12v vacuum and arduino

Hi I purchased this Vacuum: https://www.sparkfun.com/products/10398

I also picked up this mosfet: SparkFun MOSFET Power Control Kit - COM-12959 - SparkFun Electronics

I have an Arduino MEGA and I was wondering if I could power this vacuum using a 12v 4.5Ah battery.

Also if I were to be able to use this battery with the Mosfet to power the vacuum on and off how would I wire it. Thanks.

spiderpro2003:
Hi I purchased this Vacuum: Vacuum Pump - 12V - ROB-10398 - SparkFun Electronics

I also picked up this mosfet: SparkFun MOSFET Power Control Kit - COM-12959 - SparkFun Electronics

I have an Arduino MEGA and I was wondering if I could power this vacuum using a 12v 4.5Ah battery.

Also if I were to be able to use this battery with the Mosfet to power the vacuum on and off how would I wire it. Thanks.

To do what? turn on and off? why not use a switch? I appreciate the links but we also need some background on what your plan of use is and your thought process for the arduino.

It says under Documents that pump is 12W, so at 12V that’s 1A, more at startup if that’s the “running” power. I don’t know how to get the stall or startup current, given the running current, but it’s probably about 5A or so for a short while. (Don’t quote me.)

So you need to check if your battery can provide that current; the Ah you quote is capacity, not the current it can supply.

In principle you would hook it up like this:

SMALL DC MOTOR DRIVER.jpg

Sorry for not specifying. Yes, I simply want the Arduino to be able to turn the vacuum on and off. The reason I am not using a switch is that I have preexisting code that I want to activate the vacuum.

spiderpro2003:
Sorry for not specifying. Yes, I simply want the Arduino to be able to turn the vacuum on and off. The reason I am not using a switch is that I have preexisting code that I want to activate the vacuum.

now it all makes sense. yes the mosfet will run that pump just fine. As far as a wiring diagram its super simple check out the spec sheet and you will be switching the ground. The motor will connect to battery positive. I don't recommend using a 4.5ah battery. If its a sealed lead acid you "should" only drain it down halfway. But that all depends on your uses. let me know how the progress is coming and ill try to help you the best I can.

Wow: a dollar for the actual mosfet and 4x that for the board....

Don’t. Forget. The. Diode.

neiklot:
It says under Documents that pump is 12W, so at 12V that’s 1A, more at startup if that’s the “running” power. I don’t know how to get the stall or startup current, given the running current, but it’s probably about 5A or so for a short while. (Don’t quote me.)

So you need to check if your battery can provide that current; the Ah you quote is capacity, not the current it can supply.

In principle you would hook it up like this:

SMALL DC MOTOR DRIVER.jpg

Um … Didn’t the board already supply a Gate grounding resistor?
Just wondering, I know it won’t do harm to have another.

Also, anyone got any idea what is the gate-source diode doing in RFP30N06LE?

RFP30N06LE datasheet

Cheers

I confess to not opening the mosfet link until after my post with the pic, and didnt realise it was a breakout with pull down, I just saw the word "mosfet". Digrams correct at the component level of course.

neiklot:
I confess to not opening the mosfet link until after my post with the pic, and didnt realise it was a breakout with pull down, I just saw the word "mosfet". Digrams correct at the component level of course.

It's technically correct in any level lol. Nothing wrong with 5k pull down. I'm just saying.

Any idea on what's going on with the MOSFET's GS Diode?

neiklot:
Wow: a dollar for the actual mosfet and 4x that for the board....

What board is that?

TimChPi:
Um ... Didn't the board already supply a Gate grounding resistor?

What board is this? Where is/ was the link to a board?

The gate grounding resistor is to keep the FET switched off when the Arduino is reset and its pins are effectively inputs and may float. Since this problem belongs to the Arduino rather than the FET, the resistor should be across the Arduino pin to ground. If it is on the FET gate, after the series resistor, then it tends to form a voltage divider and reduce the voltage turning on the gate. That may be a minor effect, but it makes sense to avoid even minor impediments to performance.

TimChPi:
Also, anyone got any idea what is the gate-source diode doing in RFP30N06LE?

To protect against ESD (Electrostatic discharge).

Paul__B:
What board is that?

This one:

I also picked up this mosfet: SparkFun MOSFET Power Control Kit - COM-12959 - SparkFun Electronics

That's a breakout board, not just the bare mosfet.

Ah yes, when I looked I saw only the FET sitting there. :roll_eyes:

TimChPi:
Any idea on what's going on with the MOSFET's GS Diode?

The body diode you mean, between drain and source?
That's just there. Part of the MOSFET construction. Can be useful (in e.g. H-bridges and level shifters). Most of the time it's just there, not doing anything, like in case of a simple switch.

wvmarle:
The body diode you mean, between drain and source?

He did say gate-source.

In the datasheet, such a diode - two back-to-back Zeners - is shown.

Paul__B:
He did say gate-source.

True. I assumed it's a typo, which would come as no surprise here.

In the datasheet, such a diode - two back-to-back Zeners - is shown.

Interesting. Gate protection maybe? No word in the data sheet about this.

Definitely gate protection diodes - very useful to have that, first line of defence against gate-oxide failure and
careless handling. Downside is gate leakage currents may be higher than standard MOSFET, affecting gate
driver bootstrapping capacitor choice.

Paul__B:
What board is that?
What board is this? Where is/ was the link to a board?

The gate grounding resistor is to keep the FET switched off when the Arduino is reset and its pins are effectively inputs and may float. Since this problem belongs to the Arduino rather than the FET, the resistor should be across the Arduino pin to ground. If it is on the FET gate, after the series resistor, then it tends to form a voltage divider and reduce the voltage turning on the gate. That may be a minor effect, but it makes sense to avoid even minor impediments to performance.
To protect against ESD (Electrostatic discharge).

How does a back to back Zenor protect against the ESD?

It conducts in either direction when the voltage is higher than the reverse voltage of one and the forward voltage of the other. So a pair of 25V zeners (no o in there) would conduct at about 26V - either direction - limiting VGS to about that level.