Hi everyone, I'm a computer engineering student and we have this project in which you can hopefully help. I made a proposal of having a time-based self-watering pot for our innovation project in my CoE subject. I proposed this in thoughts of having a fully automated watering system for a plant pot so that you can leave it without doing anything and waters itself.

Now I researched about it and all that pops out are projects with arduino implemented on them. I would like my circuit to be simple and not so overly-complicated with just a bunch of IC to work with. So if anyone can help me out it would be very much appreciated, give some advice in what IC and circuit I could use and the circuitry design. If anyone is wiling to help you can message me at my email (ruppokun@gmail.com) or just reply to this thread.

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If it's in a spot that only gets sunlight for a particular time maybe the use of photodiodes would work.

The use of a half wave rectifier might work if you have tau, the time constant, as a large value. You could just have something activate, causing a single drip, when the voltage is at its peak. You wouldn't want a full wave rectifier though.

You can also use a piece of a soldering board to act as a switch, if there is water to conduct electricity then it should bypass the other portion of the circuit. We did a lab with a rain detector, which we did that with the use of an op-amp too. We were asked to a question to do the opposite as well, which was have the water deactivate the led from lighting up. Instead of a led you could use a motor or mechanical switch to activate in the absence of water. For the soldering board you would solder closed wires for every other portion, I can upload a picture of what I mean for that later too.

I thought of having a trigger circuit using a 555 timer for the electricity to execute "on" state and relay it with an AC water pump so that I could adjust the time interval of the pump to actually work. Is that okay?

Ooooh I thought it was LC, not IC. My bad. I don't know much about timing, as we were only introduced to it in our digital circuit logic course. We never really had to worry about it. The closest thing we did with it was flip flops and registers, but that was more of a physical switch or logic gate that regulated when the output/input was changed. We implemented those use a FPGA as well.

I am more versed in the implementation of circuits without the use of programming.

Hmm googling a 555 timer I get the gist of how it works, since it seems like op amps with a flip flop.

I'm guessing you need to regulate the trigger and threshold, which can be done with a circuit that uses photodiodes if the motor only drips the water slowly. Other than that I can think of having a large tau(time constant) which would spread out the time to charge/discharge. Seeing as when the trigger is (1/3)Vcc maybe a voltage multiplier and/or a half wave rectifier would help with not having lots of low values.

I'm just thinking of ways to make the trigger period be spread out more.

If there is a chip that can convert an ac/dc signal to a low frequency that might help too.

Maybe a use of a audio/sound file that has blurps, or dead spots, can be used with an amplifier to output the trigger voltage. You can think of it as the speaker getting enough voltage to activate the electromagnet to play music/audio, but when there is soft/quiet sounds there is very little voltage going to the speaker. So the soft/quiet spots could be the 1/3Vcc spots and the loud noise could be the 2/3Vcc to activate the threshold.

One could also use something used ever day as the switch, like a coffee pot. Invert the voltage to negative, which would reduce the trigger voltage. When turned off it could have the threshold be back at >2/3Vcc.

Might be hard to do it with just a 555 timer because you'd want something on the order of (a day) or (3 days). A cute hack would be to take a shitty alarm clock, rip out the buzzer and connect the wires to a transistor that trips the watering function. Then you can set the alarm to water at a specific time each day :)

>>5 pretty good idea