Sunday May 11, 2014

How to Build Your Own $3.2bln Nest Startup Using Java SE Embedded Tech (Part 6)

After showing how to connect the LCD Touchscreen from adafruit in Part 5 for this Java SE Embedded thermostat project, I figured out a simpler solution for the relays needed to turn on and off the furnace, fan, and A/C of a home heating and cooling system (just like the Nest thermostat).

So, it's time to show how to do a time-honored tradition in high tech start-up prototyping: Refactoring.

I found this cool Single Relay Board from Parallax. It can control up to 120VAC at 10 amps, but we only need to control 24VAC 1 amp relays for the home furnace, fan, and A/C. And most importantly, this Single Relay Board can take a 3.3 VDC signal from a microcontroller or Raspberry Pi running the Java SE Embedded platform (like we are doing in the project). No need for SPI or i2c, just a straight GPIO high value (3.3VDC) from the Raspberry Pi header pins from a Java SE Embedded app will control the relays. Cool!

So, I've got a bit of refactoring to do of my previous blog posts to swap in 3 of these Single Relay Boards (go ahead and order 3 if you are playing along at home). But, it's all good. Refactoring is part of the process of high tech start-up prototyping, right? :-)

Full series of steps:
How to Build Your Own $3.2bln Nest Startup Using Java SE Embedded Tech (Part 1)
How to Build Your Own $3.2bln Nest Startup Using Java SE Embedded Tech (Part 2)
How to Build Your Own $3.2bln Nest Startup Using Java SE Embedded Tech (Part 3)
How to Build Your Own $3.2bln Nest Startup Using Java SE Embedded Tech (Part 4)
How to Build Your Own $3.2bln Nest Startup Using Java SE Embedded Tech (Part 5)
How to Build Your Own $3.2bln Nest Startup Using Java SE Embedded Tech (Part 6)
How to Build Your Own $3.2bln Nest Startup Using Java SE Embedded Tech (Part 7)
How to Build Your Own $3.2bln Nest Startup Using Java SE Embedded Tech (Part 8)
How to Build Your Own $3.2bln Nest Startup Using Java SE Embedded Tech (Part 9)
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Hinkmond Wong's blog on making the Internet of Things (IoT) smarter with Java Technologies

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