![emot-4.jpg](https://modelboatblog.tedatum.com/wp-content/gallery/jmotors/emot-4.jpg "The shaft is a rather small 1/8\\" diameter. There are splines to help hold whatever is installed on the shaft.")
RCS
Hot Props
The Texas heat is killing me in the unconditioned shop. It is keeping me away from experimenting with the Xbee and the Parallax Propeller (computer). The inside temperature in the garage shop has been hovering at 100 degrees while the outdoor has been 105 to 107.
This is NOT for a few days mind you. We have been getting this temperature every single day for over two months steady. Yes, every day.
My new shop fan helps a lot at 80 or 90 degrees but near 100 or over it is just like sitting in a blowtorch. No fun. I tough it out in the morning (on weekends) for a few hours but by 10:00 or 11:00 AM, it’s breaking over 100 again.
Actually the little control computers don’t mind this kind of heat. They are very low powered so don’t generate much heat on their own. It depends on how much power you pull from them. I can’t say that about the PC computer that I use to write the application software. I believe it is maxed out with 105 degree ambient air temp trying to cool the processor, hard drive and other PC components. I had one of my CNC computers (another machine) shut down from the heat after running almost four hours. Luckily I had just finished the part I was cutting and was bringing the HB2 back to home position. I don’t do long CNC runs anymore in a hundred degree shop.
I like the newer Propeller processor. With 8 processors or “cogs” it is a “hot” multitasking little controller. That is figuratively hot. Not environmentally hot. I definitely have it earmarked to be the processor on the boat end. I was thinking about it today, and I am going to also use it on the shore terminal.
I don’t think I need its multi cog power on the shore unit but my thinking is to keep the software programming the same “flavor” for the entire project. I can put the BS2 STAMP to other uses.
I have a few ideas how to design the shore transceiver. It will be a small standalone unit. I was originally thinking of using a PC or Net Book as the shore terminal with just an XBee for the communication. The more I thought I decided a control box would be a better interface and not so expensive (to fix) when getting too close to the water, if you catch my drift. A BS2 would be plenty of computer smarts to run things but as I said above, I’m going to opt for another Propeller.
But hey! Who says I can’t play with my options.
With the Propellers at both ends of the communications I can dedicate one or more cogs in each Propeller to just run the XBees at their best transmission rates. Decision made.
If the Texas heat takes a few days off over the holiday weekend, I plan to get a lot more done with testing the com link. Then I can start designing the Propeller proto boards for the real link.
I also discovered there is a new Propeller multicore processor in the works. It will be bigger and hotter that the present Propeller. But hotter will also be the heat it generates. I suspect it will be more useful in applications where enough “shore” power is available and chip temps can be controlled. I think the Parallax Propeller has a great future and will be useful for a long time.
The Propeller
I can say the Propeller is on the bench. But not the one that spins in the water. This is the Propeller that will serve as the brains of the project. The Parallax Propeller computer chip is actually the larger (.9 x.9 inch) chip near the top of the blue circuit board.
This is a kit for learning how to program and use the Propeller. I am 95% certain it won’t be the same propeller I will use in the actual project. (I’ll buy another, they’re not very costly.) The red and black wires you see on the board, I have just installed. They serve as the “basic wiring” to energize the Propeller on the test board. They are now a permanent requirement for the set-up to power up the processor. You can see the wiring on the box lid.
The USB connection is needed only to program the computer or read text as output in the debug mode. The 9 volt battery powers the Propeller, which incidentally only requires 3.3 volts. There is a regulator included on the Blue board.
I’ll soon have an XBee plugged into the Propeller board.
XBees Are Buzzing
They’re alive! I tell you they are alive!
I got two of the XBee’s talking to each other tonight. The usual things like “Hello World” and counting from 1 to 20. Not much you’re thinking but it is another milestone for me.
One of the XBee’s is directly attached to the USB port on my computer using that tiny little board on which I had to solder the two connectors. The other XBee is on the BS2 Basic Stamp development board. The BS2 computer is actually programed (by me) to talk through the XBee link to my main computer.
They were a few more feet apart but it is a beginning. I moved them closer together for the pictures.
You kiddo’s out there born with a blue tooth stuck in you ear are probably yawning about now, but I have to start somewhere. It will get a lot better and more detailed.
Get to the Point
I said in a previous post my good old standard 15-30 watt soldering iron wasn’t up to the task at hand. The pictures here show the comparison between the old iron and the brand new small point 12 watt iron. I haven’t used it yet but will very soon.
The Xbee Radio Communication Modules
Working with the network system for the Roboboat (RB) project is also a part of my amateur radio interest. It is actually microwave radio and it is one of the areas I have always wanted to explore. The frequency is located within one of the amateur microwave radio bands. It is shared with other services so it doesn’t need to be a ham radio project. Interestingly the frequency of operation (2.4 GHz) is very close the frequency (2.45 GHz) of most microwave ovens. I definitely don’t need to use my radio call sign to identify my cooking. The amateur radio band involved is 2390-2450 MHz. (2.390-2.450 GHz)
Note, at these power levels there is no danger of anything getting cooked.
I have never seen a requirement that amateurs must use ham radio frequencies. We just have to properly operate our radio under the FCC regulations. I am good with that and with a power of 1 milliwatt (0.001 Watts) and a range of a hundred feet, I can’t bother (or cook) too many folks. The “high power” version is 63 milliwatts (0.063 Watts).
Technically, as a ham I can do anything (sensible) I want with these radios on these frequencies. Of course I am going to do nothing but operate them. The only thing I might like to do (someday but not for the RB project) is experiment with feed horns and other antenna options to extend the range. That IS messing with the radio part.
The bottom line is I can claim to be operating an amateur radio station but in fact, these units do not need a license so anyone can operate them. There is no radio “tuning” involved.
The Xbee is far more than just a radio, it is a communication link. The radio communication is totally fixed. The interface the user must establish is talking to the module and reading the information from the module. How the data is handled (by microwave radio) between the modules is totally automated and beyond user control.
That means the method of talking to the module does NOT have to be the same at both ends. This simplifies the application of the product. Half the work is ready to go, no changes needed or are possible to the actual radio part. There are channels that can be selected and they need to be the same but that is setup and not radio tuning. Ain’t technology great!