoder Module from Radio Shack

Output to Oscilloscope

22
VCR IR Signal Success?
1 1 0 0 0 0 1 1 0 1 0 0 0 1 0
23
VCR IR Signal
  • Bit 1 1500 ?s gap
  • Bit 0 500 ?s gap
  • Problem 1 Cannot use STAMP SEROUT function
  • Problem 2 VCR does not respond

24
VCR IR Signal
25
VCR IR Signal
1 100001 1 0 10001 0 1 1 000
1001 0 1 1 1 0 1
68 ?s
  • Note Time between pulses is 68 ?s

26
VCR IR Signal Finally
  • Power Signal
  • 1st pulse 11000 0110100010
  • 2nd pulse 11000 1001011101
  • 3rd pulse 11000 0110100010
  • 4th pulse 11000 1001011101
  • Fitting IR signals coding into Stamp EEPROM

Repeated 1st and 2nd pulse
27
Device Schematic
Total Power Min / Max 16 mA / 107 mA
28
Device Operation
Simple Flowchart Overview
29
Software Evolution
  • Serial communication
  • Database
  • User interface

30
Serial Communication
  • Basic port-to-port communication
  • Hyperterminal
  • Separate, simple applications
  • Problems with receiving data using events
  • Integration into project
  • Echo problem

31
Database
  • Local Microsoft Access database
  • Retrieve information from simple table
  • Search for exact match only
  • Access program listings only once
  • Online SQL database
  • Simple interface
  • "SELECT Title,Channel,Start,Stop,ID FROM
    ProgramTable WHERE Title LIKE 'star'"

32
User Interface Search Window
  • One-click programming
  • One button per add slot in Search window

33
User Interface Review Window
  • One button per remove slot in Review window

34
User Interface Browse Window
  • One button per program in Browse window
  • Modify button size according to program length
  • Control arrays

35
Other Software Issues
  • Handshaking and data verification
  • Date representation
  • User-defined types

36
Testing and Verification
  • Time to program BASIC Stamp
  • Programming rate
  • Program capacity
  • IR transmitter range
  • Accuracy of 2Hz clock
  • Multi-program recording

37
Test Results
38
Actual Costs (including tax and SH)
  • RAMPack B
  • Remote Control
  • IR Detector Module
  • TLC555 Chip
  • STAMP II Module
  • Total
  • 33.88
  • 16.12
  • 3.86
  • 1.49
  • 52.20
  • 107.55

All other parts are obtained from the ECE parts
shop
39
Benefits to the Consumer
  • Automatically adjusts recording schedule with
    updates from the database.
  • With the original design using the universal
    remote, we would be able to interface with many
    brands and models of VCRs in every home.
  • Save the hassle of programming VCR manually.

40
Real World Limitation
  • Problem length of recording time limited to 6hr
    tape in extended play mode
  • Solution have the software calculate a time to
    remind the user when to change the tape.

41
Recommendations
  • Use a low-power RTC Chip with RAM, e.g. the
    Dallas Semi DS1302
  • Implement power-saving in STAMP code
  • Use the STAMP IISX with more EEPROM memory
  • Know programming languages before you use them

42
(No Transcript)
43
End of Presentation
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