Question about a relay (beginner)

Hello everyone,

im currently planning my first project and wanted to include a pump. The set i bought with the pump contained a relay aswell and many people seem to use it in similar projects to mine.

I personally use an arduino uno and i believe i dont need to include a relay, right?

My assumption is that i connect the pump to an analog output port on the arduino so i can regulate the power of the pump as well as the duration (as i can turn the port on/off at any time). A relay wouldnt help me at all right? am i correct that a relay is only useful, if my output port has insufficient power/wrong voltage to power the pump? or will my idea without a relay affect the longevity of the pump/arduino in any way?

thanks in advance!

  1. A Uno does not have analog output ports. Which pins are you thinking they are?
  2. All output pins almost certainly have insufficient power to run a pump directly even though you have given no details of your pump.

If you want to control the speed of the pump you will need something like a MOSFET circuit connected to a PWM pin and, unless the pump is really tiny, a separate power supply for it. For more details you'll need to provide some information about the pump (a link to a datasheet would be ideal).

Steve

slipstick: 1. A Uno does not have analog output ports. Which pins are you thinking they are? 2. All output pins almost certainly have insufficient power to run a pump directly even though you have given no details of your pump.

If you want to control the speed of the pump you will need something like a MOSFET circuit connected to a PWM pin and, unless the pump is really tiny, a separate power supply for it. For more details you'll need to provide some information about the pump (a link to a datasheet would be ideal).

Steve

Hey Steve, thanks for the quick reply!

oh, good thing i asked. I thought those ports with a squiggly line(~) in front of them were analog outputs, so i could define what voltage i wanna use (ports 3,5,6,9,10,11)

about the pump, i havent found a data sheet but its this one

its listed for 3-5v DC.

Hi, Your pump.

SPECIFICATIONS Product model: JT-DC3W/3L Rated voltage: DC3V/4.5V Product power: 0.36W Maximum flow: 100L/H Head: 0.35m/4.5V 0.5m [u]Current: 0.18A[/u] Noise: 040db MAX Water temperature: -20 ~ 50 ° C Ambient humidity: 45%-90% Motor: Brushed DC motor Size: 42.6*23.9*22.71mm

180mA cannot be supplied by an Arduino output, plus you need to supply the motor with 3V, not 5V from the UNO.

Tom... :)

That's the run current, the stall current will be much more, perhaps 1A.

(deleted)

Hi, This may help about analogWrite and PWM. Arduino PWM Tutorial

Tom.. :)