![]() Which means, of course, that I’m using an Arduino to drive the relays. Why does that matter? Because an Arduino (a small computer) uses 5v on its general purpose input/output (GPIO) pins. ![]() At 250v AC and 10A, it’ll handle far more power than my little pumps could ever draw, but the important part is that it’s activated by 5v. ![]() Since I’m controlling two pumps, I chose this 2-channel relay board from Youngneer. Thankfully, the relay is easy – it’s really just a switch, and the “internet of things” revolution has those things all over the place. It’s basically just a relay, with some sort of magic brain box to tell it when to open and close. Timers of the sort I need are pretty simple critters. Realistically, can I make one of these off-the-shelf timers work if I actually read through the instructions? Probably, but why deny myself the pleasure of building something from scratch that no one needs? Compelling components So, I need a bit more control over the programming. My strawberries need to be watered every 15 minutes or so, all day long, which is way more than 17 on/off cycles. 18 working modes and 17 on/off cycles (like 640k of memory) ought to be enough for anyone.Įxcept when it’s not. They’re all over the place, sporting a wide variety of features and…well, OK, they’re all pretty much the same thing in different packages, but that’s just how 21st century manufacturing works. Timing is everythingįinding 12v timers isn’t difficult at all. Are 12v pumps just inherently more torquey? Maybe, I have no idea. These things have a head height significantly higher than comparably priced 120v AC pumps. I went with these HuiYu 2.4 GPM pumps (which aren’t available a few months later, but this Bayite 2.1 GPM is similar). Not only are there many more available than I was expecting, but they’re surprisingly powerful for very little money. Not good for 8 foot high strawberry towers. Those 120v AC pumps can manage about 6 feet of vertical distance. Every pump has a head height, which is how much vertical distance it can move water – as if it were pumping straight upward. 12v DC isn’t going to power those 120v AC pumps I used before, and those pumps just aren’t up to the task. The generator I’m working on this time is for my strawberry tower. So, I’m making the whole thing run at 12v DC. Fourth (and most importantly), I don’t want to be done tinkering with this design yet, so while it ain’t broke, I’m gonna fix it anyway.Every one that does means dead plants, so this is literally a matter of life and death. Third, more components means more stuff that’ll break down. ![]() A timer and pump connection shouldn’t be this big. A big, boxy inverter, with a big power strip, and a couple of “how do these look identical to the ones we had in the 80’s” mechanical timers takes up a lot of room in the tote. I don’t need perfect efficiency, but I’m pretty sure I can do better than “terrible”, so it’s been irritating me for awhile. the internet not having a very good selection of 12v pumps at the time), but it’s pretty inefficient. This is a simple solution or a relatively simple problem (i.e.
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