Hi all, not very big on electronics i'm afraid... I made a project running 2 solenoid valves on/off on my arduino. I made a sketch to illustrate what i've got so far. What i've got so far is 2 solenoid valves that require 24V according to the specs connected on a relay to the arduino and on a external power supply of 12V. I didn't have a spare 24V laying around so i thought i tried it with the 12V and that worked. That's question nr 1, can that do harm to my valves since the specs say 24V? They work ok on 12V, they open and close perfect. Further i have powered the arduino uno to an external power supply of 9V. That makes that my project runs on 2 different power supply's. Question nr 2 is can i power the arduino on the same power supply as the valves or is there any other way i can get 12V or 24V to the valves and still power the arduino without the need to add a seperate power supply? Thx for the advice !
If you want to power the valves with 24V then you will need another component as you cannot feed 24V into the Arduino.
A couple of options.
- Two power supplies stacked, 9V and 15V. GND to 9V for the Arduino and GND to 24V (9+15V) for the valves. Workable but not pretty
- Two power supplies independent, 9V and 24V. More common values of power suppplies, but not what you want.
- One power supply with DC-DC converter or buck converter. 24V power supply connected to the valves and split to be connected to the Arduino via a step-down buck converter or a DC-DC converter (to change 24V into 5V). works and all parts available, really not much different than #2
- Buy 12V valves and use 12V to power the new valves and the Arduino. An option if the valves are available.
Your valves will not necessarily function properly at 1/2 voltage.
Arduino are best run at 7 to 9 volts but 12v will do if not too much current is taken from the 5v pin.
Kick back diodes across the values are needed. 1N4007.
pengocha:
Hi all, not very big on electronics i'm afraid... I made a project running 2 solenoid valves on/off on my arduino. I made a sketch to illustrate what i've got so far. What i've got so far is 2 solenoid valves that require 24V according to the specs connected on a relay to the arduino and on a external power supply of 12V. I didn't have a spare 24V laying around so i thought i tried it with the 12V and that worked. That's question nr 1, can that do harm to my valves since the specs say 24V? They work ok on 12V, they open and close perfect. Further i have powered the arduino uno to an external power supply of 9V. That makes that my project runs on 2 different power supply's. Question nr 2 is can i power the arduino on the same power supply as the valves or is there any other way i can get 12V or 24V to the valves and still power the arduino without the need to add a seperate power supply? Thx for the advice !
Hi,
That's question nr 1, can that do harm to my valves since the specs say 24V?
No
They work ok on 12V, they open and close perfect
Try them with the water (or whatever fluid) passing through or exerting pressure.
is there any other way i can get 12V or 24V to the valves and still power the arduino without the need to add a seperate power supply
Yes, but the right way is -specially when using solenoids- to have separate power supplies. There are many other "best practices" (freewheel diodes; separate circuits, ...).
Regards.
larryd:
Kick back diodes across the values are needed. 1N4007.
Added diodes, think they're correctly placed? (updated attachment)
The first thing that would concern me, is whether these solenoid valves are specified for DC and not AC.
1N4007 are 1kV diodes!, completely unnecessary for 24V use, 1N4001's are fine, but any 1N400X diode
is fine for this - kickback diodes only have to deal with the supply voltage and the operating current of
the solenoid - and the type isn't even critical as its switch-on that matters. They prevent high voltages,
they don't have to handle high voltages.
Cheap eBay buck converters based on the LM2596 are my go-to simple/cheap buck converter for this
kind of use, good for an amp or two, output voltage adjustable with a 10 turn pot, some come with a
voltage display even. Only caveat is they will be too noisy for low level analog signals and electronics.
"1N4007 are 1kV diodes!, completely unnecessary for 24V use, 1N4001's are fine, but any 1N400X diode
is fine for this -"
The price is exactly the same, if you got em, smoke them.
The manufacturing process of the 1N4001-4004 seem to be different from the 1N4005-4007.
Making the first group slightly 'better' for low voltage.
Look at the datasheet(s). Some specs are split into those two groups.
Leo..
Which datasheet(s) are you looking at? None of the five datasheets I looked at made such a distinction.
Can't find the article I found it in anymore.
Was partly about turn-on time between a 4004, 4007 and schottky diode if I remember correctly.
Some datasheets give a typical junction capacitance of 15pF for the first group and 8pF for the second group.
Leo..
Edit:
Might have been this document.