Water Tank Level/Water bore controller

Thread Starter

buck1106

Joined Jul 31, 2015
5
Hey guys,
I have purchased a Raspberry Pi 2, Open Sprinkler plus, sd card, wifi adapter, 1kohm resistors and an ultrasonic detector.
I am going to setup my heavy water using irrigation system to the raspberry pi 2 and open sprinkler plus attachment. I was wondering how I could go about using this ultrasonic detector to determine the level of the water tank and control the water bore so it is on when the water level is low but off when it is high. I want to be able to check the level of the tank without having to physically extract the 'dip stick'.
I want to be able to keep it at a maximum of 85% in order to allow for any rainfall to not be wasted. It should be noted that it generally lies around 50% but declines over summer. The water bore is 100m away from the tank. I was thinking of connecting an normally closed solenoid (as normally open are too expensive) at the input of the tank and hooking it up with a solid state relay connected to the raspberry pi and the associated resistors to control voltage.

I am a novice at this sort of project but i'm a quick learner and would love any input with regards to ideas or code.
Any ideas would be greatly appreciated.

Many Thanks,
 

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bertus

Joined Apr 5, 2008
20,675
Hello,

Most solid state relays I know have an infrared led as input.
I do not see a current limiting resistor for the led in your schematic.
Do you have the specifications of the solid state relays?

Bertus
 

ebeowulf17

Joined Aug 12, 2014
3,274
Hello,

Most solid state relays I know have an infrared led as input.
I do not see a current limiting resistor for the led in your schematic.
Do you have the specifications of the solid state relays?

Bertus
My experience with SSRs has been with standalone units, which usually accept a wide range of input voltages with no current limiting required (based on a few schematics I've seen, I think they often include a linear regulator to control voltage and/or current to the LED.)

I was initially surprised by your comment, but then looked at a few datasheets for board-mount SSRs and found them to be as you described.

So I suppose the question here is which type of SSR the OP is planning to use...
 

Lestraveled

Joined May 19, 2014
1,946
Buck
Do you understand what bertus and ebeowulf are talking about? Some SSR have specific input voltages that they work at. Some are variable by using a series resistor. Have you selected a model yet?
 

Thread Starter

buck1106

Joined Jul 31, 2015
5
This sounds too complex for what i'm requiring, would a ordinary relay serve the same purpose. What design do you suggest i alter to?
 

Thread Starter

buck1106

Joined Jul 31, 2015
5
Hello,
Are you using this relays?
http://www.ebay.com/itm/Solid-State-Relay-SSR-25DA-25A-250V-3-32VDC-for-PID-Temperature-Controller-TE-/291259297642

That one has a build in current limiting and can be connected as you show it.

Bertus
yes that was the one i was planning on using.
what design do you think is best in order to enable me to see the level of the tank but also make the bore pump (which has a built in shutoff when the line is closed) run within a range of levels
 

Thread Starter

buck1106

Joined Jul 31, 2015
5
Hey guys ive added a bit to my design im going to incorporate it with my small greenhouse to make it worthwhile and as a fun project.
I've done a rough diagram -sorry for the quality first time using the program. A couple of questions what is the best way of stepping down the voltage from 240vac to 25vac for the solenoid or is it best to use a separate relay.
I really appreciate the feedback given so far.

Also i've just randomly allocated the GPIO for now i will have to check which are available as the open sprinkler takes up a large number of ports out of the 40 for RP2.
 

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