Walker Type Nautical Log

thingiverse

A Navigation System Log Clone/Replacement, Built to Generate Approximately 20,000 Pulses per Nautical Mile. Critical Note: Requires User Calibration Before Use in Navigational Applications! Instructions Our Prototype Requires Three 3mm Diameter by 2mm Long Neodymium Magnets Fitted into Each of the Three Holes to Produce Three Pulses Per Revolution. I Installed Two Magnets in Each Hole, Secured with Epoxy. The Hall Effect Sensor is Strategically Placed in the Head Unit, Utilizing an A3144 Hall Effect Sensor. Depending on Your Example, You Might Need to Enlarge the Head's Hole to Accommodate the Rectangular Transistor Properly. Be Mindful When Installing the Component, as it only Detects One Magnetic Polarity. Verify that all magnets are oriented consistently and that the sensor accurately captures their signals. An Optional Thermistor (10k Ohm) can be Fitted to Monitor Temperature. Your Wiring Configuration Might Differ; Consult Raymarine Log Wiring Schematics on the Airmar Sensor Website for Reference. The Head Features a Hole Sufficient to Accommodate 6 Core Telephone Cable, which Works Well with my Setup. My Autohelm St50 System Requires only Five Cores. Two 50mm Long Stainless Steel M8 Cheese-Head Screws Secure the Fins to the Head Unit. These Fittings Must Not Affect the Magnetics and are Designed to Weigh Down the Log in Water. After Confirming Correct Orientation, I Epoxied the Transistor into Place, Then Painted the Entire Device Black. A Drop of Epoxy was Applied to Lock the Cable in the Head. Throughout Development, Multiple Iterations Featured Variations on the Fin Design. This Version Strives to Achieve the Most Accurate 20,000 Pulses per Nautical Mile. Testing Involved Walking Several Meters on a Slipway; however, Real-World Results Might Differ Significantly. To align with Raymarine/Autohelm Standards, I Selected 20,000 Pulses per NM as a target. Calibration Data Collection is Planned for Future Updates. A final Word of Advice: To Avoid Confusion among Marine Life, It's Recommended to Print or Paint the Log in Black Coloration to Disguise it from Fish and Other Organisms.