|All the information you need to build a simple keypad code-operated switch - using cheap off-the-shelf components. |
This is a photograph of the Keypad Switch No.2 . It's a simplified version of the Universal Keypad Switch . The design has been modified to reduce the complexity of the circuit - and the number of components required. As a result - the code is somewhat less secure. However - there should be lots of situations where it will still be adequate.
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