Phoenix Turbine Builders Club

Introduction to Solar Systems Programming 

June 2005

Last month we covered basic circuits connecting light dependent resistors (LDR's) and phototransistors to PIC processors. We also gave a first-hand look at our 4.5" turbine project using an old snowmobile case), and we announced our new 4.5-inch Experimenter's Tesla Turbine program.

Update: 4.5-inch Tesla Turbine Components & Kits

The 4.5" hot rotors and kits are moving slowly but surely, with some international sales beginning to trickle in. We are extending our rotor kit offer until the end of August, after which time only fully assembled rotors will be available -- so get yours while they last!

Also in August we will continue with the remaining turbine components: bearing case, shaft, and hot rotor case. 

Members who have already ordered rotors and rotor kits will have priority as new components become available.

Adding Intelligence to an Actuator Power Control Unit

Going on to the electronics portion of this month's article, we'll start out by looking at a typical actuator power control unit. Photos 57h, 57i and 57j show an early "antenna positioner" as used in the good old days of large diameter satellite dishes.

These units used electronically controlled power relays to supply both forward and reverse current to the actuator motor to extend or retract a ram capable of about 2,000 pounds of force. As our project progresses, our "smart controller" - using a PIC processor - will interface to this "dumb" actuator controller to automatically aim the dish  toward the sun for optimal heat concentration.

Essential Flowcharts

Continuing from last month's discussion of the PIC processor solar targeting/tracking system, we'll take a look at the basics or introduction to system software development. Before we jump into the actual writing of software algorithms, it's best to organize and plan for the intended results. Not only is it easier to follow a planned itinerary, but there is a lot less error debugging in the long run. It's like writing a term paper or business plan -- the results are usually better when you follow an outline. The outline of a software program is the flow chart.

Since our development system uses both a PC "front end" and an embedded PIC processor "target", our developmental process will include an X86 software module for the PC, and a PIC software module for the reflector aiming system.

Let's begin with a simple set of software modules to read light values from an LDR/phototransistor and report these values to our front end PC.

PIC flowchart 

(get and send light intensity value)

PC flowchart

(capture and display data)

As you can see, the basic principles of program design are straightforward and simple. Next month we'll take a look at translating the flowchart into actual lines of software. Until then, let's keep our grassroots motive power revolution moving forward.