On the writing front:
I've joined a Science Fiction Writers critique group. Hopefully, they will help me learn why I have a 100 percent rejection rate (I may already know the answer to that!). It's frustrating to submit a story and receive a standard form rejection letter in return. I could just as well throw them over a ten foot high stone fence. It'd be cheaper. I've already received some useful feedback from the group.
I've decided to enter an Science Fiction short story writing contest. The deadline is 01APR2008, up to 8000 words and I'm a third done with the rough draft. There's nothing like a bit of pressure; maybe I'll make it.
My temperature probe project:
Looks like I'll be using a MAX6674 instead of a MAX6675 thermocouple to digital converter. The '74 has a temperature range of 0 - 128 degrees C and an accuracy of 0.125 degrees C as opposed to 0 - 1024 degrees C and an accuracy of 0.25 degrees C. The temperature I'm most interested in is 77 plus or minus 7 degrees C, well within the range of the more accurate MAX6674. Functionally, the two devices are similar; the '74 contains 6,640 transistors as opposed to 6,720 for the '75. Not bad for a chip smaller than a kernel of corn. Internally, the chip contains a couple of amplifiers to raise the voltage levels and control circuitry to allow the measurement of three voltages: each side of the thermocouple and a compensation voltage generated by the chip.
A thermocouple takes advantage of the slight voltage generated in a conductor (wire) when it is heated. Twist two dissimilar wires together and there will be a small voltage difference between the wires that is proportional to the temperature of the heat. The voltage difference generated at the twisted ends (hot end) of the conductors (or wires) will also be present at other (cold) ends where we do the measuring. By measuring the voltage of each wire and subtracting, we get the voltage difference. The voltage difference measurement is proportional to the temperature difference between the hot and cold ends of the wires. The sum of that difference value and the (ambient) temperature value at the measuring end gives us the temperature at the heated end. The MAX6674 generates the compensating ambient temperature voltage.
The (analog) voltage value must be converted to a digital value that the processor, micro-controller, or computer can read and understand. This is accomplished by the analog to digital converter section of the MAX6674. Typically, an analog to digital converter generates a voltage value and compares it to the input voltage value. The generated voltage value starts at zero and is incremented by the same small amount each time until generated voltage is equal the input voltage. A count is kept of the number of times the generated voltage must be incremented before it rises to the same value as the input voltage. This count is the digital value sent to the computer by a series of pulses in response to clocking pulses from the computer.
Using the number of increments, the incremental voltage value, and the voltage to temperature conversion values, the computer calculates the probe temperature.
The output electrical characteristics of the MAX6674 are known in the jargon as 'tri-state.' This allows the outputs of several chips to be wired together thereby saving on the number of I/O lines required from the computer to operate them. Using four MAX6674 chips, one for each meat probe, I'll need a single input line, a single output clock line, and four MAX6674 output select lines.
Thanks to lo5an and his spare parts cache, I have two choices for the processor: a Parallax Basic Stamp, programmed in Basic, and a Modern Device Company Arduino, programmed in C. Since he offers me a choice, I guess I'll take a look at both.
My genealogy studies:
The scanned-images below are from an eight-page loose insert found in the John Brown family bible. John Brown was born in South Carolina near the end of the 18th century. Later, about 1830, he and his family immigrated to Alabama. A copy of the bible insert was sent to me by a one of his descendants who hopes to learn more about John Brown's roots. She sent them to me, not because I also descend from John Brown, I don't, but because I'm studying the Duke family in the part of South Carolina where John Brown likely lived and he married a Ford, another family I'm interested in. Below are images of the first two and the eighth, or final, page of the insert. She thought I might be interested in the first two entries of the final page because one of the Dukes I study is Elizabeth Duke, known to be deceased before 1815 in Fairfield County, SC. It's believed that John Brown lived in Fairfield County, SC.
“Cealy Horne, Daughter of
Elizebeth Duke & Nehemier
Died February 22 -- 1781"
"Elizebeth Duke Wife of
Nehemier Duke Died
on November 31 1813
Aged -- 83 years.”
It's interesting to note that a John Brown was the administrator of Elizabeth Duke's probate. On the 02DEC1818 final probate accounting, one of the legatees of Elizabeth Duke was "Celey Duke, now Horn."
(You may have to click on the picture to enlarge it enough to view the entry.)
This presents a bit of a conundrum between Cealy (Duke) Horn who died in 1781 and Celey Horn, possibly alive in 1818. Usually, when a legatee is deceased, it is mentioned in the record. Notice John Brown's signature. Except for the 'R', it's similar to the writing of John Brown on the first page of the loose insert found in the bible. It's also similar to the the signatures found on Henry Horn's 1822-3 papers, another estate probated by a John Brown. John Brown was described in Henry Horn's will as "my friend and cousin." Below is a composite of the signatures found on those records.
Interestingly, there was a family bible sold at Henry Horn's estate sale. It was bought by Nathanial Parrot, but there is no record of him ever paying for it. It's possible he attended and purchased items at auction on the widow's behalf. The items he bought have that appearance. Another possibility: since the insert was found loose in John Browns bible, it could have been separated from the original bible.
The John Brown of the bible record married Nancy Ford about 1821. If the bible were a wedding present, surely the wedding date would have been mentioned. I believe he obtained the bible afterward. In my opinion the first five entries were entered at the same time and because of that, dated on or after 07APR1827.
We enjoy a late winter afternoon below the lake:
Late winter below the dam. Here's a sample:
This is a sheltered canyon that is a popular stop for small migratory birds. We like to visit at this time each year to have an outing and to see the birds. This year we took our grand-nephew along. We saw no migratory birds, just plenty of aquatic ones that winter-over.</b>