How to connect the fan to nRF52840

[Jerry Zheng0521]

Hello everyone.

I am going to do a project recently. We are using dht22 to transmit temperature and humidity, and use temperature values ​​to control LEDs.

This project has been completed, but we plan to change the LEDs into fans.

What should I do?

As shown in the picture, How do I connect this fan to the nrf52840?

Thank you!

[JONATHAN LL]

Hi,

The nRF52840 does not support driving as 5V fan from any of its GPIO's so you would need to use some external circuitry. You could use a fan controller that talks to the nRF52 or use something like electronically controlled switching circuit to turn power on or off to the fan.  This can be done with a som FET and basic components. 

Regards,
Jonathan

[Jerry Zheng0521]

Thank you for your answer!

Can I use model 9013 BJT as a switch?

Is it feasible to drive the fan by connecting the positive pole of the fan to the 5V of nrf52840, the negative pole to C of the BJT, and B to the GPIO output?

Thank you!

[JONATHAN LL]

Hi,

I have not read the datasheet of the Fan that you are using, but it could be doable, not sure how much current it will draw and if the nRF52840DK is able to supply that from the 5V rail. I guess it will work since it is listed as R-pi fan. But in theory i can be done. 

You will have to test this yourself. Maybe try with a LED and a series resistor first so that you dont burn up the LED. 

Regards,
Jonathan

[Jerry Zheng0521]

Thanks for your answer!

I'm currently encountering another problem

I want to develop this project in visual studio code.

If I want to add a fan. I seem to need to add a node to the device tree, but after I add it, there is a field for "compatible".

I don't know what to fill in.

Do you have any idea?

[JONATHAN LL]

Hi,
Can you create a new ticket for this issue? Would help keep the topics of the DevZone tickets more organized. 

Thanks