Functional model
Safety Sensor Demonstrator
for safe distance measurement

The exhibition demonstrator attracts the attention of fair visitors with over 3,000 installed LEDs and illustrates the operating principle of safe distance measurement using a doubly implemented radar measuring path. Programmed games and mechanically adjustable sensors invite you to discover the advantages of radar technology interactively.

For safe distance measurement, two sensor pairs, each consisting of two opposing radar sensors, form a self-monitoring measuring system. When the two lower sensors move in parallel, they provide matching and thus valid distance values. If the difference between the measured values is too large, an alarm is automatically triggered 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, such as dust, dirt and extreme weather conditions.

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

To liven up the atmosphere at the 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” made of markings by moving a sensor - a sense of touch 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. Whoever manages to hatch their chick first (color change of the stripe 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 manufacture of the exhibition model, the entire model was designed in detail in 3D.

The construction of the LED tube posed a special 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. Two acrylic tubes, which act as diffusers to softly scatter the LED light, were also integrated. This combination had to meet both functional and aesthetic requirements.

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. At its heart is an ESP32 dual-core 32-bit microcontroller that is programmed in C++ and generates impressive LED effects at up to 120 FPS. The radar sensors are connected via a CISCO switch over Ethernet.

A plain bearing from Igus 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 holds the sensor precisely in the center position. One spring supports almost the entire weight of the sensor, while the second spring only catches the remaining weight from the center position on due to its preload. In this way, despite bearing friction and manufacturing tolerances, an exactly defined middle rest position is achieved.

A total of 3,000 LEDs of the WS2812 ECO type were installed in the two acrylic tubes of the functional model to display measured values and light effects. The energy-efficient LEDs are connected in series in a daisy chain, making it possible to control all RGB LEDs grouped 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 produced 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 perfect fit and minimize rework, all required wooden parts of the functional model were CNC manufactured and could be assembled with exact fit directly.

A transport box specially designed for the functional model ensures quick assembly and disassembly and offers optimal protection during transport of the valuable exhibition 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 plenty of room for creativity and made the project a real highlight.

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

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

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

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