Dan Kautz
I’m a Hack
I am starting to think of how many ways I can use the micro computers in monitoring and control situations. They can be set up to have their own network IP address and webpage, at least on the home network. It’s called the Spinneret Web Server. Not sure that I would want to make my data available to the world, at least not at this time.
There are just so many wonderful options that these controls can be set up to manage. I’m sure there is a business opportunity somewhere in designing and deploying these devices. I certainly will be finding and deploying my own beyond the RoboBoat Project.
I have returned to my first love of working with computer CPU’s (Central Processing Units). Back when I started there was nothing but assembly. I was working in machine language just trying to make LEDs blink in sequence. Much later on I was writing ham radio terminal programs in MS Basic on the Apple MAC computer. Getting the random serial streams to decode and display properly (using BASIC) was a real challenge. Somehow I got it working very well.
I enjoyed writing computer code for the control system (I/Net) that my real job (office building control systems) allowed. I became involved just as the code writing was evolving from the DOS environment into a higher generation language. Most of the “old boys” didn’t trust the new interpreters. They wanted to stick with DOS. Ha! I had to learn both methods.
I enjoy the process of writing code that works closely with the fundamental CPU process of the computer. I like it more than running a computer application. However, I can live just fine with the simple BASIC interpreters of these computers. Some machine level code (assembly) can be written to speed certain operations. Dedicated hackers (good hackers) can write their entire program in assembly if they desired. Not me, I’ll just give it a poke when I have to. Assembly is just TOO much detail.
The higher power Propeller computer uses a language called SPIN. But that system also recommends Assembly when needed for speed. There are lots of options to fit any need. I love it!
Heck, I may never get the boat built. Not true, I am on a mission there. I’d love to have the boat running simply as the reason to experiment with the programming. And also have something truly unique with which almost no one else is experimenting.
Stand back! You may get injured in all the hacking going on.
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!
More Concept Jabbering
I have thought about this project for some time. I was considering building the boat then figuring out how I was going to control it. I have a good idea what size hull I am going to use for the test bed. Not sure exactly which one though. I’d like to keep cost and initial complexity down by choosing things like only using one motor.
The boat is going to be a stock out of the box kit. No design problems there. Just assemble or build it like all the others of its type. It just has to be big enough for room to work and make changes. Detailing the vessel is a whole other direction I’d like to include in this blog, when the controls become less of the central focus.
The more I thought I realized I was going to tackle the problem from the wrong direction. The controls ARE what is going to be the hardest (most complex) part to design. They need to be the first part of the project. If I can’t get them to work on the bench, then I don’t need to put together a boat.
The computer components are very small and light so size, weight and power usage are no problems. But it is like scratch building a model or maybe a ham radio where there is no complete set of plans or all the parts in a box. No kit with parts already selected that are ready to install. That’s why the communication system is the cutting edge here. I chose the Parallax folks for the hardware to keep the parts shopping at the minimum. They do have a lot of the parts in the box for the robot kits, but no boats in sight.
There is nothing sacred with my choice of supplier. It just works for me
The first version control system will be on a prototyping breadboard and crude looking. That’s why it will be built and tested on the bench, using the 1 milliwatt transceivers and prototype plug in boards. It will be easy to make changes. Soldering parts on a production prototype board is not so friendly to changes.
I am trying to temper my enthusiasm for details by trying to have a suitable plan of action that won’t keep the project on the bench forever. I see so much that can be, that I have to slow down and think what has to be. I don’t need to jump in the water with a fully functional space shuttle. Say… there may be a surplus sale on one of those babies fairly soon…
Here is my thinking. Stage one is a working communication network with rudder control (one servo) and motor control (one motor controller). All inputs from the shore. No more than R/C can do. To prove bidirectional LON communications something will be monitored like maybe a compass heading or motor temperature displayed on shore.
Stage two will be to add the GPS. Then the programming gets tough, like PID loops on the rudder to hold course or turn to a course. More feedback such as true course and distance and true speed can be added to the com link.
Prototype operation can be built into the programming to simulate real world reaction times.
Stage three would be the elimination of the full laptop on the shore terminal. A hand held terminal box Like an R/C radio control supplies all the information using it own embedded microcomputer and a small display. Wow, this could take some time, trying out all the ideas.