Remote Sign Monitoring


Corporate branding is vital to the success of retail stores and hotels, and attractive signage is an important part of the brand message. A customer that designs lighted corporate signs for use on the exterior of buildings needed a way to remotely control and monitor their signs, so they approached Sealevel for a solution. A key goal was to provide an alert with failure data to a back-office server in the event of full or partial failure of a letter in the sign. Sealevel designed a custom embedded computer based on our Relio R9 platform to meet the 0°C to 70°C temperature range and facilitate the customer’s unique I/O requirements.

Application Requirements

  • 12 Relay Outputs with Current Sensing
  • 10/100 BaseT Ethernet
  • Optional Wi-Fi (802.11)
  • RS-485 for Secondary Unit Expansion
  • 24VDC Power
  • 0°C to 70°C Operating Temperature Range
  • Customer Specific Remote Monitoring and Control Firmware

The Sealevel Solution

Using Sealevel’s Relio R9 RISC-based, embedded I/O server platform, Sealevel engineers created a custom system that met all of the customer’s application requirements. The result was a small, RISC-based embedded I/O server that monitors and controls outdoor LED signage through an Internet connection to a host control system. Since our customer lacked in-house software expertise, Sealevel’s software team provided application-specific firmware that allows the embedded I/O server to operate autonomously to report failure data and respond to commands from the host.

Key Design Challenge

Designing an I/O Circuit for Relay Output that Senses Current Draw
A unique I/O circuit was required to allow remote control of the LED sign operation (off/on) and to monitor for failed or dimmed letters. Sealevel designed a hybrid input/output circuit that controls power to the sign through relays and also monitors the current supplied to the sign to determine if all letters are functioning properly. Because the current required for each letter varies due to the size and shape, the circuit is designed to first “learn” the proper operational current of each letter of the sign from which a threshold of full or partial failure can be determined.