1 / 12

P10002 Dynamic Keyboard

P10002 Dynamic Keyboard. Alexander Moulton Marie Hammer Xingwang Gao Andrew Robertson Team Lead Mechanical Engineer Electrical Engineer Electrical Engineer. Project Goals. The purpose of this project is to capture key-strike dynamics for integration into a full keyboard

hanley
Download Presentation

P10002 Dynamic Keyboard

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.

E N D

Presentation Transcript


  1. P10002 Dynamic Keyboard Alexander Moulton Marie Hammer Xingwang Gao Andrew Robertson Team Lead Mechanical Engineer Electrical Engineer Electrical Engineer

  2. Project Goals • The purpose of this project is to capture key-strike dynamics for integration into a full keyboard • Enhance text based communication by providing an analog signal in parallel with binary keystroke data • Accurate differentiation of typing forces applied • Encapsulate typing forces with keystroke data and communicate with a PC • Characterize human typing forces for future projects

  3. Revised Project Goals • Original project goal: • capture emotion while typing • Complications: • Keyboards are binary devices • Users are not trained to pay attention to how they type • Revisions: • No association between emotion and typing patterns • Conscious user input expected

  4. Customer Needs and Specifications

  5. Design Concept - Electrical • Analog data acquisition is independent of the original keyboard design • Four stages: • Thin film pressure sensitive device acts as a variable resistor in a voltage divider • Conditioning circuitry • Analog to digital conversion • Communication

  6. Conditioning Circuitry Micro Controller

  7. Design Concept - Mechanical • Keys: scissor switch, buckling, dome spring • Materials: ABS plastic, silicone, foam • Methods of Manufacturing: re-fabrication of current keyboard, rapid prototyping with ABS plastic, injection molding, machining raw material

  8. Test Plan • Sensors have a static output (i.e. no capacitive loads) • Load a sensor with a static weight and measure any variation in the output over time • Establish a voltage output linearly proportional to force applied while typing • Calibrate device output (Voltage vs. Force) using weights ranging from 100g (~1N) to 2kg (~20N) • A linear best-fit line should be possible • Force transmitted through the key to the sensor matches the force applied at the top of the key within ±10%. • Calibrate the device output with and without the key and spring • Output of key strikes must be independent of simultaneous key strikes • A test key is loaded with a static force while a second key is fully depressed • The variation in output voltage with and without the second key being pressed is measured • Characterize human typing force • Objective is to establish a baseline of normal typing force for future reference • Result are compared with results from previous studies in typing force (1N to 2N) to ensure device accuracy • determine the resolution of human typing force • Objective is to determine the minimum amount of force a user can consistently increment • Tap key with successively increasing force average difference between keystrokes is measured

  9. Test Data Modified: y = 0.002701 - 0.046 Unmodified: y = 0.002477 + 0.148 %errorm = (0.002701 – 0.002477)/0.002477 * 100% = 9.04% ΔV << Vmax/(# of output partitions) 31mV << 3.7V/8 = 462mV Variation in output voltage for 1, 5, and 10N test forces with a second key fully depressed

  10. Test Data (cont.)

  11. Meeting Specifications • Establish a voltage output linearly proportional to force applied while typing - PASS • Couple analog data with keystroke character - PASS • System is able to measure a large range of input force - PASS (0 to 13N) • Users are able to establish up to 8 distinct outputs while typing – Not met, only 6 levels were achieved • Use sensors with static output - PASS • Output is independent of simultaneous keystrokes – PASS • USB protocol used for communication - PASS • Applications able to monitor USB port can be programmed to interpret and display the data received - PASS

  12. Future Project Recommendations • Printing Force Sensitive Resistors in a matrix underneath the keys for future keyboards • Designing modified keyboard to hold more circuitry as an alternative to modifying the keyboard.

More Related