Range-Finding Rear-Collision Accident Prediction and Warning For Motorcycles with Integrated Signal Vest
The two main parts that make sensor is the laser diode and the avalanche photodiode. The laser diode that was chosen is OSRAM's SPL LL90_3, which has the listed applications of range finding, security surveillance, illumination, and testing measurements. This part has been designed to project 905 nm wavelength across long distances. There is an internal MOSFET transistor to use as a trigger so that a microcontroller can control the laser diode. The diode can be ran off of 5V, but to get the range that will be required, voltage above 10V will be needed. The actual voltage will be determined once live voltage trials can be ran. The second part is the avalanche photodiode, Marktech's MTAPD-06. The photodiode is also designed for optical rangefinders, along with high speed optical communications, medical equipment, and bar code readers. Excluding the last two applications, this device is designed for long range detection. In order to turn the current that the avalanche photodiode allows through into voltage, a transimpedance amplifier will be needed. Once the current has been transformed into a voltage, it must be rectified into a positive voltage that will indicate the sensors detection of light. The way that the sensor will be able to time the flight of the light pulse will come from a time-to-digital converter (TDC). The TDC to be used is Texas Instruments TDC7200. The chip will time how long it takes for the light to travel from the laser diode to the avalanche photodiode, then send the information over SPI communication protocol to the controlling microcontroller. This is how the sensor will work wit the given parts.