Automatic day night door

Discussion in 'The Projects Forum' started by gopalyajur, May 2, 2011.

  1. gopalyajur

    Thread Starter Well-Known Member

    Jan 3, 2010
    Hello all,

    A friend of mine asked me to help him design an automatic door which opens in the morning and closes in the evening. His design is in the pdf named "Autodoor- Circuit-1". I built the circuit for him and seems to work well. There are two limit switched which are placed close to the door to stop the motor when the door is completely closed and opened.

    As a first step I tried to redesign the circuit to eliminate the two additional relays and the modified circuit is shown in the pdf named "Autodoor- Circuit-2".

    I would highly appreciate if someone can help me with the following points

    1. are there any errors in the circuit I designed? Will it work like circuit my friend designed.

    2. In the night the relay 1 in both the circuit is ON. And the whole circuit consumes around 80 ma (with out the motor running). I would like to eliminate the relay completely. I would like to do so because my friend wants to use in an remote location and is using batteries. I know than an NPN transistor which is capable of handleing the current to motor (I use a geared 6V motor which consumes almost 1A.) can be used for an N/O condition. How can I do the same for N/C condition? Will a PNP transistor help? I am bit stuck.

    3. Are there any semi-conductor based relay which has N/C and N/O contacts which is also capable of handling the motor current.

    Thanks in advance.