Choosing the correct electronic switch for my project of a PIR Sensor turning on an Air Valve

Hi !

You can use a relay to open the valve. You don't connect the valve to the arduino, only the relay. The power source connects to the relay and when the arduino sends a signal, the relay opens and let power to the valve. Another signal from the arduino, the relay closes and the valve turns off.

There are a lots of tutorials out there on how to connect a relay to an arduino. It's really easy.

The relays, there's also a lot out there.

https://pt.farnell.com/search?st=arduino%20relay&gs=true

Thanks for your reply.

The reason why I don't want to use a relay is because I'm trying to reduce the size of the electronics to a minimum. Space is at a premium in this project

Thanks anyway.

For proper advice, the air valve electrical datasheet is required. 

It is likely a solenoid with inrush current as well as holding current, and required supply voltage would be a good thing to know. The solenoid coil will need a flyback diode, RC suppressor, or MOV to eliminate switching transients to avoid destroying the semiconductor driver.     

Please advise  

Hello,

It's a solenoid air valve on Aliexpress. The details about it as per usual on Aliexpress are not extensive.

https://www.aliexpress.com/item/1005003358370091.html?spm=a2g0o.order_list.order_list_main.27.774a18025SktNw

Type: (normally closed) solenoid valve

Voltage: DC 6.0V    Current: <330mA

Fluid medium: gas (non-corrosive gas, mainly air)
Gas flow: typical 5-6L/MIN, 2LPM/MIN-9L/MIN optional
Vacuum negative pressure: ≥-60KPA (-450mmHg>
Forward pressure: >100KPA(750mmHg)
Noise: <55dB (typical value)
Life:>50000 times (pump 300mL container, work for 10s, stop for 5s)
Pipe diameter: Φ 5 mm
Weight: 15 g

I bought the 6.0V model. I'll check all your suggestions. Apart from the flyback diode I'm not familiar with any of them.

Thanks for your help

What is the timing requirement for the valve?

I have used PIR sensors to turn on motors for a period of time without needing any MCU. I just used a PIR module and a large FET. The sensitivity and duration were both adjustable with little pots on the PIR module.

This video gives some idea of the size of the circuits:

 The Creature from the Crab Nebula 

IRF520 MOSFET will more than do the job. Yes, a smaller transistor could do the job, but why bother ? 

When the project is done, these MOSFETS can be reused with DC motors ( if they only run one direction ) , solenoid drivers, and banks of LEDs.  https://www.vishay.com/docs/91298/irl520.pdf

I'd use qty 4 AA batteries ( qty 5 AA if you use rechargable batteries) to provide the power to the solenoid coil and also to the Arduino power jack (not the 5V supply) .  Put a 100 or 200 ohm resistor in the MOSFET gate driven by the Arduino output.  

make sure to put a flyback diode around the coil's terminals

Its not clear if the solenoid can operate the the 500ms pickup and drop out time, the driving pulse may be longer to allow for pickup.  

https://www.newark.com/infineon/irf520npbf/n-channel-mosfet-100v-9-7a-to/dp/26AC0588?st=IRF520

https://www.aliexpress.us/item/3256805944681939.html?spm=a2g0o.productlist.main.1.5a904612sYK4JW&algo_pvid=b7aa577b-f5f8-400b-aafc-c3f9423ee352&algo_exp_id=b7aa577b-f5f8-400b-aafc-c3f9423ee352-0&pdp_npi=4%40dis%21USD%216.52%210.99%21%21%2146.75%217.07%21%402103011617084498862327174e8cb8%2112000035899336544%21sea%21US%210%21AB&curPageLogUid=Ve6MWM47Grpj&utparam-url=scene%3Asearch%7Cquery_from%3A

https://www.aliexpress.us/item/3256806230838343.html?spm=a2g0o.productlist.main.25.5a904612sYK4JW&algo_pvid=b7aa577b-f5f8-400b-aafc-c3f9423ee352&algo_exp_id=b7aa577b-f5f8-400b-aafc-c3f9423ee352-12&pdp_npi=4%40dis%21USD%212.06%210.68%21%21%2114.77%214.85%21%402103011617084498862327174e8cb8%2112000037089810922%21sea%21US%210%21AB&curPageLogUid=VY612DDoeioE&utparam-url=scene%3Asearch%7Cquery_from%3A

Just add that although the IRF520 may work for the Arduino UNO, it is safer to work with the IRL520.

IRL520 and IRF520 are different MOSFET. The L of the IRL520 shows that is a logic level MOSFET.

A logic level MOSFET is designed to turn on fully from the logic level of a microprocessor. The IRF series is designed to run from 10V.

Thanks. Good point. Altho I havent had issues using IRF520s or the other hodgepodge assortment of N type MOSFETS in my box of magic, doesnt mean the next person wont.  

Whats funny is the datasheet link I posted is the IRL520  ;-)  

 rictrajano you have two choices the Relay or the MOSFET. Now you must choose! ~~ Cris 

Thanks so much for the extensive and detailed reply. I'll start now checking my options.

In relation to the battery I'm thinking on using 2x 14500 Li Ion batteries with a charging module

https://www.aliexpress.com/item/1005005554822742.html?spm=a2g0o.order_list.order_list_main.11.575c1802jlpcCr

https://www.aliexpress.com/item/1005005563182809.html?spm=a2g0o.order_list.order_list_main.5.575c1802jlpcCr

Do you think this will do the job?

Thank you again