Automatic weight based watering system

Other Hardware Science and Measurement
1

Dear Arduino community,

as I'm new to the world of Arduino I have a question (unfortunately without much knowledge about Arduino itself). I'm looking for an option to make an automatic watering system for a large number of plants based on the weights of the pots. How I would like to have it working:

  1. Pots are weighted 2 specified times a day (each pot has it's own weight sensor), this data is stored either on SD-card or online

  2. After weighing, the pots are watered until a specified 'optimal' level, based on weight. The system should automatically stop watering when the optimal weight was reached

  3. The final weight of the pots is also recorded and the data is again stored

The plants don't have to be watered simultaneously, so I guess one (a solenoid?) pump can suffice?

For the weight sensors I was thinking of load cells that can go up to 10 kg each + HX711 amplifiers. What would be necessary to operate a pump?

Is this possible to do with 100 plants? What would be the best way to reach this goal? If needed I can subdivide the 100 plants and make 5 identical systems for 20 plants.

Does someone has suggestions how to start and what to include in the circuit?

p.s.: I know there have been automatic watering systems with Arduino, but those seem to be using moisture sensors and also a very small amount of plants

2

Your scheme most likely won't work as the plants themselves as they grow gain a lot of weight, totally upsetting your watering weight system.

Start with one plant. See if it works. Then think about how to scale it up.

3

Thanks for the reply! Indeed, the weight gain of the plants is important, therefore we will have harvests of plants at different times to see the gain in weight for the plants over time and take this into account. I can imagine that this is just a matter of programming and measuring, which is not really my problem here.

The problem is more in which hardware to use and if it is possible to scale it up to 100 plants. Any thoughts?

4

You kinda list it out already. Weight sensor, Arduino board of sorts (if you want WiFi look into the ESP8266 based boards such as NodeMCU or WeMOS D1 Mini), driver for your solenoid or pumps.

What weight sensor you need depends on the expected weight, required accuracy, size, waterproofing, etc.

Of course it can be scaled up - how to do this depends on which sensors and controller and so you choose.

What solenoid/pump driver you need depends on your selection of solenoid/pump.

With these numbers a custom PCB for each plant becomes an interesting option as well. Makes scaling up a lot easier on the controller part, just make sure there's enough power available and that part will do fine.