Boost 5V (4.7v) to 9V

Thanks for your answers!

The motors don't run from the 5V connection from the Arduino ;-)

But no capacitor is there for the motors. I'll try to add them.

Btw, the motors sort of run at 5V, but I might still be buying the step up module soon!

Thanks!

Tim

Tim

You haven't specified how you are intending to control the motors.

Are you using a H Bridge, or just connecting them so they operate in one direction only.?

A little more detail and we can provide a couple more suggestions.

As john said connecting a motor to the 500mA 5v regulator on an Arduino is not a good idea.

Even when its across the Vin terminal, it usually causes issues.

Mark

Sorry,

I'm using a custom build H-bridge, powered directly from the powerbank.

EDIT:

Is a 10uF capacitor rated at 50V big enough for the whole? and two 0,1 uF capacitors rated at 50V for the motors?

Hi Tim,

Could you share more detail on the custom H-bridge (e.g. schematic) and the motors (datasheet, or voltage and power requirements).

Phoefff, that's a damn good question

The input voltage is (as I assume 9V)

That's all I know

Phoefff, that's a damn good question

The input voltage is (as I assume 9V)

That's all I know

The ULN2803 can't easily be used for bidirectional motor control without additional complexity. It can't reverse the current to the motor on its own. There are better alternative ICs, and probably some pre-built boards that are low cost. But it all depends on the motors. Are these small hobby/toy motors (in which case we can guess current consumption)? Otherwise some more information is needed on the motors unfortunately.

The motors are these yellow ones (this is not the exact robot I'm using)

http://www.makershed.com/products/makeit-robotics-start-kit

Maybe this is going to help you. To be very honest, I know exactly as much about the motors I'm using as you do. I've borrowed the robot skeleton from someone.

Hi Tim,

That helps, looks like it probably doesn't need more than a couple of amps at maybe around 4.5-5V to run those. 9V is probably too high for the motors, maybe? Could you test by directly connecting the motor to a 4.5V battery (e.g. 3 AA alkaline batteries) or a 5V DC supply, and see if it is adequate?

For the H-bridge circuit, check out something like L293D (the D suffix version is important, otherwise you need additional diodes), e.g. see here: https://learn.adafruit.com/adafruit-arduino-lesson-15-dc-motor-reversing/overview