Yet Another Plant Watering System

thingiverse

This system can take responsibility for several plant pots (4 is the default) by keeping the soil/root balls at an individually adjustable level (more about in the details below). It does this by pumping water from a reservoir into the flower pot. If the reservoir is empty, operation will stop to protect the pumps and a LED will remind you to refill the reservoir. Benefits of this system: - 2 watering modes (more in the details) which can be changed on the fly. - Moisture parameters can be changed on the running system. No need to re-code. - Water reservoir is monitored and the system will stop pumps and inform user if empty. - Secured against serious failures of the sensor-pump feedback loop (see below) - sensors will only be engaged when needed, so degradation of the probes will be kept at a minimum possible level. Please don't feel distracted by the variations in the photos. I have used sample images from one 2-pot and one 4-pot system... Update after 1 year of use: --------------------- The YL-69 sensor is still in usable shape (see image). In general they work quite reliable for plants that tend to be kept relatively dry. If you need to keep the pot very moist it is a little bit of fiddling with the flush option to stay at the optimum level. The sensor of the water reservoir has been changed to use adhesive copper strips (see image).The are in service now for several months, work well and are less cumbersome to use than metal rods. Some considerations before you start building this device: --------------------- - I assume you have basic understanding on how to build an electronic device and you know which end of the soldering iron to hold. Updated 2019/04/26: - There is a worst case scenario where the probe in the pot may be disconnected from the system. This means, the YL-38 comparator will default to an "i'm dry" state which could lead to an endless pump cycle. As a mitigation of the problem, the updated Rev.2 of the software checks against the flush runtime (default 60 secs) of the pump. If this time is exceeded, the system will stop operation and the red LED will blink fast to inform you that something went wrong. You should then check the system physically and reset it (power off and on) afterwards to go back to working state. The shopping list (U.S. and German sample links for information provided) --------------------- Please copy-paste the links if you encounter problems. - Power supply, 12V https://www.amazon.com/dp/B01GD4ZQRS https://www.amazon.de/dp/B01DIPM8XU - Arduino Nano https://www.amazon.com/dp/B00NLAMS9C https://www.amazon.de/dp/B07KS2YX64 - 1 Prototype board 5x7cm, male and female headers and screw terminals https://www.amazon.com/dp/B07CK3RCKS https://www.amazon.de/dp/B0728HZHTR - 1 or 2 small switches (1 to enable test mode, the second can be omitted if you don't need to switch operating modes) https://www.amazon.com/dp/B071F4RDHY https://www.amazon.de/dp/B007QAJLDE - 4 Transistors with enough amp to drive your pumps (2N2222 TO-92 or TIP-122, just ensure correct wiring), 4 matching resistors (e.g. ususally 1kOhm for 2n2222 or 2,2 kOhm for TIP-122) and 4 flyback diodes (e.g. 1N4001 or higher) https://www.amazon.de/dp/B014UVI8DU https://www.amazon.de/dp/B00AZUEJRU https://www.amazon.de/dp/B007GP4IIM - 1 red LED 5mm and a 220Ohm resistor https://www.amazon.de/dp/B01N2RH7UA - Aquarium water pump 12V (one for each plant pot) https://www.amazon.com/dp/B00JWJIC0K https://www.amazon.de/dp/B06XBXZFTL/ - flexible hose/tubing, e.g. https://www.amazon.com/dp/B000E62TCC https://www.amazon.de/dp/B06XFNT4WG - Panel Socket - eventually including the plug if the one from the power supply doesn't fit, e.g.: https://www.amazon.com/dp/B0753DSZ7V https://www.amazon.de/dp/B07PN6SZYT - some screws (2mm & 3mm) - adhesive copper strips for measuring water level ---------------------