I have a solenoid valve purchased from adafruit with a TIP120 Power Darlington Transistors and a 1N4001 Diode hooked up in this manner as this picture shows in the link, tr | purovargas819 | Flickr. I check with the multimeter the voltage coming out of the switch when the arduino sends the output to turn on the switch and it reads 9 volts but when I hook up the solenoid valve to the transistor and turn the arduino on to give the signal nothing happens and the with the multi meter hooked up to the solenoid I read zero volts but right when I unhook the solenoid valve the voltage spikes right back up to 9 volts. Can someone please help me in figuring out this problem, I will appreciate it greatly. Oh and with a small 9 volt battery I tested the solenoid valve to see if it's working and I get a response always from the solenoid. But the funny thing is that this solenoid is supposed to be closed when voltage is not applied and I hook the water up and the water will flow through and when the battery is applied the valve will shut and this is not what adafruits site says how the valve is supposed to work.
R(base) ?
V(base) ?
I (collector) ? (collector current )
You would be better off using a logic level MOSFET
RFP30N06LE.pdf (189 KB)
I use a 2.2k resistor connected from the arduino to the base, 12v supply and I had a 1uF capacitor hooked up to the solenoid valve ground and power to the collector and ground to the emitter. It works without the solenoid valve hooked up but when it's on that's when it messes up. I ordered a mechanical relay from sainsmart to see if that would help in switching the valves on and off but I hate it that these solenoid valves need constant power to remain closed valves and their site says the opposite for them.
V(base) ?
I (collector) ? (collector current )
4.4 volts goes into the resistor into the base but I don't know the current sorry I just have 12v and sometimes 9v going into the collector.
So you are saying you don't know how to put the black lead of the multimeter on ground and the red lead on the base of the transistor ? And you don't know how to move the red lead of the meter to the 10A current jack of the meter and select dc current on the multimeter and then put the two leads IN SERIES with the collector of the transistor ?
I don't have it hooked up right now, I am writing everything based on memory from this morning. If I had it all hooked up right now I would have told you.
purovargas819:
I have a solenoid valve purchased from adafruit
Which one? They sell two different ones.
There you go being technical again....
It's the plastic solenoid valve
Remember this ?
V(base) ?
I (collector) ? (collector current )
Since you're way too busy to be bothered with uploading the datasheet for the transistor I'll do that for you.
Unfortunately I can't read a crystal ball to see what your base voltage and current are...
TIP120.pdf (535 KB)
When I get it hooked back up later on I will post those
purovargas819:
But the funny thing is that this solenoid is supposed to be closed when voltage is not applied and I hook the water up and the water will flow through and when the battery is applied the valve will shut and this is not what adafruits site says how the valve is supposed to work.
Have you definitely got the water flowing the right way? These devices use
pressure-feedback to switch and are only designed for flow one way with a minimum
pressure needed to guarantee correct functioning - without this they will leak.
When I had it hooked up to the hose with the water flowing in the direction the arrow points to it did not want to react when I tested it with a 9v battery but when hooked with the water flowing opposite the arrow points to the water flowed through and when connected with the 9v battery the solenoid closed and open when disconnected.
Here is what Adafruit says about the plastic solenoid valve:
When 12VDC is applied to the two terminals, the valve opens and water can push through. The valve has a gasket arrangement inside, so there is a minimum pressure requirement of 0.02 Mpa (3 PSI). Also, liquid can only flow one direction.
Forget the Arduino and the transistor for the time being, and get the valve working according to this description.
Do you have the minimum required water pressure?
If you use a 9V battery for testing, it MUST BE FRESH as the valve draws 240 mA @ 9V. The battery won't last long, either.
I have it hooked up to the water hose from my house and it says on the site that the valve will work down to 6 volts and it will work the opposite of what they say when connected with the water going opposite of what the arrows points towards. It will turn on and off with the battery but with voltage applied it will be closed and I wanted it to be the opposite of that and yes the battery dies fast.
Contact Adafruit technical support.
I have it hooked up to the water hose from my house and it says on the site that the valve will work down to 6 volts and it will work the opposite of what they say when connected with the water going opposite of what the arrows points towards.
If you are going to make a statement like that on a forum post you need to post the link where you got that information.
It will turn on and off with the battery but with voltage applied it will be closed and I wanted it to be the opposite of that
Plastic Water Solenoid Valve - 12V - 1/2 Nominal : ID 997 : $6.95 : Adafruit Industries, Unique & fun DIY electronics and kits It says here 6 volts minimum and I did contact them and they said to send them all back since they all work that way and they will replace them but it took a while just to get them and I wanted to see if I can make them work.
Ok. First of all, how did you plan to turn on and off this solenoid ? (from an arduino ?)
Second: if you want to invert the logic (you know what that means , right ?) you just need to turn the solenoid on with a transistor. If you don't know how to do that
let us know.