Intelligent energy-saving water dispenser design plan

After the ordinary household water dispenser turns on the heating power, no matter whether there is anyone in the room or whether it is day or night, it is always in the heating and heat preservation state. The pure water in the heating tank is heated repeatedly for a long time, which is not only harmful to health but also quite harmful. Waste electricity. In view of the above shortcomings, the author modified the ordinary household water dispenser and used the principle of microwave induction to enable the water dispenser to automatically detect whether there are people moving in the room, and at the same time determine whether the people in the room are passing by briefly, and then automatically control the heating function, so that the water dispenser has Intelligent and power-saving functions.

Working principle: The newly added components in the figure include the power supply part, which is a typical capacitor step-down circuit composed of Cl, C2, Rl, DW, and D, which provides stable llV DC voltage to the TX982 and 555 time base circuits. TX982 is a microwave induction controller. It contains a microprocessor and uses the microwave Doppler effect to establish a micro-electric field in a certain space. When someone or a moving object enters the electric field, it will reflect the echo and detect the polarity after mixing with the electronic circuit. A weak frequency-shifted signal, after intelligent processing, this signal can output a control signal. The effective monitoring radius of TX982 is 1~7 meters. The main reason why pyroelectric sensors are not used here is to consider the convenience of modification, and pyroelectric sensors are particularly sensitive to heat sources and are prone to malfunction. The microwave sensor controller can be detected as long as it is installed behind the plastic panel of the water dispenser without damaging the appearance of the water dispenser. The output terminal of TX982 adopts open-collector output. When the microwave circuit detects someone moving within the monitoring range, the internal transistor is turned on for 10 seconds to discharge the charge on C3. The 555 circuit forms a monostable delay circuit. When pin 2 is lower than 1/3 of the power supply voltage, pin 3 outputs high level, the relay is closed, Kl turns on the heater for heating, and the delay time composed of R2 and C3 It is 3 minutes, and the delay time is set relatively short. If people only pass by briefly, the water dispenser will automatically stop heating after 3 minutes. If there are always people in the room, TX982 will trigger the monostable circuit multiple times within the delay time. When working, the water dispenser will continue to heat until it reaches the set temperature.

If you want to further improve the energy saving effect, you need to make some small modifications to the heating tank of the water dispenser. The insulation measures for most water dispensers are very simple. They only use two pieces of preformed foam plastic to surround the heating tank, so the heat dissipates quickly. It is best to use polyurethane material (generally produced by manufacturers of solar water heaters) to foam and fill on-site around the heating tank. This treatment can ensure that there is no gap between the insulation material and the heating tank, and reducing air flow can greatly improve the insulation effect. .