Controlling multiple fan speed

Hello everyone,

i would like to control the rotation speed of 4-5 fan (12v 0.7a). How can i do this?

Moreover, how can i controls multiple devices (temperature sensors, fan, LCD...).

There's a limit with the Arduino uno I/O pins?

If yes, how can i extend the Arduino I/O capabilities?

Thank you very much

AmigaBlitter:
i would like to control the rotation speed of 4-5 fan (12v 0.7a). How can i do this?

Did you even Google? Lot of hits. But it depends on it you use 2/3-wire fans or 4-wire fans

AmigaBlitter:
Moreover, how can i controls multiple devices (temperature sensors, fan, LCD...).

By connecting them and writing a program that can handle all that. Hint, baby steps :wink:

AmigaBlitter:
There's a limit with the Arduino uno I/O pins?

40mA absolute max, combined all 200mA. Better to stay under 20mA per pin.

AmigaBlitter:
If yes, how can i extend the Arduino I/O capabilities?

Loads of options. Shift registers, IO expanders, just using I2C/SPI devices, connecting it smart (for example multiplexing). Really depends on what you want. But remember, a lot of wires is also a lot of mess I mean problems uhm, work.

Thank you for the reply.

About the four fans: those are a 3 wire fans.

About this “By connecting them and writing a program that can handle all that. Hint, baby steps”, i’ve put the question in a wrong way.

I mean, how many deviced can i connect to the Arduino 1?

Till now i need:

4 fans
5 temperature sensor
1 lcd screen
2 peltier modules.
1 piezoelectric

There are enough pin to control all these devices or should i extend arduino in some ways?

Thank you

3-way fans, use a transistor. I would go for a mosfet.

And about the devices, depends on the details. For example, each fan independent? What temperature sensors? If you take a 1-wire or I2C sensor you just need one set of pin(s). Lcd the same, what lcd? And for the peltiers (and depending on the type, for the piezo s well) use a transistor again.

“Worst” case:
4 pins for fans
5 pins for temperature
6 pins for LCD
2 pins for peltier
1 pin for piezo

18 pins ← would just fit on an Uno even keeping the Serial pins free.

“Best” case:
4 pins for fans
1 pin for temperature (1-wire)
2 pins for LCD (I2C)
2 pins for pertier
1 pin for piezo

10 pins ← More then enough pins on a Uno