Even if you aren’t interested in designing a radiant floor zoned heating system, you can study this innovative project and apply what you learn to any number of building control and automation applications. Dalibor Zaric’s Radiant Floor Heating Zone Controller is built around an NXP Semiconductors LPC2134 ARM processor that’s connected to an Echelon Pyxos chip. The project won Second Place in Echelon’s 2007 “Control Without Limits” design competition.
The heat zone controller system (Source: Echelon & Dalibor Zaric)
Zaric provides the following details in his project documentation:
“• Power supply to unit is 24VAC and controller has switching power supply to provide 24VDC for Pyxos network as well 5V for logic, there is 3.3V linear regulator as well.
• There are four relay with 24VAC output to power up thermoelectric zone valve on radiant floor heating manifold. These outputs are protected with 1.85A self resetting fuse to prevent overloading. This block has as well 24VAC/DC dry contact to provide a call for heat to boiler or optional zones pump.
• Pyxos power supply filter and Pyxos chip provides Pyxos network connection for future sensors and thermostats. Pyxos thermostat will be more cost effective than regular LONWorks sensors/thermostats.
• RS-485 driver will provide future Modbus connection for local touch screens or smart home systems with Modbus connections. There is end of line resistors enabled with the dip switches beside connector.
• 3150 Neuron board with 64K flash provides LONWorks connection to the controller.”
The heat zone controller diagram (Source: Echelon & Dalibor Zaric)
Electronics system control, “green design,” and energy efficiency are important topics in industry and academia. Here we look at a project from San Jose-based Echelon Corp.’s 2007 “Control Without Limits” design competition. Designers were challenged to implement Pyxos technology in innovative systems that reduced energy consumption. Daryl Soderman and Dale Stepps (of INTELTECH Corp.) took First Prize for their Solid State Lighting Solutions project.
The Pyxos chip is on the board (Source: Echelon & Inteltech)
So, how does it work? Using the Pyxos FT network protocol, this alternative lighting project is a cost-effective, energy-efficient solution that’s well-suited for use in residential, commercial, or public buildings. You can easily embed the LED lighting and control system—which features SSL lighting, a user interface, motion detectors, and light sensors—in an existing network. In addition, you can control up to five zones in a building by using the system’s fully programmable ESB-proof touchpad.
Another view of the Pyxos chip is on the board (Source: Echelon & Inteltech)
With GPS technology and audio radio interfaces on his personal fleet of bikes, Circuit Cellar columnist Ed Nisley’s family can communicate to each other while sending GPS location data via an automatic packet reporting system (APRS) network. In his February 2012 article, Ed describes a project for which he used a KG-UV3D radio interface rigged with SMD capacitors to suppress RF energy. He covers topics such as test-fixture measurements on isolated capacitors and bypassing beyond VHF.
Photo 2 from the Febuary article, "RFI Bypassing (Part 1)." A pair of axial-lead resistors isolate the tracking generator and spectrum analyzer from the components under test. The 47-Ω SMD resistor, standing upright just to the right of the resistor lead junction, forms an almost perfect terminator. (Source: Ed Nisley CC259)
Repeatable and dependable measurements require a solid test fixture. Although the collection of parts in Photo 2 may look like a kludge, it’s an exemplar of the “ugly construction” technique that’s actually a good way to build RF circuits. “Some Thoughts on Breadboarding,” by Wes Hayword, W7ZOI, gives details and suggestions for constructing RF projects above a solid printed circuit board (PCB) ground plane.
You can read this article now in Circuit Cellar 259. If you aren’t a subscriber, you can purchase a copy of the issue here.