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16-channel PWM/Servo Shield for 12V water/air solenoids?
Moderators: adafruit_support_bill, adafruit

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16-channel PWM/Servo Shield for 12V water/air solenoids?

by gjnn on Sat Dec 04, 2021 12:21 pm

Hi,

I am wondering if the 16-channel PWM/Servo Shield can be used to drive 16 water/air solenoids instead of servos. The solenoids I have in mind are these DC 12V ones https://www.ebay.co.uk/itm/252510150316.

Sorry about the noob question, but still quite new to arduinos and electrical engineering.

gjnn
 
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Re: 16-channel PWM/Servo Shield for 12V water/air solenoids?

by adafruit_support_bill on Sat Dec 04, 2021 12:51 pm

Not directly. They need 160mA at 12v. The PWM pins on the shield will only do about 20mA @5v. You would need a transistor on each channel to switch the current - plus a diode to protect against the kickback from the solenoid.

https://learn.adafruit.com/transistors- ... -2998941-9

adafruit_support_bill
 
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Re: 16-channel PWM/Servo Shield for 12V water/air solenoids?

by gjnn on Sat Dec 04, 2021 3:11 pm

Thanks for the help! Do you possibly know if there exists another shield with transistors, that can handle multiple solenoids?

Thanks again!

gjnn
 
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Joined: Sat Dec 04, 2021 12:17 pm

Re: 16-channel PWM/Servo Shield for 12V water/air solenoids?

by adafruit_support_bill on Sat Dec 04, 2021 3:20 pm

You could use a pair of motor shields: https://www.adafruit.com/product/1438
That shield is based on the same PCA9685 chip as the PWM Servo shield - but with the PWM outputs routed to 4 H-Bridge motor drivers.

The output of each H-bridge is basically equivalent to 2 transistor drivers. So you could control two valves per bridge. That gives you 8 solenoids per shield and the shields are stackable.

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Re: 16-channel PWM/Servo Shield for 12V water/air solenoids?

by gjnn on Sun Dec 05, 2021 12:35 pm

Thanks a lot! Might come back later with more specific questions once I've done more reading for the specific project I have in mind!

gjnn
 
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Re: 16-channel PWM/Servo Shield for 12V water/air solenoids?

by gjnn on Tue Dec 07, 2021 9:02 am

Just to be perfectly clear: if I stack 3 shields, I will be able to have access to 8 x 3 = 24 solenoids in total right? I am asking since I was reading this post https://learn.adafruit.com/adafruit-mot ... ng-shields where it says "Note that stacking shields does not increase the servo connections - those are hard-wired to the Arduino digital 9 & 10 pins."

gjnn
 
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Joined: Sat Dec 04, 2021 12:17 pm

Re: 16-channel PWM/Servo Shield for 12V water/air solenoids?

by adafruit_support_bill on Tue Dec 07, 2021 9:14 am

ust to be perfectly clear: if I stack 3 shields, I will be able to have access to 8 x 3 = 24 solenoids in total right?

Correct. You would be connecting your solenoids to the motor channels - not the servo channels.

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