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hardware:venta_connected
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hardware:venta_connected [2018/10/14 02:12]
reinhold
hardware:venta_connected [2018/10/28 20:37] (aktuell)
reinhold [section 5]
Zeile 37: Zeile 37:
 ==== 3.1 Power supply: Step-down converter from 24V to 3.3V ==== ==== 3.1 Power supply: Step-down converter from 24V to 3.3V ====
  
-The Venta LW45 humidified ​is powered by an external 24V AC power supply, which should be string ​enough to also power the microcontroller on my board. We simply use the VCC line of the 10-pin IDC ribbon cable and convert the 24V to the required 3.3V of the microcontroller. ​+The Venta LW45 humidifier ​is powered by an external 24V AC power supply, which should be strong ​enough to also power the microcontroller on my board. We simply use the VCC line of the 10-pin IDC ribbon cable and convert the 24V to the required 3.3V of the microcontroller. ​
  
-Initially, I tried a normal LN7805 voltage regulator, but that heated up too much, especially considering that the WiFi-PCB would be placed inside the humidifier ​inside the plastic enclosure with very little air flow. Instead, I'm using a 24V to 3.3V step-down converter to provide the 3.3V VCC to my own board.+Initially, I tried a normal LN7805 voltage regulator, but that heated up too much, especially considering that the WiFi-PCB would be placed inside the humidifier'​s ​plastic enclosure with very little air flow. Instead, I'm using a 24V to 3.3V step-down converter to provide the 3.3V VCC to my own board.
  
 I do not, however, separate my own circuit with optocouplers from the Venta'​s circuit. This means that there is some chance that e.g. a broken comparator on my board might cause 24V to be fed into the microcontroller. That is a risk I'm willing to take, as in this case I'd rather replace the whole board anyway rather than trying to track down which device is fried. I do not, however, separate my own circuit with optocouplers from the Venta'​s circuit. This means that there is some chance that e.g. a broken comparator on my board might cause 24V to be fed into the microcontroller. That is a risk I'm willing to take, as in this case I'd rather replace the whole board anyway rather than trying to track down which device is fried.
hardware/venta_connected.txt · Zuletzt geändert: 2018/10/28 20:37 von reinhold