EEL 4924 Electrical Engineering Design (Senior Design) Preliminary Design Report 25 January 2011 Project Name: Digital Dashboard Team Name: Uncensored Sensors Team Members: Name: Matthew Greenberg Email: matt8@ufl.edu Name: Brandon Kalarovich Email: bkalarovich@gmail.com Project Abstract: Our project is to design a digital dashboard for a motorcycle. We will replace all the gauges (except perhaps the analog tachometer) with a graphical LCD. The dashboard will include the standard features found on the original gauge cluster, like a speedometer, tripometer, odometer, and engine coolant temperature. Additional features we'd like to implement would be speed control, like that found in automobiles, vehicle telemetry data, and other sensors not found on this model of motorcycle, like oil pressure and oil temperature. Calculation based features (those not needing any additional sensors than what is listed above) will include a gear position indicator (using vehicle speed and engine RPM), and projected instantaneous MPG rating using throttle position and an engine load parameter. The tire size and front/rear sprocket ratio will be user customizable. This will allow the speedometer and odometer to remain accurate if the user decides to stray away from original manufacturer's settings.
2 Digital Dashboard Uncensored Sensors Table of Contents Project Features...3 Project Objectives...4 Concept/Technology Selection...6 Components...8 Distribution of Labor...9 Projected Timeline...9 List of Tables/Figures Project block diagram... 6 LCD module... 8 Distribution of labor... 9 Gantt chart... 9
3 Digital Dashboard Uncensored Sensors Project Features The objective of the project is to design a digital dashboard that will have many more features than an analog dashboard used in older motorcycles. Features include: Speedometer. Tripometer. Odometer. Gear position indicator. Engine Coolant temperature. Oil temperature and pressure. Customizable tire size and sprocket ratio settings Speed/cruise control Telemetry data (Lean angle, lateral/longitudinal acceleration rate). Projected instantaneous miles per gallon (MPG) rating
4 Digital Dashboard Uncensored Sensors Project Objectives We have a few performance criteria will need to meet, and other's we plan to meet. The most crucial criteria to meet are maintaining accuracy for the speedometer and odometer. The United States mandates an allowed error of 5%. The United Nations Economic Commission for Europe (UNECE) mandates that a speedometer should never read slower than the vehicle is moving, and allows up to 110% + 4 kmh error from true speed for common speeds. The factory speedometer from Yamaha reads about 110% from true speed. This was proven by experiment using multiple unique speed stations found on the interstate (the speedometer would read 80 mph, and the speed station would display 72 mph). The speed control feature will need to be capable of being turned off if a failure occurs with the device. This will require the speed control portion of the device to have direct access to the clutch and brake control signals. Accuracy in additional sensors will also be desired; however because they are only for display purposes only, we feel they can have a tolerance of a few percent. Additional performance specifications we would like to meet would be to have the display updated at 0.5 second intervals. This would allow up to date vehicle data, without a refresh rate that may be too high and cause ghosting of numbers, which may become evident in colder temperatures. Because a motorcycle is a small vehicle with space constraints, our device will need to be kept as small as possible, however removal of the existing dashboard will supply additional space. The parts that are
5 Digital Dashboard Uncensored Sensors required to be in the gauge cluster area are of small volume. Overall, we believe that the space constraint is not a very strict requirement.
6 Digital Dashboard Uncensored Sensors Concept/Technology Selection Figure 1: Device Design Block Diagram Our device will be divided into 4 sections: the Host up, the Display and Basic Features (Display) up, the Speed, Mileage, and Speed Control (Speed) up, and the Telemetry and Additional Vehicle Data (Data) up. The purpose of utilizing a multiple microcontroller design was to manage interrupts. Because most motorcycle ignition systems use a wasted spark design, the tachometer signal is triggered every engine revolution (as opposed to every 2 revolution like a typical automobile engine). This means that the tachometer interrupt can be called up to 13,000 times per second. After doing some math, I figured the Hall Effect sensor interrupt can be triggered up to 2,000 times per second. Because we wish to maintain accuracy for the Hall Effect sensor, we decided to separate the two into different microcontrollers. Another reason for multiple microcontrollers was pin control. Because of the large number of sensors and ADC's required, multiple microprocessors allow us to use many cheap up instead of one large up.
7 Digital Dashboard Uncensored Sensors The various features will be implemented as follows: 1. The speed and mileage calculations will be done using pulses from a Hall Effect sensor over a set time in US and metric units. 2. The instantaneous MPG rating can be calculated with the throttle position and engine load parameters. 3. Temperature sensor will be used to calculate engine coolant temperature. 4. The gyroscope and accelerometer will be used to calculate the telemetry features such as lean angle and lateral/longitudinal acceleration rate. As seen in figure 1, the data from the sensors and the motorcycle itself such as the brake and clutch signals will be converted into digital form using the Atmega324p A/D converter, and then transmitted to the host microcontroller with interrupts. The host microcontroller will place the data into a buffer and transmit it to the display microcontroller where it will then be displayed on the graphical LCD.
8 Digital Dashboard Uncensored Sensors Components We will use a large graphical LCD or possibly two smaller LCDs to display all the motorcycle data (similar to Figure 1). For user input, 4 pushbuttons will be used so the user can select through various options and telemetry data. Our full design will require at least 4 microcontrollers; however because the calculation load is divided amongst all microcontrollers, we will be able to use cheaper, less powerful microcontrollers. We plan to use Atmel Figure 2 Possible LCD module to use, 2.76 in. x 2.04 in. area. http://www.crystalfontz.com/product/cfaf320240f- T#photos microcontrollers. For development, we will use the Atmel ATmega324P because of its large number of I/O ports, 1 KB of built-in EEPROM, and included peripherals (SPI, UART/USART, etc.); however, after the device has been prototyped, we may be able to use smaller versions of the ATmega microcontrollers family for reduced cost and volume. If the desired sensors are not already available on the motorcycle, then those sensors will need to be purchased. This will include the Hall Effect sensor, gyroscopes, accelerometers, and oil temperature/pressure sensors. Typically this device will be used while the vehicle's engine is running, so power will be readily available. We plan to use DC-to-DC power converters to supply power to our electronics. We will seek a power converter that allows a range on input voltages from +9 V to at least +14.4 V (the typical voltage range supplied by the vehicles charging system) and the output voltage to be +3.3 V to +5 V, depending on the requirements for chips we use.
9 Digital Dashboard Uncensored Sensors Distribution of Labor Matthew Greenberg Brandon Kalarovich Research 50 50 Board construction/ soldering 60 40 Testing/Debug 50 50 Software 50 50 Hardware 40 60 Figure 3: Approximate distribution of tasks, subject to change. Gantt Chart Figure 4: Projected timeline of the project, subject to change. Figure 3: Work schedule.