Electronic Door Lock by Danny Howcroft

Door Lock

I have recently finished my A levels (one of which in electronics) and I thought I may share with you my As project. This is an ideal project for students or just for beginners to the world of electronics. Obviously all parts can be bought from Technobots.
I got a grade A with this circuit although I am not promising this will get anybody else the same grade!!! and do not use this to protect your property I am not liable!!!
Digital Door Lock:
This project introduces basic CMOS Logic and even soldering (If your feeling Brave).
Door Lock Circuit
Parts List:
  • Bread Board or strip board ( I suggest you try this first on bread board then transfer to strip board)
  • 4 x Tactile Switches
  • 4 x 1 Kohm Resistors
  • 1 LED or Relay (its up to you)
  • 5 volt battery pack
  • 4017 decade counter
  • 4071 AND
  • 4072 Quad input OR
  • Wire
  • Wire strippers / cutters
  • pliers
  • Soldering iron and solder

Door Lock Kepad

Door Lock Logic Board

Final Notes:
Where I have used the LED feel free to changes this to a relay or even a shoot bolt to suit any purpose. But remember when using a relay always use a protection diode!

Designer: Danny Howcroft



28/09/2010, 07:54

"Revised circuit from Danny now uploaded."

27/09/2010, 12:47

"Well observed, this must have been one of the earlier drawings I did. I will contact TechnoBots with an updated drawing
Thanks Danny.

27/09/2010, 01:43

"Well done Danny - great effort - but if you don't want to fry the 4017 you should put a current limiting resistor in series with the LED. Also as drawn, SW2 doesn't appear to do anything for living and SW3 drives two inputs."

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