help with solenoids

Hi,
I have to use solenoids with Arduino. I've checked the Solenoid Tutorial on Arduino Playground, but honestly I'm really new to electronics etc and there's a lot of things I don't understand about the schematics...

Are the IRF640 transistor and the zener diode D2 a unique component, or do I have to link them together?
What is JP2? And TP1 and TP2?

I tried to understand something more from the pictures, but they're really messy and don't help at all...

I hope you guys can help me!
Thank you very much :slight_smile:

Elly

Here's the link to the schematics I was checking:
http://www.arduino.cc/playground/Learning/SolenoidTutorial

The forum didn't let me post URLs because it was my first message XD

JP2: a two-contact jumper, a plug. "Your input comes in here."

TP1, TP2: test points, convenient places in the circuit where you might probe with your multimeter or oscilloscope during testing

D1: separate part, should be used to protect rest of circuit from spike which happens when solenoid coil goes unpowered

D2: contained within the IRF-branded part, could be added to protect other types of FETs in similar fashion

There is a simpler diagram here: Arduino Playground - HomePage

Its for a relay but a solenoid is pretty much the same thing (a typical relay is a switch controlled by a solenoid)

Also, there is tutorial here that goes into more detail:
http://www.instructables.com/id/Connecting_a_12V_Relay_to_Arduino/

thanks so much for the fast answer :slight_smile:

now I understand a bit more.. however I'm not 100% sure how to build this thing yet..

In this other link I found the thing looks a bit easier to build..

I have a "6Vdc cont. push solenoid" that needs to play a bell.

Could the 'SOLENOID power V+' be connected to the Arduino 5V Pin? would that be enough? or shall I connect it to an external 6V power supply?

Could the ground of the solenoid (passing through the transistor Q1 TIP102) go straight to the Arduino GRD without damaging anything?

thanks a lot :wink:

The solenoid ground can and should be connected to the Arduino ground. Powering the solenoid depends on its particular requirements. If it's a big beefy thing then you will probably need external power but the Arduino +5 volt line may be ok for a small solenoid.

btw, the picture in your link is more or less the same as the one reply#3.

Thank you SO MUCH :slight_smile:

Err... just another thing :stuck_out_tongue:
Can I replace the TIP102 with a TIP120? I just have it here and wanted to know if that's ok too without buying a new one...

I just checked the datasheets for the transistors and you should be OK. Do you have a datasheet for the solenoid?

This is my solenoid:

The TIP 120 will be more than adequate. But you will need to use an external power supply, 6 volts DC at least 1 amp (although a 5 volt 1 amp supply should work in a pinch)

What are you making?

Does the external power supply depend on the transistor or on the solenoid model?

It depends on the solenoid. Yours wants 6 volts at a little over an amp.

There are lots of devices that use a 5 or 5.5 volt 1.5 amp wall warts that you may be able to scrounge. I seem to have a box full of them from old IP routers and switches that were junked

Ok, thank you very much!