Power control for external modules.

Projects General Guidance
1

Hi,

I'm using an HC-05 bluetooth module in my project. To be able to configure the module properly it is necessary to turn it off and on again in certain conditions. I want this to be controlled by Arduino so the question is, what's the easiest way to implement the necessary hardware? From what I've gathered the module can draw up to 40 mA @ 3.3V. To be safe I'd like to be able to handle maybe twice that... Size does matter though in this case so the smaller the solution, the better.

Thanks,
Kari

2

Logic level, low Rds, P-channel MOSFET as high side switch.

3

Thanks for the food for thought CrossRoads! That particular MOSFET is probably too big but now that I have the idea I can search for a more suitable one. I threw together a quick schematic (see attachment). Is this the way you use them?

Edit: removed erroneous schematic.

4

MOSFET is "upside down"

5

CrossRoads:
MOSFET is "upside down"
AB-001: Discrete Driver Circuits For Vibration Motors - Precision Microdrives

Oops... Shouldn't draw schematics after midnight :stuck_out_tongue: Attached is a corrected schematic plus a pull-up resistor as suggested by the article above.

p-mos.png

6

There you go.