Spring 2018 AT-ST Power Budget

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By: Joseph Cho (Mission, Systems, and Testing)

Verified By: Intiser Kabir (Project Manager)

Approved By: Miguel Garcia (Quality Assurance)

Table of Contents

Update: Figures have been updated to measured values.

Introduction

Power budget of the AT-ST project will be estimated using the power budget general template. The power budget will be estimated to determine the battery that should be used on the AT-ST. All of the values used in the power budget are measured using a current meter.

List of Parts

This is the list of all of the parts we are using as of today!

  • 3DoT Board
  • Bluetooth: HM11
  • Dual Motor Driver: DRV8835
  • (2) Motor: 50:1 Micro Metal gear motor
  • (2) Servos: HTX900
  • (2) Shaft Encoders : Pololu product 3081
  • I2C Expander: TCA9548A
  • Gyro : GY-521 (MPU6050)
  • Ultrasonic: HC-SR04
  • IR LED 1 (rated for 16~18mA)
  • Light sensor 1: Si1145
  • IR LED 2 (rated for 16~18mA)
  • Light sensor 2: Si1145

Power Budget Spreadsheet

Figure 2: The total Power In/Output of the system

Figure 3: Boost Parameters

Figure 4: Margin Calculation

Description

The current design for AT-ST uses 2 motors and 1 servo. The majority of the power is consumed by the motors and servo to move the AT-ST. The motors output power will be distributed by the motor driver. Four sensors will be used: UV, ultrasonic, shaft encoder, and gyroscope. The sensors will be using less power compared to the motors. Based on the estimated current consumption, a general power usage will be estimated using the power budget general template.

Measuring Current

Figure 5: Multimeter used to measure current

Description:

Rigol DM3058E digital multimeter was used to measure the current drawn by the components. The multimeter was tapped between the output pin of the microcontroller and VCC of the sensor.

Resources

  1. https://www.arxterra.com/news-and-eventsmembers3dot-robots3dot-goliath/
  2. https://www.sparkfun.com/datasheets/Components/LED/YSL-R547P4C-E3.pdf
  3. https://docs.google.com/spreadsheets/d/1WsdFps31TaSi-vaA3mB8fVlLQd3yEO-VCvbinQXoAG8/edit?usp=sharing
  4. https://docs.google.com/spreadsheets/d/1OaWtFrqYVQsylEh2nXOvKjFT-g2KG72ej-pF6OJWQ54/edit?usp=sharing