In case you happen to have an ocean nearby, you’re probably familiar with its rising and falling tides. And if mudflat hiking is a thing in your area, you’re also aware of the importance of good timing and knowing when the water will be on its way back. Tide clocks will help you to be prepared, and they are a fun alternative to your usual clock projects. If you’re looking for a starting point, [rabbitcreek] put together an Arduino-based tide clock kit for educational purposes.
If you feel like you’re experiencing some déjà vu here, this indeed isn’t [rabbitcreek]’s first tide clock project. But unlike his prior stationary clock, he has now created a small and portable, coin-cell version to take with you out on the sea. And what shape would better fit than a 3D printed moon — unfortunately the current design doesn’t offer much waterproofing.
For the underlying tide calculation itself, [rabbitcreek] uses just like in his previous project [Luke Miller]’s location-based library for the ubiquitous DS1307 and DS3213 real-time clocks. Of course, if you also want to keep track of other events on your clock, why not set up calendar events for the next rising tide?
Old fashioned tide clocks were an attempt to predict high tide by timing the rising and setting of the moon. When you looked at one you could see how many hours until the next high tide. [rabbitcreek] wanted to make his own version of the tide clock that does a better job of predicting the actual high tide than those old clocks, which were essentially glorified timers tuned to the moon’s phases.
[rabbitcreek] based his the tide prediction software off of [Luke Miller’s] Tide Clock, which applies location-specific adjustments to the standard lunar clock, taking into consideration such factors as the geographic features (basin depth, etc.) that modify the default timing. [Miller]’s Arduino code includes a library of common locations organized by NOAA station number.
[rabbitcreek]’s project consists of a Adafruit Feather board hooked up to a DS3231 RTC breakout and a HS-225BB servo, which turns the clock’s hand. It’s an 180-degree servo, attached to a hacked-down Actobotics gearbox gearing the servo down 2:1 to permit 360 degrees of movement.
He also wanted his creation to be left to operate unattended for years, theoretically — so solar power was a natch. The face of the clock consists of individual wavers of solar panel glued into a huge clock-like array. The solar cells feed into an Adafruit PowerBoost 500, a TPL5111 low power timer breakout, and a LiPo battery for when it’s dark out.
If you’re looking for more solar clocks check out this one that uses capacitors as hour markers.