Posted in OpenSprinkler, Sprinkler Projects on Aug 30th, 2026
Four ways to drive 24VAC sprinkler solenoids from USB-C, with theory, circuit designs, oscilloscope measurements, and practical tradeoffs.
Posted in ESP32, MakeBusiness, OpenSprinkler, Sprinkler Projects on Aug 19th, 2026
Exciting news! We’re getting ready to launch the next generation of OpenSprinkler: AC-Powered OpenSprinkler v4.0, the first built on ESP32. From the outside it looks just like v3.4 — same enclosure and same ports — but inside is an entirely new brain, with a faster processor, more memory and flash space, WiFi 6, analog inputs, […]
Posted in Apps, OpenSprinkler, Sensors, Sprinkler Projects on Aug 3rd, 2026
Some projects take a weekend. Some take a summer. And some take… a little over five years. Today I’m thrilled to make two announcements at once: OpenSprinkler Firmware 2.2.1(5) is officially available, and the Sensor Expander — after a month of pre-orders — is officially shipping. As detailed in our previous New Product Alert post, […]
Posted in Learning Electronics, OpenSprinkler, Sprinkler Projects on Jan 9th, 2026
Introduction More than a decade ago, I published a blog post titled Understanding 24 VAC Sprinkler Valves. In that post, I took a close look at the sprinkler solenoid’s inrush vs. holding currents under 24 VAC, performed theoretical analysis and actual measurements, and explained the difference in the solenoid’s electrical behavior under AC vs. DC. […]
Posted in OpenSprinkler, Sprinkler Projects on Aug 1st, 2024
Recently through a customer I learned about a product called WireSprout, and it only works with the AC-powered OpenSprinkler but not the DC-powered version. Out of curiosity, I looked into why this is happening. So what is WireSprout? Simply speaking, it allows individually controlling 2 zones using a single zone wire. This is useful in […]
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