Functional model
Safety Sensor Demonstrator
for safe distance measurement

The trade show demonstrator attracts visitors' attention with over 3,000 installed LEDs and illustrates the operating principle of safe distance measurement using a redundantly implemented radar measurement path. Pre-programmed games and mechanically adjustable sensors invite visitors to discover the advantages of radar technology interactively.

For safe distance measurement, two sensor pairs, each composed of two opposing radar sensors, form a self-monitoring measurement system. When the two lower sensors move in parallel they deliver matching and thus valid distance values. If the difference between the measured values becomes too large, an alarm is triggered automatically and the system is immediately brought to a safe state.

The LPR®-1DHP-291 sensors from SYMEO are used in demanding industrial environments where high robustness and reliability are crucial, for example with dust, dirt and extreme weather conditions.

One example is use in shipyards. Mounted on the crane bridge, the sensors detect and monitor the precise crane position during loading of container ships and ensure the safety of people and equipment under extreme conditions.

To lighten the atmosphere at the trade show booth, two interactive games and an Easter egg were programmed into the functional model:

In the first game, inspired by “Beer Pong,” the aim is to throw a virtual ball into a “cup” of markings with a sensor movement-touch sensitivity is required!

In the second game, “Space Egg,” the player controls a hen (sensor marker) and must position it over an egg (color stripe) to hatch it. The player who hatches their chick first (stripe color change from red to green) wins.

The Easter Egg reveals a beautiful rainbow running light that flows like falling drops of color from top to bottom. It is activated when the sensors are moved against each other for several seconds.

To ensure smooth production of the trade show model, the entire model was designed in detail in 3D.

The construction of the LED tube presented a particular challenge: an aluminum tube that simultaneously serves as the carrier for the LEDs, a ventilated heatsink, and a cable conduit gives the column the necessary stability. In addition, two acrylic tubes acting as diffusers to gently scatter the LED light were integrated. With this combination, both functional and aesthetic requirements had to be met.

The perfect interplay of microelectronics and custom-made mechanics.

Hidden in the base of the functional model is the powerful control electronics that processes the sensor signals and also controls the LED tubes. The centerpiece is an ESP32 dual-core 32-bit microcontroller that is programmed in C++ and produces impressive LED effects at up to 120 FPS. The radar sensors are connected via a CISCO switch over Ethernet.

An Igus plain bearing enables smooth movement of the sensor in the Z direction and reliably prevents rotation about its own axis.

The well-thought-out combination of two tension springs keeps the sensor precisely in the center position. One spring carries nearly the entire self-weight of the sensor, while the second spring catches the remaining weight force only beyond the center position due to its preloading. In this way, an exactly defined central rest position is achieved despite bearing friction and manufacturing tolerances.

A total of 3,000 LEDs of the type WS2812 ECO were installed in two acrylic tubes of the functional model for displaying measurements and light effects. The energy-efficient LEDs are wired in series in a daisy chain, which makes it possible to control all RGB LEDs grouped together with only a few data lines from a single ESP32 microcontroller.

A cooling system with high-quality Noctua PC fans generates a constant airflow inside the tubes and the base. This reliably cools the power supplies and LEDs, ensuring long-lasting performance.

All components with complex geometries were manufactured on a Bambu Lab X1E 3D printer. The carbon-fiber-reinforced filament used, PAHT-CF (high-temperature resistant nylon), is particularly durable and withstands high loads.

To ensure maximum fit accuracy and minimize post-processing effort, all required wooden parts of the functional model were CNC-manufactured and could be assembled directly with precise fit.

A transport box specially designed for the functional model ensures quick setup and teardown and provides optimal protection during transport of the valuable trade show object.

Behind the scenes, work was carried out with passion and creativity. The development and construction of the functional model were a perfect combination of software, electronics and hardware. From precise CAD design through manufacturing by CNC and 3D printing to programming in C++, I was able to contribute everything that makes my engineer's heart beat faster. Especially the programming of the LED effects left a lot of room for creativity and made the project a real highlight.

Already during manufacturing and especially after completion, the functional model provided an excellent opportunity to fully pursue my passion for photography and videography. The individual steps of the production process as well as the impressive lighting effects made the project a fascinating subject for the camera.

... for the SYMEO team at the trade show booth.

Many thanks to the trade fair team of Symeo GmbH from Munich for the trusting and appreciative collaboration. Especially the friendly and warm personal contact and the creative freedom granted during implementation made this project a thoroughly enriching experience. A valuable collaboration that was positive in every respect.

At the SPS trade fair in Nuremberg, the functional model attracts attention. With fascinating LED light effects and interactive games, it invites trade fair visitors to explore the world of radar technology in a playful way.