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How to Build Your Own Anemometer Using Reed Switches, Hall Effect Sensor and Some Scraps on Nodemcu. - Part 1 - Hardware

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Step 3: Connections to and From CD4051 Multiplexer

Picture of Connections to and From CD4051 Multiplexer
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CD4051 Analog Multiplexer


Multiplexers are combinational circuits with several inputs and single data output. They are equipped with control inputs capable of selecting one, and only one, of the data inputs to allow their transmission from the selected input to said output.

If you do not know the operation of the CD4051 I recommend reading the datasheet that you can find on the web. In summary, the 4051 has 8 analog inputs numbered from 0 to 7, 3 and pins A, B, and C that combined allow to read the inputs and define which analog output is being connected. At each reading, the software analyzes which connections are with positive current and will indicate the corresponding direction of the wind. This will be explained in detail in part 2 of the post. Look at the diagram to see how the rosetta is connected to the multiplexer.

Connections to Nodemcu

We will need 8 cables to connect the Nodemcu. See the diagram.

1 pair of positive (red) and ground (black) wires that supply current to the rosetta

1 pair of positive (red) and ground (black) cables that supply current to the CD4051

1 cable for analog output A0 (gray)

1 cable for digital input of pin A = D5 (blue)

1 cable for digital input of pin B = D4 (green)

1 cable for digital input of pin C = D3 (yellow)

I used a 10-wire telephone cable of different colors to facilitate the final assembly.

Identify each of the cables with their corresponding address to facilitate the final assembly.