1 / 31

Smart Battery System Monitor

This system installed in a car monitors the voltage and current from the lead ... Audio alert in car and to wireless receiver to warn of significant battery drain ...

Télécharger la présentation

Smart Battery System Monitor

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.


Presentation Transcript

  1. Smart Battery System Monitor ECE 445 Group 3 Jason Hoban David Atwood

  2. Introduction • This system installed in a car monitors the voltage and current from the lead-acid battery. • Prevents accidental battery depletion • Ensures car ignition capacity is maintained • Preserves the life of the battery

  3. Features • Real-time voltage and current monitoring to display battery voltage level and battery life remaining • Audio alert in car and to wireless receiver to warn of significant battery drain • Automatic cut-off of system loads to ensure ignition level charge remains • Simple one push reset to transfer control back to user

  4. Overall System

  5. Original Schematic – Car Side

  6. Original Schematic – RX Side and Load Switch

  7. MSP 430F156 • Reason for Selection • Low Power Consumption • High Functionality • 2x ADC, DAC, UART, Multiple Digital I/O • Size

  8. DC-DC Conversion • LM317 – 3 Terminal Adjustable Regulator • TX Side • 12 Volts to 3.3V and 5V • RX Side • 9 Volts to 5V DC-DC Schematic

  9. DC-DC Tests Transmitter Side Receiver Side

  10. Current Sense Module • LTC6101:High Voltage, High-Side Current Sense Amplifier • Precision .005Ω Sense Resistor Current Sense Schematic

  11. Current Sense Gain Tests

  12. Voltage Monitoring • Original Design • MAX6652 – Temperature Sensor and System Monitor • Revisions • Resistive Divider • Differential Amplifier Op-Amp Design Op-Amp Schematic

  13. Voltage Monitoring Tests

  14. Buzzer and Pushbutton • Piezoelectric Buzzer • Pushbutton De-bouncing Circuit Circuit and RC Equation

  15. Pushbutton

  16. De-bounced Pushbutton

  17. High Power Load Switch • High Ic rated NPN BJT • Smaller NPN BJT to drive the base • Controlled by MCU • Loads cut when Battery <= 11V Original BJT Switch Set-up

  18. BJT Design Constraints • HP BJT must be operated in saturatation • Initial tests show base current of at least 50mA required to drive base (VB=3.3V and IB = 50mA yields VCE = 210mV) • MSP430 I/O should not exceed 6mA • MPS2222 BJT rated at Ic,MAX = 600mA • Voltage from MSP430 must have enough headroom to operate all transistors at VBEON but not exceed current limit of the MPS2222

  19. Final Switch Set-Up • VOUT from MSP430 = 2.25V achieves IB,Q1 = 6mA • On-chip DAC required • Q1, Q2 drive 300mA into base of Q3 • Saturation achieved as evidenced by VCE,Q3 = 124mV and VLOAD = 11.79 V for a 11.95 V Battery Source Final Schematic

  20. TX/RX Circuit • LINX 416-ES Transmitter and Receiver • Design Changes • Frequency to Voltage Converter • Uses Transistor to Draw Required Current

  21. RX PCB • Created PCB • Issues with Incorrectly drawn trace and grounding • Scrapped to Proto Board

  22. TX Data Transmission

  23. LCD • PC-1602-Q 2x16 LCD with BPI-216 Serial Backpack • Serial RS-232 • Inversion Transistor required for UART output

  24. LCD Data Transmission

  25. Overall Power Determination

  26. Overall Power Consumption

  27. Successes • Interrupt Routine • Cutting off of loads • Pushbutton Reset • MSP Coding • Less readily available information than more common PIC Microcontroller option • LCD Display • Struggled with RS-232 and timing issues at first • Lack of Crystal at Deadline

  28. Challenges • I2C Code • Abandoned due to software issues and time constraints • ADC functionality allowed for Op-amp solution • TX/RX • Transmission Worked with Power Supply on Proto Board but full scale implementation created problems • PCB Issues

  29. Recommendations • With more time system could have been further optimized and expanded • MSP operation in Low Power Mode is made possible by sourcing clock from external 32kHz crystal • Further Research into using components with lowest power drain (i.e. instead of available LCD) • PCB Board Design could be greatly reduced in size • I2C Chip offered temperature monitoring • Time left Equation could be improved • Battery drain is not strictly linear • Averaging could produce more stable time left display

  30. Acknowledgements • Teaching Assistant Paul Rancuret • Professor Gary Swenson • Mark Smart and everyone else in Parts Shop • Professor Philip Krein • Texas Instruments for MSP Debugger Donation

  31. Questions ?

More Related