How to Make Simple and Low Cost Auto Water Dispenser

Hi guys, we will be showing you how to make a simple and low cost auto water dispenser.

MB-12 1-120s Timer Kit is designed to control the relay according to the user pre-set timer. By turning the on board’s potentiometer, the time timing can be adjusted by user. The 555 IC timer is configured in monostable mode which is also known as one-shot pulse. By tuning the potentiometer, the resistance of potentiometer will change. The changing of resistance will cause charging or discharging time of 555 IC timer. It is subsequently affect the time timing (pulse) generated by 555 IC timer. Thus, the relay can be controlled based on the time which is set by the user.

MB-15 IR Controller Kit is designed to control the relay by sensing the obstacle in front of the IR sensor. When there is obstacle in front of the sensor, the relay as output will be activated. In this kit, the LM358 operational amplifier is used as a comparator to compare voltage at the non-inverting input (+) and at the inverting input (-). When the voltage at inverting input pin (IR sensor) of the LM358 is higher than the voltage at non-inverting input pin (10k Ohm Potentiometer), the LED and relay will be turned on. The LED and relay will be turned off when the input voltage at inverting input is lower (IR sensor) than the voltage at non-inverting input. The LED and relay is turned on when the voltage from the IR sensor is higher than the pre-set voltage at the potentiometer. For the IR sensor pair, when an obstacle is detected by the IR sensor, the IR light from the IR transmitter will reflect to the IR receiver causing the resistance of the IR receiver to decrease. It results a low voltage at the inverting input. Once the inverting voltage is higher than the non-inverting voltage (adjustable by potentiometer), the relay will be triggered.

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