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Better Than a Bubble Stick. Alex Bork, Justinas Lialys, Laurynas Lialys, Tony Srimongkolkul. What is it all about?. Make equipment’s do not fall off the stage Assist in leveling Apex stages in any environment Expedite stage deployment. What is this? How does it work? .
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Better Than a Bubble Stick Alex Bork, Justinas Lialys, Laurynas Lialys, Tony Srimongkolkul
What is it all about? • Make equipment’s do not fall off the stage • Assist in leveling Apex stages in any environment • Expedite stage deployment
What is this? How does it work? Our Accel. has 3 axis, so this operation is performed twice to yield pitch and roll
This Hobbyist Accel. has terrible resolution! • Main issue is “simple” sampling yields very few values to represent a large range of spatial orientation • Two Fixes • Each axis has a voltage range ~700 mV with an offset such that the max voltage is ~2.8V • ATMegas have a pin to define the voltage range the 1024 values represent, (ground to AREF), so feed it 2.9V. That helps a little.
Oversample and Average Extra bits of resolution 10 bits = 1024 values. Averaging with a twist. • Take 1000 samples and add them = 1.024E6 possible values • A little less than a 20-bit ADC • Divide by 100 so we have an averaged variable ranging ~6000 values • As opposed to ~250 on the un-fancied 1024. • Map This 6000 from -1.000 to 1.000 • 1/1000’s of a g force for each axis. • This process may introduce significant rounding error. • Will noodle with. • HOO AH resolution better than 0.4°
Evaluation and Testing • Slave ATmega • Ensure that the values from the accelerometer are accurate and quantized appropriately (done) • Master ATmega • Observe if it can handle multiple tasks (code refinement) • Display ATmega • Displays characters that are appropriately associated with the slave Atmega (done)
This system uses voltage instead of current sensing. What happens if the voltage sags? • Higher DC voltage supplied down transmission lines to ensure minimum of 5.5V at input of each node. • Production model will use current sensing. As it is, the 3.3V rail for the accelerometer is run through two voltage regulators. • Water leakage in system • Seal the system with enclosure (future goal) • Vibration Tolerance • Screw and tighten ATmega down to handle short abrupt vibrations • EMC environment • Wireless trans-receivers might have interference with other electronics around (future goal) • Power Supply • Change battery configuration for appropriate voltage and lifetime • Temperature Handling • Enclosure acting like heat sink (not a problem, will be considered in future )
What’s been accomplished so far • Slave node Interface with the accelerometer established The angles have better than 0.5 degree accuracy • Master node Interface with one slave node established • Display node Displays data Communicates with Master node via simple serial connection
Prototyping Slave Node Master Node Display Node
Milestones • Phase 1: Accelerometer to Slave Node design(done) • Phase 2: Slave configuration to Master(done) • Phase 3: 3 Slave configurations to Master(in process/partially done) • Phase 4: Master design to Display and debug(In process/partially done) WE NEED OUR STUFF AND WE NEED TO LEARN HOW TO CODE MORE GOODER.