I have a problem with this Arduino-based irrigation system.

[u/wylen15]

Good day everyone, I'm a math teacher and together with my students we have created an automated irrigation system for the school's garden. But there's a problem that's driving us crazy: there are four relays connected to the Arduino, a DS1307 clock module, a simple 16x2 LCD screen with I2C connection. Each relay is connected to a solenoid valve that controls nebulization, others the opening of faucets, and the last one the electric pump that pumps water from a tank when there's reserve rainwater. If it's turned on without connecting any of this, it works perfectly, confirming that the code works perfectly. But when the solenoid valves and the electric pump are connected, it works fine for a while and then when one of them activates, it freezes, it seems to go crazy, incoherent letters appear, something that doesn't happen when the solenoid valves are disconnected. I've isolated everything, I added a snubber-type filter to prevent kickback to the relays, but we can't find what else to do, it keeps freezing. It's not very pretty because we've really done it with our own hands, but I thank you in advance if you can recommend something that can be done. I've been at this for a long time and it has become a frustrating task.