I've created the following model for a school project. This is the first time I'm attempting to read sensors or write alarms etc. using a microcontroller.


How I can improve it? To me it seems likely that there's a way to combine these voltage converters.

As I was thinking, I could perhaps use one pin to control/read the sensor and another pin to 'multiplex' the other pin to the correct sensor after it's voltage has been shifted from 5V to 12V.

Would you recommend this approach? Or is there a much better or more common alternative?

Note: All sensors have to be read, whereas the alarm has to be set. The temperature sensor is an analog sensor, all other sensors are digital.

  • \$\begingroup\$ Just use 5V sensors. It seems to me that 5V powered devices are all available for the types of applications in your diagram. \$\endgroup\$
    – Andy aka
    Oct 29, 2015 at 14:35
  • \$\begingroup\$ Are you talking about voltage (power) converters or only signal level converters? What kind of signal do the sensors give? Logic or analog? \$\endgroup\$
    – Botnic
    Oct 29, 2015 at 14:37
  • \$\begingroup\$ @Andyaka My teacher will only provide us with 12V sensors to force us to do some voltage shifting. \$\endgroup\$ Oct 29, 2015 at 14:39
  • \$\begingroup\$ @Botnic I think I explained this at Note:, only the temperature sensor uses analog, all the other sensors are logical. \$\endgroup\$ Oct 29, 2015 at 14:40
  • \$\begingroup\$ @user1534664 right sorry. Then I would do it like you showed. 12 to 5V conversion is easy, small and cheap. Easier than every shifting or multiplexing. Only the Alarm has to be done separately. \$\endgroup\$
    – Botnic
    Oct 29, 2015 at 14:46

1 Answer 1


Why not use something like a ULN2003A or another variant of that family? They are used extensively as interfaces between low level and high level devices.


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