LEDNET

Develop an IoT based smart city lighting system

ABOUT Lednet

In August 2017, we were contacted by Alkatech with respect to an innovative LED lighting solution. The project charter that they were working on, stated an innovative lighting concept for the city of Genk (Belgium). Each lamp post had to be remotely controllable from a cloud based portal and the refresh rate of the light fixture should at least be 30 frames per second.

The lamp had to be made available on 250 locations in the city of Genk. On some locations, neither ethernet nor a wireless connection was available.

Commissioned for: Alkatech
Project partners: Painting with Light, RMS Engineering
License: Copyright Alkatech 2018
Hardware platform: Raspberry Pi model B + customized extension board
Software platform: NodeJS (PI backend), Google Firebase (backend) & Angular (frontend)

SYnchronous Play

Often IoT solutions require an action to be executed with an exact timing. In the case of LedNet, each individual frame (lasting only for 30ms) has to be played synchronously on all lamps. Network based time solutions like NTP offer a good synchronization but suffer from a lag that causes an offset of typically 30 – 50 ms. 

For this requirement, we advised our customer to rely on a GPS sensor. LedNet obtains very accurate time from the atomic clocks that are inside GPS satellites. LedNet can combine the time it receives through GPS with network based time to make it more fault tolerant.

 

Graceful shutdown

As some of the light fixtures are connected to the streetlight net, a reliable power source could not be assumed. To cope with this challenge, the PI extension board that we developed was  accommodated with 4 supercapacitors. 

The Raspberry PI monitors the state of the supercapacitors through its GPIO pins and performs a graceful shutdown when power is no longer available. 

Art-Net™

Art-Net™ is a protocol that allows for DMX512 data to be transported over a network. LedNet comes with an Art-Net™ recorder that enables recording and deploying a light show. Through this functionality, light shows can be created with advanced lighting consoles like the GrandMA.

In addition to playback recording, LedNet supports live Art-Net™ streaming. On the advent of a music festival, all LedNet fixtures can be connected to the lighting console, through a special Art-Net™ hub.

© All rights reserved