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Plug and Play Logic Gates

Most amateurs dream of having an intelligent system - one that does different things depending on different inputs, a computer which give the temperature, light, battery levels etc will turn on and off different things. To most people this is way too difficult or way too expensive. These "plug and play" logic gates hope to help to solve this.

Background

All modern computers are built from NAND gates. While this sound like a complex bit of jargon, it is most of the most basic logic principles. Like plus, minus, divide etc for decimal numbers, binary numbers (0 and 1, true and false, on and off) have OR AND and NOT, NAND being NOT AND. Eg 5 + 3 = 8, 1 AND 0 = 0. Believe it or not the processor in your computer (the bit that does the work) is thousands of very tiny NOT AND gates. Google binary logic if you want to understand this in more detail.

How does this help us? We don't need a super computer we just want a basic on and with a few logic gates we can build a basic one. For a basic example, I want my water pump to turn on we the voltage is above 12.4 V and then the float switch in my tank is on. We want two sensors and an AND gate.

Float Switch On Float Switch Off
Voltage Above 12.4V Pump On Pump Off
Voltage Below 12.4V Pump Off Pump Off

It doesn't seem like it but this is the most basic computer, and building these logic gates together can make some complex systems.


Logic Gates

How to Build an AND Gate
A nice and easy project that can be built from $5 up.
01
000
101
How to Build an OR Gate
A very easy project that can be built from $20 up.
01
001
111
How to Build an NAND Gate
Pretty easy but not as neat, built from $5 up and can run the world.
01
010
100

Sensors

Light Sensor
Float Sensor
Voltage Sensor
Counter
Clocks
Motion Sensor
Touch Sensor

Example Applications

  • Turn on water pump when the batteries are full.
  • Six hour night light
  • Water my plants every two days for 10 minutes
  • Turn on lights for 5 minutes when movement sensed.
 

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