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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'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