For those of you tring to squeeze your program into one processor how about a second computer. In the Digikey catalog on page 238 you can order a BS2SX module, the same as in the Invation First Module, and the circuit board to mount it in with the serial programming port. I bet someone like Joe Johnson could even tell you how to communicate beween computers with the serin/serout commands. Total price $79. Any comments?
Although that would be oh-so-cool, rules section “robot” pg 13 says:
*
The custom circuit board may be used to indirectly affect the robot outputs, by providing enhanced
sensor feedback to the Robot Controller to allow it to more effectively decide how to control the robot
outputs.
Custom Circuit boards may not:
o Interfere with the operation of other robots
o Directly affect any output devices on the robot, such as by providing power directly to a
motor, supplying a PWM signal to a speed controller, or supplying a control signal to
the relay module. (High impedance voltages monitoring inputs or low impedance
current monitoring inputs on the custom circuit board connected to the robot outputs are
acceptable, because the effect on the robot outputs should be inconsequential.)
o Be used for wireless communication, such as sending or receiving a signal to and/or
from the alliance station
o Connect to the programming, radio, or tether ports on the robot controller.
However, I don’t see why you couldn’t use a Basic Stamp to give you “intelligent” analog inputs. Just a thought.
You have 16 Digital Input pins, many of which you are probably not using.
If I were going to put a Basic Stamp on the custom board, I think I may decide to use the 16 bits to get some data into the RC’s Basic Stamp. I agree that a better way would be to go through the programming port but this is not a legal option this year.
But, in fact, we are not planning on putting an microprocessors onboard the custom board. We will have some linear stuff and some counters, etc, but nothing that requires programming.
What are others going to put on there custom boards?
Joe J.
When we were planning on building a shooter I was going to use this for my range finder. A emmiter/receiver pair could be connected directly to the Stamp board for feedback on wheel speed (for shooting distance). The supplied banner switches could also be connected directly to the board. And using a Y connector for the servos you could read the direction that they were pointing. After a shot was made the Stamp would read when the wheel was back up to speed and pass this permissive back to the main computer. This would also make a nice current monitor with 16 analog channels available.
I would be interested knowing how one would go about making a counter using the custom circuit board. I thought of a system using a wheel with conductive/non-conductive sectors and having a wire brush sense if it is moving or not. This would require minimal programming and would definately a simple solution.
One might be able to put a thermometer on the control board but it would be limited in purpose and may/maynot be legal depending if you are allowed to have the $100 outside of the board or not. Having an ammeter is also not that useful because you can see the voltage drop using the control system.
(I hit the “close window button” on my Logitech mouse and somehow it submitted the post. Strange. Oh well, that just means it wants me to post it, so I did and I had to modify it.)
You could use the device that you descirbed but there would’t be a sharp transistion between on and off. You would probably see some “bounce” from the brush that would give a false reading.
With a transmitter/ receiver pair you would drill or mill a series of holes in your wheel, each a equal distance apart. Now looking at your Digikey catalog you want a infrared transmitter as your light source mounted on one side of your wheel. Using infrared will eliminate false signals from other light sources. Now mount your infrared receiver directly opposite the transmitter and the slots will block then pass the light through the wheel. Measure how long it takes to see the number of slots you have and you have the speed for one revolution.
Actually, you can use the Basic Stamp II on a custom board to indirectly control parts of the robot by using the analog and digital inputs on the RC to signal the main program as to what action to take. You can have much more complicated program on the custom board the would be free of the delta_t timeout and it’s all legal under the rules.
We are planning to also use hall effect transistors and I also want to include some photo interrupters for speed sensing.
By the way dkeith once the stamp is programmed, you don’t need the carrier board. The “button” command can debounce your inputs or you can use a quad CD4044 S/R flipflop (99 cents) with 1K pull up resistors and avoid programmed debouncing … so socket the custom board for the Stamp, program it with the serial board off robot and plug it in when you’re done… gives you an additional $20 or so for additional parts on board the robot. As for serin serout …there is an example in the Stamp manual that works really well. I’ve coupled two stamps together using the method they described and it works great!
Best Wishes
Steve Alaniz
“What good is technology if you can’t abuse it?” - Ted Forth
Of course why stop at a basic stamp. Digikey sells PIC’s and MPLAB is free from microchip. Build a good, fast second computer.
Ours is nearly done.
Your post was the only mention I could find of MPLAB.
As a first year coach, I was unhappy with the syntax limitations of PBasic. I would love to use C and/or Assembly language. The MPLAB tool from Microchip appears to offer just such a capability.
What are people’s experiences using MPLAB?
Thanks
*Originally posted by Kai Zhao *
**I would be interested knowing how one would go about making a counter using the custom circuit board. I thought of a system using a wheel with conductive/non-conductive sectors and having a wire brush sense if it is moving or not. **
How about using the light sensors we have in the kit (unlimited amount) to read light and dark areas printed onto one (or more) of the wheels. Use two of them and you can get direction and tach. A simple calculation of RPM times wheel circumference would get you distance. This is similar to what the rotation sensors in Lego Mindstorms are doing for FLL teams.
If you needed to measure temperature, an op amp boosting the output of a K-type thermcouple for an analog input would be nice - these thermocouples are available here in the local Auto-Parts-and-Garden-Supplies store (CTC) for $11 for use with their $100 multimeter!
Mplab is a very complete program, including a really good simulator - but to program the chips, you willl need (minimum) a PICStart programmer with ver 2.1 of their programmer software, which (3 times arready) has to be blown into a 17C44 windowed chip, if you buy an older version of the programmer. The old 17C44 must be retained long enough to program its replacement.
There are web sites offering programmers for earlier versions of chips, but MPLab will not speak to them, so programming software must be used, which pulls you away from Mplab.
A very good investment, however. And so much faster than the Stamps (microseconds, not milliseconds)