Macro Energy

CAD renders of the Macro Supplies autonomous seaweed harvester from four angles, showing overall dimensions of 1.89m by 1.09m by 1.31m. — Design renders of the autonomous seaweed harvester, showing the winch and cutter assembly.

Macro Energy was a startup aiming to turn seaweed into biofuel. Their first product automated the slow, manual process of harvesting it. Farmed seaweed grows along long ropes in the water and is usually cut by hand. Macro's machine was a winch with custom cutters that pulled the rope through and sliced the seaweed off in one pass, like a wire stripper for seaweed.

The winch and cutter prototype in testing, with a length of farmed seaweed rope fed through the mechanism. — The winch and cutter prototype in testing, feeding a length of farmed seaweed rope through the mechanism.

I designed the battery and electrical control system. I worked with mechanical engineers to determine power output, battery lifespan, and safety requirements, and build a solution to meet them.

For the early iterations, the priority was quick execution and low cost, so I used second-hand car batteries instead of the proposed lithium-ion battery pack. Since I was less confident in my high-power electronics skills, I repurposed a motor controller designed for golf buggies and designed a custom PCB and control board to drive it.

Breadboard prototype of the control electronics, built around an Arduino Uno with a digital potentiometer and switching for motor control. — An early breadboard prototype of the control electronics, built around an Arduino Uno.

I delivered two iterations of the system over a couple of months and had a lot of fun along the way.