In my thesis, an automatic lubrication system for motorcycle chains was designed and built. There are a variety of other solutions for the automatic lubrication of motorcycle chains, but most of them automatically lubricate at certain intervals; on the contrary my plan is based on the detection of the oiling condition.
I chose single-line lubrication system, due to its simplicity. It means that the device lubricates the chain through a single supply line. A PIC16F1788 microcontroller performs the control and regulation processes. I designed the hardware and the software of the system, and also built it on a testboard. The device is able to determine the lubrication level of a metal surface, and make up for it, if needed. Essential elements of the circuit are the PIC microcontroller, the solenoid valve, and the infrared transmitter and receiver for the detection. The solenoid valve, which is controlled via a bipolar npn transistor in grounded emitter circuit operates with 12 V supply voltage, and it is protected from dust and moisture that is an indispensable condition because of the close placement to the chain. If the solenoid valve is open, the lubricator oil comes to the surface that requires lubrication. A two-line LCD display and three buttons realize the connection with the user. A menu appears on the display, in which the user can select from the different operating modes (direct, timed, detection) and adjust some parameters with the buttons. To the detection of the lubrication level, the metal surface is illuminated with an infrared LED, and the reflected light is perceived with a phototransistor. Measurements and tests were carried out on the power consumption of the device, and on the A/D values and voltage levels of the sensor. I determined the different states of the lubrication based on the tests. In the case of detection mode the device compensates the interference from outside light with a calibration phase.