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  • Author Author: verrverr
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Pas Home / Home ventilation demo + cellar door demo

verrverr

Pas Home - Index

 

Hi, this week i finalize my proto for controlling my home ventilation. I'm not sure of the connection of the transistor.

 

Are the 2 diodes are useful? Is that the resistor R6 value is large enough ?

 

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The code for the python and nodejs application controling the RPiSoC is available here https://github.com/pascalmartin/ForgetMeNot/tree/master/bundles/rpisoc

And the openhab configuration here https://github.com/pascalmartin/ForgetMeNot/tree/master/bundles/openhab

 

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I also made my cellar door state detector with EnOcean contact sensor.Since there is not much light in the stair descent, I position the sensor sensor in a more enlightened place

 

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The wire was not long enough. I really need a tablet

  • Pascal

    Nice work, its coming together.

     

    re transistor, diodes.

    The diodes aren't achieving anything, BUT you could use a diode across the transistor (C-E) in reverse to ensure that any spikes form the ventilation control (if it has any) don't damage the transistor.

     

    I'm picking the output at Pin2 of P12 is 5v, which means that 5 - 0.6 (B to E) = 4.4  I =E/R = 4.4/330 = 0.0133 Amps base current (13mA)  NOTE the GPIO is only 8mA

    At the worst gain of 40 for a 2N2222, that gives you 0.5333 Amps collector current which is all that the 2N2222 is capable of.

    IMO R6 = 330 is the right value, but just check on the ventilation control current required, as you might need a higher gain transistor.

     

    Mark