I have created a 6 station UNO water system, but, I have little idea how to set up my power.
I have a 24vAC power pack that drives my water solenoids and I would like to be able to convert that down to 9vDC for the UNO so that there is only the one power pack for the solenoids and the UNO.
Can someone point me to a gadget on ebay that would be appropriate. I can solder but am pretty useless at understanding electronics.
Always show us a good schematic of your proposed circuit.
Give links to components.
Do not use your Arduino 5v pin to power the relay board.
Your I2C connections appears to be wrong.
Can't very well show proposed components when I have no idea what components to use.
Well, the I2C works, there is a break under the resistors, the keyboard lcd and RTC all use the I2C.
Not interested in 5v, the water solenoids ( which arn't shown) use a 24vAC power block, so I just need to get 9v DC from that 24V AC.
That makes more sense.
If you power the Arduino from 9v on Vin and power the relays from the Arduino 5V pin, there is a very good chance you will damage the Arduino voltage regulator.
Suggest you use an external 5V power supply to power the 5v devices; do not power the Arduino from the external power supply when it is connected to the PC via USB.
Something similar to this:
Currently driving the relays on the desk using the 5v from the UNO, but, I accept that it might be an issue.
So what I need now is a way to get both 5v DC and 9v DC from my 24vAC power pack.
Seems silly to me to use a 9v power for the UNO 5v for the relays and 24v for the solenoid.
My water controller is to replace a dying commercial controller that has as its power input a single 24vAC power pack.
No, you do not need 9V if you use a 5v external power supply.
Just 5v... and power the Arduino via the 5v pin rather than the Vin jack input.
OK then I need to convert my 24vac down to 5vDC to supply the ARDUINO and the relays that will switch the 24vAC for the solenoids.
Do not recommend using the 24VAC to generate 5V as there will be no isolation between the Arduino circuitry and the solenoids.
BTW
We do not see any power supply decoupling on the solderless breadboard.
de-whatling???
http://www.thebox.myzen.co.uk/Tutorial/De-coupling.html
A 100nF ceramic capacitor on the power pin of each PCF8575 is needed.
Thank you, don't recall seeing 100nF ceramic capacitor anywhere before but live and learn or melt something.
The lack of capacitors may explain some of the occasionally screwiness that my current program has.
Here's what I had and what I think I need.
I understand that would work, but, I would have to have two power packs running all the time. Surely there is a gadget that can turn my 24v AC into 5v DC.
I have a regulated voltage kit from that will convert 15-18v DC to 3v-15v DC and I am hoping there is a similar something for my needs.
Looking in ebay there are these thingies LM259 AC to DC 3.3v 5v 9v 12v 24v Step Down Converter Module Rectifier ZK
I am hoping that someone will say "yep get one of those thingies" OR " NO get one of these thingies"
I see above you said "Do not recommend using the 24VAC to generate 5V as there will be no isolation between the Arduino circuitry and the solenoids." I don't understand why it would be an issue, All sorts of things have to have multiple voltage values and they are sourced from a single supply????
Also, does there need to be some capacitors on the 5v circuit going to the uno and the relays to deal with de-coupling???
thank you
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