Unasked questions get answered too.
But if I am not present, then I don't have to hear the answer.
In theory.
Okay, not to get all philosophical, but we are taking a closer look at this commercial weather station that Ratso thinks we can back engineer. I thought that wiring up a couple sensors to a microcontroller would be sufficient, but Ratso works at a marine supply store and has spent too much time staring at the stock and getting ideas. Hence the fancy weather station and its soon to be voided warranty. Each of the sensors on this weather station outputs data in different forms. Each sensor has a wire. Getting the data out of the wires and into our microcontroller will not be as simple as hooking the wire up to the microcontroller.
"No, the Hamster wants digital data. It can only read in 1's and 0's. What's coming off the wire is a variable voltage. The Hamster can only interpret that as either a 1 or a 0," I explain to Ratso, who's just brought up the "hook the wire to the Hamster" idea.
"But it's a DC signal," he says.
"Yeah, but that's not digital. We need it in bits. We'll have to use an A to D converter. Once the Hamster reads in the bits, it can interpret them as the actual data. We'll need, like, maybe three bits for that data?" I wonder.
Ratso looks blank. "So we need a three-bit A to D converter? But it's a DC signal."
"Well, yeah, but… I don't know if there is such a thing. Maybe you should ask Dr. Smith?" I know what he's in for, but I say it anyway.
Ratso goes to Dr. Smith's office. Mountain Girl and I work on our part of the project, finishing up the logic for the FPGA part. Then we try to compile and start cleaning up compile time errors.
Time passes.
"I wonder what's taking Ratso so long," MG says.
"I guess he's getting lots of answers. Do you think I should go see? On the other hand, that'll just distract Dr. Smith and it'll take that much longer to get Ratso out of there." Besides, Dr. Smith might well free associate a bit more spec creep for us.
Time passes. We clean out synthesis errors, resolve all the warnings that pop up during the translation process (compiling to hardware has a lot of steps: compilation, translation, synthesis). Continents shift.
I say, "Maybe I should go in there and get Ratso. But—Dr. Smith will come up with more stuff for us to do. God, I'm turning into such a hider, but that's the only way we're going to keep this project under control!"
Time passes. MG and I discuss how the software for other parts of the system need to be modified to work with the hub we're devising. I check my watch. I have class in a while.
Ratso staggers up to the lab and leans on the doorjamb.
"You get an answer?" MG giggles.
"I got the life story. He says we need a twelve bit A to D converter so we get enough resolution. I'm supposed to go ahead and order samples." Ratso lurches over to his computer and goes to the website of a chip manufacturer. He pulls of a screen filled with a full listing of A to D products. "Where do I even begin? What are all these?"
"Why don't you go ask—Pinocchio? He's using a twelve bit one in his project," I say.
Ratso mutters, "We've got sixteen bit ones upstairs. Why don't we just use those? But—oh, no—that'd be overkill, he says."
613 words | February 11, 2005 11:39 PM | Ivory tower