Redwood Systems unstealths Power over Ethernet lighting systems

Today’s San Jose Business Journal carries a story about Redwood Systems, a startup networking company in Fremont, California with a difference. Redwood is a smart-power networking company. Its Ethernet switches supply communications and power to end nodes and those nodes will be lighting fixtures and sensors, at first. Other things related to building control will come later. The company is being very close-mouthed about its technology until May, when it plans a big rollout at the Lightfair show in Las Vegas, however coverage in several media brings enough information to take educated guesses about what’s happening.

First, the company was founded by experts in networking and lighting including Dave Leonard, the company’s CEO, who was formerly General Manager of Cisco’s Ethernet Switching Business Unit and Mark Covaro, the company’s CTO, who was formerly the principal power design engineer for Cisco’s Power-over-Ethernet (POE) platform. So you might guess that two standards, Ethernet and POE are involved here. And indeed, a March 8 article in the online version of LEDs Magazine says as much. Redwood Systems has developed network switches that supply power and networking over a single cable specifically for LED lighting systems. The LEDs Magazine article mentions 60V @ 350mA power, which roughly corresponds to standard POE specifications, so it’s not much of a stretch to assume that the company is planning to adopt standard POE protocols even though none of the company’s literature specifically mentions Ethernet or POE. Adopting these standards is certainly one way to assure luminaire manufacturers of a ready supply of controller chips for all of the LED lighting fixtures they’ll need to develop. Otherwise, the industry would need to develop yet another new set of power+communication chips and there are plenty of those already.

Next, the LEDs Magazine article mentions that Ethernet Category 5/6 cable runs of 100 to 200 feet can deliver adequate power to lighting fixtures (one per cable) and more expensive 18-gauge wiring is needed for longer runs to 100m. The Cat 5/6 cable specification again closely ties the Redwood Systems’ technology with Ethernet and POE. As mentioned in an earlier blog, the ability to run low-voltage wiring for light fixtures rather than electrician-installed, government-inspected Class 1 ac power cables greatly reduces installation costs, which helps to compensate for the increase in the cost of the dimmable LED lighting fixtures compared to incandescent, fluorescent, and gas-vapor lighting fixtures. One fixture vendor clearly involved appears to be LED vendor Cree.

Redwood Systems is targeting the huge market for green lighting solutions. According to a White Paper on the company’s Web site, commercial buildings will use approximately 400 billion kilowatt-hours (BkWh) of primary energy for interior illumination this year. Further, says the White Paper, fully 75% of that energy is wasted because the lighting is being applied where it’s not needed: during the day when ambient light is more than adequate or when only a little supplemental lighting is needed to fill in darker areas and at other times when there’s no one around so illumination isn’t required. Redwood Systems’ smart sensing technology can profile lighting fixtures and the area being illuminated and then control the associated lighting network to light only where needed and to provide only as much light as needed, thus substantially reducing power costs. The ceiling-mounted network sensor incorporates ambient and task light sensors, a 360-degree PIR motion sensor, an ambient temperature sensor, and current and voltage sensors for smart control of the associated lighting fixture. These sensors allow the system to self-calibrate lighting levels and, combined with the low-voltage power distribution, allow the installation and replacement of lighting fixtures into live lighting networks.

The irony of using dc to power lighting, a battle Thomas Edison lost more than 100 years ago to Westinghouse, isn’t lost on Redwood Systems. “Edison was right!” proclaims the company White Paper. Well maybe not then, but maybe now.

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One Response to Redwood Systems unstealths Power over Ethernet lighting systems

  1. stieglitz says:


    Thank you for the write-up on our company, Redwood Systems. To be clear, we do NOT intend to utilize Power-over-Ethernet in our networking platform for LED lights. Simply put, both the “P” and the “E” are wrong.

    Wrong P. Practically all new LED fixture designs for lighting (outside of automotive industry) utilize constant current power architectures. Since POE is a constant voltage architecture, you would need voltage-to-current source conversion (drivers + costs + added losses) at each fixture if you intended to power them remotely with POE. Our architecture chose a purpose-build power design with constant current to enable the fixtures to remotely connect to the engine (power supply + controller) without any additional power conditioning at the fixture end.

    Wrong E. In general, we needed a networking protocol that was simple, low cost, with the appropriate latency, appropriate bandwidth, for the applications of lighting control and sensor data collection. While Ethernet is certainly a robust, standardized, and high bandwidth/low latency approach, we didn’t like some of the cost structure entailed in an Ethernet fabric. Instead, Redwood has invented a very simple, reliable, low latency communication method that is incorporated inside the power delivery. We are still keeping that method under wraps, but suffice to say that we think it has strong competitive advantages in both performance and costs over any other method of wiring/powering/communicating to lights.

    If you are ever in the Bay Area, you should swing by for a visit and demo.

    Jeremy Stieglitz
    VP Product Management and Marketing
    Redwood Systems

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