Planet Arduino

A lighthouse beams light out to make itself and its shoreline visible. [Daniel’s] lighthouse has the opposite function, using lasers to map out the area around itself. Using an Arduino and a ToF sensor, the concept is relatively simple. However, connecting to something that rotates 360 degrees is always a challenge.

The lighthouse is inexpensive — about $40 — and small. Small enough, in fact, to mount on top of a robot, which would give you great situational awareness on a robot big enough to support it. You can see the device in action in the video below.

This lighthouse uses a common solution to the rotating connection problem: a slip ring. While these are mechanical, commercial units can be relatively reliable. To route all the signals, the slip ring needs six wire capsules meaning there are six wires that logically pass through the rotating part. The drive motor spins at 60 RPM, but there are two sensors 180 degrees apart to double the scanning rate. The 3D printed housing uses PLA and looks great.

Of course, the real trick will be using all this data meaningfully in your robot or whatever is listening to the lighthouse. That, however, is a different topic. If you think two ToF sensors are good, why not try three?

[kodera2t] discovered the VL53L0X Time of Flight sensor and thought it would make a great way to control the operation of a model train without touching it.

The sensor was small enough for an N-gauge train, which translates to 1:148 scale or about 9mm from rail to rail. His idea was to build a tiny control board that could fit inside the locomotive: 10mm by 40mm. His board consists of the ToF sensor, an ATMega328P-MMH, USB-serial, and a Texas Instruments DRV8830 motor driver. he powers the board via the 6V running through the track.

Right now [kodera2t]’s using the ToF as sort of a gestural controller to get the train to start rolling, but one could imagine the sensor could be incorporated into more advanced programming, like having the train speed up on straightaways and slow down on a curve, based on the height of the bridge over it.

We’ve published a bunch of [kodera2t]’s tiny circuit board projects here on Hackaday, including the smallest basic computer, his minimal frequency counter, and his VFD amplifier.