So I am working on my first Arduino project and I am having a bit of an issue getting the solenoid to push and then pull. I followed this tutorial: Controlling a Solenoid with an Arduino - Tutorial Australia (core-electronics.com.au)
to the best of my knowledge but does not have the solenoid act the way it is suppose to. For e the Solenoid retracts (and then stays retracted).
Looks like you have the transistor wired wrong, which transistor?
Also, from the Amazon page:
Question:
how many amps does it need?
Answer:
The coil windings run about 7.3 ohms, so at the stated 4.5v operating voltage they would draw 616mA or 0.616 amps.
By Russell Gray on September 27, 2019
That's way too much current to be drawing from the Arduino AND your laptop, you need a separate 5V, 2 Amp power supply for that solenoid.
I have an NPN Transistor. It came with the starter Arduino kit. If it helps, I do have a kit of power transistors. Which one would be optimal? Currently i replaced the NPN Transistor in the circuit with TIP125 and I get the same result.
So I hooked up my power supply to see if it resolved the issue. It did not sadly. I did some research and I did have my transistor rotated the wrong way. Oddly enough that didn’t change my outcome.
The link you gave is lying. Very common on the internet! Look at the return spring. That ensures the solenoid ONLY OPERATES ONE WAY!!! The look at the back side. Notice there is no part of the armature that extends through the frame. Also a clue that the solenoid is ONE-WAY.
I bought 4 solenoids on Ebay that were listed as push-pull. The pictures showed they could have been. But when I got them I discovered there was an INTERNAL return spring. I was able to modify them to do what I wanted.
So, there are the clues to look for, not the sellers description.
Good luck!
Paul
TIP125 is a PNP, use the TIP120 (NPN), connect 5V+ from external supply to solenoid + and diode cathode (end with band), solenoid - and diode anode to TIP120 collector, TIP120 emitter to 5V GND. TIP120 base to 1K resistor, other end of resistor to Arduino output pin, Arduino GND to 5V supply GND.
I tried that transistor with the associated resistor and it did not work. I think the solenoid i have is incorrect then. I read online in the amazon link more carefully and it states it only allows for one way motion (Which is misleading). Is there any way for me to connect my controller to the solenoid that I have to receive the 5V+ power, and when I do, signal the controller to delay and then discharge it to ground in the configuration I have? Is there a configuration that is possible with my current solenoid?
I really dont want to have to repurchase a new solenoid. If i have to, please direct me to a recommended one.
I have connected the solenoid to a 5 Volt DC power supply and it did retract. What i would like for the solenoid to do is to retract, what 1 second and then unretract via the controller. Would removing the spring help? I havent done so yet. A bit worried i may tear it apart
sirvonny:
I have connected the solenoid to a 5 Volt DC power supply and it did retract. What i would like for the solenoid to do is to retract, what 1 second and then unretract via the controller. Would removing the spring help? I havent done so yet. A bit worried i may tear it apart
Then you will have to have a controller that REVERSES the polarity of the current. Removing the keeper and spring will do that. BUT!!!!! that will allow the armature to shoot away out of the solenoid core. DO you have such a controller and is that really what you want to happen?
Paul
Your transistors are darlington type, which means you'll loose minimum 2V across the transistor, leaving only 3V for the solenoid. Note that they used a 2N3904 in the tutorial which is too small (only 200mA) ... a PN2222A would be a better choice as it can switch 1A. Otherwise, you could get this working with your existing parts if you use a 7.5V DC supply.
A push pull solenoid just means it has a push-rod at one end and a pull-rod at the other...
Its a solenoid, activating moves it one direction, deactivating and the spring pulls it back the other.
MarkT:
A push pull solenoid just means it has a push-rod at one end and a pull-rod at the other...
Its a solenoid, activating moves it one direction, deactivating and the spring pulls it back the other.
I disagree. I recently had a solenoid project and looked at my box of solenoids. There were quite a bunch with NO springs or keepers. The armature had been pinned to something and that could have had a spring, but the solenoid could also have been used to alternately push and pull the connecting mechanism.
Paul
Looking at this particular solenoid, its got a pull-rod extension and (although the second photo is
tiny), a hole the otherside for a push-rod. It looks to be a standard solenoid, nothing fancy other
than the pull-rod extension.
