diff options
| -rw-r--r-- | doc/report/report.tex | 22 |
1 files changed, 19 insertions, 3 deletions
diff --git a/doc/report/report.tex b/doc/report/report.tex index 400242f..c7cf533 100644 --- a/doc/report/report.tex +++ b/doc/report/report.tex @@ -28,6 +28,8 @@ \begin{document} \maketitle +\thispagestyle{plain} % enable page numbers +\pagestyle{plain} \begin{abstract} TODO @@ -96,17 +98,31 @@ While this may appear to provide redundancy, it in fact does not. On the contrary, it reduces reliability and increases complexity by introducing additional failure points into the system. A properly engineered solution would integrate the gauge into the EMS, allowing them to share sensor data, thus reducing the complexity of the system. -This brings us finally to the subject of this paper: a device that allows analog gauges to be retofitted into a car while leveraging the capabilities of the CAN bus already present in the vehicle. +This brings us finally to the subject of the paper: a device that allows analog gauges to be retofitted into a car while leveraging the capabilities of the CAN bus already present in the vehicle. TODO: outline. \section{Project Overview} -TODO +At a high level, the device acts as an interface between the car's EMS and the analog gauges in the cabin. +It receives sensor data encoded in CAN frames from the ECU, and transforms them into signals that the gauges can understand: such as a variable-frequency square wave for a tachometer, or a 0--5V analog signal for a pressure gauge. +Thus, it is referred to as an \emph{analog gauge driver with a CAN interface}. + +A block diagram of the system is shown in Fig. \ref{fig:BlockDiagram}. +The device has a CAN controller and transceiver for sending and receiving CAN frames. +A microcontroller decodes and extracts sensor data from the frames, and communicates the data to the peripherals which drive the gauges. +Two dual DACs (digital-to-analog converters) generate signals for the four analog outputs. +These can drive up to four temperature or pressure gauges, or any gauge that accepts a 0--5V analog input. +The microcontroller's timers produce two variable-frequency square waves which drive the tachometer and speedometer. + +As it is intended to be a generic part that can be retrofitted to existing cars, the device must work with any combination of sensors, gauges, and CAN encoding schemes. +Thus, it is user-programmable, allowing it to be installed in any system. +The user-configuration is programmed via CAN and stored in non-volatile memory, namely an EEPROM (electrically erasable programmable read-only memory) chip. +TODO: mention software/firmware and that it will be discussed in the subsequent sections, after the hardware. -\section{Objectives} +TODO: block diagram. TODO |