Cheap Sprinkly Pi

[korban]

Hi,

I was looking at a cheaper way of making an OpenSprinker Pi and was wondering if you really needed the RTC?

Could it just update from the network/web?

Also with the 5v power supply, I’m running mains to the unit anyway for the 24VAC transformer, could a just use a cheap mains to 5V 1A USB charger?

eg http://dx.com/p/uk-plug-usb-power-adapter-blue-white-100-240v-1a-171062

[Ray]

If you don’t need 24VAC->5VDC conversion, and you don’t need RTC, then you can get the OpenSprinkler Zone Expansion Board, which requires a minimum of 6 pins (3.3V, GND, and four shift register pins) to interface with Pi.

[korban]

Would there be any issue tying the ground of a 240 to 5V converter to once side of the 24VAC? I assume they would need to be joined for the triacs to operate?

And does your code operate fine without the RTC?

[Ray]

Yes, one wire from 24VAC transformer is the COM (common) wire, and the other wire should be tied to ground. AC transformer is no-polar, so it doesn’t matter which wire you pick as ground.

The code does not use RTC at all.

[Author]

Posts