jeinzi

@jeinzi@discuss.tchncs.de

• ⁨Comment⁩ on ⁨Disconnect wire to close a switch with a simple circuit⁩ ⁨⁨1⁩ ⁨week⁩ ago⁩:

  With a PMOS device used for simple on/off switching, placing the load between drain and ground would be correct. With an NMOS FET, the load should be between drain and VCC.

  In general: NMOS source to GND, PMOS source to VCC.

• ⁨Comment⁩ on ⁨Disconnect wire to close a switch with a simple circuit⁩ ⁨⁨1⁩ ⁨week⁩ ago⁩:

  Props for the detailled answer, but this all sounds completely backwards.

  Low-side switching should in general use an N-Channel FET. And with your voltage divider, the gate will be at 6% auf the supply voltage, not 94%, which means the FET will always be conducting. It will also never fully turn on, because that would mean the Gate-Source voltage would drop to near 0, which would turn it off again.

  My counter proposal:

  Image

• ⁨Comment⁩ on ⁨Microcontroller recommendations for a weather station⁩ ⁨⁨3⁩ ⁨weeks⁩ ago⁩:

  I noticed that I glossed over your breadboard requirement. If you want to use something like an ATtiny or CH32, you could always buy some generic SMD breakouts like this. Both of these microcontroller series have internal oscillators and flash memories, so you really don’t need any external components. Maybe a bypass capacitor for good measure.

• ⁨Comment⁩ on ⁨Microcontroller recommendations for a weather station⁩ ⁨⁨3⁩ ⁨weeks⁩ ago⁩:

  If networking is the goal, choose any ESP32 module. If you want something simple akin to an ATtiny, ich can recommend the CH32V003. Is has plenty pins and an I²C peripheral, costs around 15 ct. For accurate timing, add an external oscillator instead of using the internal one.

• ⁨Comment⁩ on ⁨USB PD for older device⁩ ⁨⁨4⁩ ⁨months⁩ ago⁩:

  I’m not sure about the standard - but in my experience, if a PD trigger IC requests 12V, that will be supplied, no matter the current draw. I have used this to power several low power devices, for example a 12V computer fan, and I have also verified this with no load at all. There is also PD PPS, which could be used to deliver 14V or any other voltage.

• ⁨Comment⁩ on ⁨Is SPI just "slow"?⁩ ⁨⁨6⁩ ⁨months⁩ ago⁩:

  I noticed that you use digitalWrite multiple times for each transmitted pixel. That function is pretty slow - you should instead manipulate the microcontrollers registers directly for maximum performance. If you are using an Arduino, this article will help: roboticsbackend.com/arduino-fast-digitalwrite/