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Pneumatic solenoid valve help

Jason Barker

May 28, 2018
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hi guys!

i am trying to activate a pnumatic solanoid valve with arduino. i am useing a very basic design that is from this web page https://www.bc-robotics.com/tutorials/controlling-a-solenoid-valve-with-arduino/ i must point out the solanoid is not the one on that page.
i am useing the items it says on that page, though i did order TP120's it appears the things that came are IRLZ34N im not sure if thats the same thing or not.
useing a 7.4 lipo it works correctly at 40PSI however it needs to work at much higher pressures.
at 80 PSI useing a 14.8v battery it semi works. it needs 20 or so activations and each acticvation the valve works better until it works. (again it needs to work much higher)
if the valve is not activated again within a few secconds it will need aditional activations untill it works. i have a video here
plugging the batterys directly in to the soanoid opens it correctly, so it seems as there is something in the design thats preventing power from propperly going to it, or is cutting the power of the battery. can you help?

thanks for your time
 

bertus

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Nov 8, 2019
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Hello,

TIP120 ia a NPN Darlington transistors.
The IRLZ34 is a N-gate mosfet.
The arduino signal should go to the gate of the mosfet, instead of the base of the transistor.
The source of the mosfet should be connected to ground, instead of the emittor of the transistor.
The drain of the mosfet should go to the solinoid, in stard of the collector of the transistor.
There should be a back-EMF diode mounten accross the solinoid.

https://media.digikey.com/pdf/Data Sheets/Vishay Siliconix PDFs/IRLZ34,SiHLZ34.pdf

bertus
 

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Jason Barker

May 28, 2018
17
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Hello,

TIP120 ia a NPN Darlington transistors.
The IRLZ34 is a N-gate mosfet.
The arduino signal should go to the gate of the mosfet, instead of the base of the transistor.
The source of the mosfet should be connected to ground, instead of the emittor of the transistor.
The drain of the mosfet should go to the solinoid, in stard of the collector of the transistor.
There should be a back-EMF diode mounten accross the solinoid.

https://media.digikey.com/pdf/Data Sheets/Vishay Siliconix PDFs/IRLZ34,SiHLZ34.pdf

bertus

I have tried to rearange as you said, but nothing happens now.
https://drive.google.com/file/d/15-k8QcQ4EjI23B__Vkbt-9rd2kE_IvFz/view?usp=drivesdk
 

bertus

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Hello,

Do you still use the resistor on the gate?
If so lower the value to 22 Ohms.

Bertus
 

bertus

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Hello,

Where is the ground connection from the arduino?

Bertus
 

Alec_t

Jul 7, 2015
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Can you post a link to the valve datasheet?

Edit:
I would recommend building your circuit on Veroboard or similar, with soldered connections. Breadboards are not designed to carry heavy current (such as your solenoid may need) and do not provide reliable connections. If the connection to your back-emf diode ever became poor or failed, your Arduino could well be fried by the solenoid's back-emf spike, assuming the Arduino and the solenoid share the same supply as shown.
 
Last edited:

Jason Barker

May 28, 2018
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Can you post a link to the valve datasheet?

Edit:
I would recommend building your circuit on Veroboard or similar, with soldered connections. Breadboards are not designed to carry heavy current (such as your solenoid may need) and do not provide reliable connections. If the connection to your back-emf diode ever became poor or failed, your Arduino could well be fried by the solenoid's back-emf spike, assuming the Arduino and the solenoid share the same supply as shown.

Once I get a working prototype I will have this made in a a proper PCB board
 

bertus

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Hello,

I have drawn the parts again in fritzing, as in the openings post-link:

Arduino_solinoid.png

Bertus
 

Jason Barker

May 28, 2018
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Hello,

I have drawn the parts again in fritzing, as in the openings post-link:

View attachment 47640

Bertus

thats working alot better now thats awesome, i was able to get up to 120 PSI with the 14.8v lipo

if i wanted to increase the stregnth of the solanoid, but keep a lower voltage battery what changes would i need to make do you know?
idealy i would like to be able to get that high on an 11.1v lipo or 7.4v
 

bertus

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Hello,

The use of a mosfet in stead of the transistor already gives more power to the solinoid, as the voltage drop accross the mosfet will be lower as the transistor.

Bertus
 

Jason Barker

May 28, 2018
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Hello,

The use of a mosfet in stead of the transistor already gives more power to the solinoid, as the voltage drop accross the mosfet will be lower as the transistor.

Bertus
i need more, this solanoid was desined to do what im trying to make it with 8.4v ni-h batterys so there must be a way to increse the current even more to match the old electronics. which i cant exactl coppy because its got some sort of coating so i cant see.
https://drive.google.com/open?id=15N1lUnRYUpuRspxl_YjVafpqlN41SnIk
 

bertus

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Hello,

Thicker wire will carry more current.
Measure the supply voltage and the voltage accross the solenoid.
Then you know if there is a large voltage drop accross the wires.

Soldering will also reduce bad contacts as you might have in the breadboard.

Bertus
 

Jason Barker

May 28, 2018
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