1 00:00:04,310 --> 00:00:10,430 ‫Welcome to the temperature sensor lab set up lecture for the temperature sensor labs there are several 2 00:00:10,430 --> 00:00:16,450 ‫devices we'll be using will need to be using eight different digits of a seven segment display. 3 00:00:16,640 --> 00:00:24,200 ‫So we have two of the four digit seven semi displays where we're tying all the segments of these displays 4 00:00:24,440 --> 00:00:31,940 ‫together through a 56 ohm resistor that is then connected to the actual FPGA so they can control each 5 00:00:32,420 --> 00:00:36,410 ‫of the individual segments which Winds light up and which ones do not. 6 00:00:36,500 --> 00:00:42,880 ‫And then also each of the digits selects are connected through an individual two and thirty nine or 7 00:00:42,890 --> 00:00:48,720 ‫four endpin transistor but the 470 ohm resistor connected to the base. 8 00:00:48,980 --> 00:00:53,450 ‫And these are all fed out and controlled to the FPGA as well. 9 00:00:53,450 --> 00:00:58,610 ‫So they're controlling the digits and they're controlling the individual LCD segments so we do sort 10 00:00:58,610 --> 00:01:05,120 ‫of a multiplexing operation where we light up each of the segments so fast that one can't tell half 11 00:01:05,150 --> 00:01:13,130 ‫how fast their appears are all lit up simultaneously and for the digits the first digit we're using 12 00:01:13,130 --> 00:01:19,250 ‫to indicate whether or not the temperature is negative or positive is positive or just leave it alone 13 00:01:19,250 --> 00:01:21,010 ‫and won't light it up if it's negative. 14 00:01:21,020 --> 00:01:24,750 ‫What does light up the middle segment indicate a negative sign. 15 00:01:24,950 --> 00:01:30,980 ‫And then the next five digits we're using to represent the temperature where the first three are before 16 00:01:30,980 --> 00:01:34,260 ‫the decimal and the second two are after the decimal. 17 00:01:34,730 --> 00:01:39,500 ‫So the highest temperature we could theoretically display is nine hundred ninety nine point nine nine 18 00:01:39,500 --> 00:01:40,010 ‫degrees. 19 00:01:40,010 --> 00:01:44,990 ‫Now whether you're Fahrenheit or Celsius that's really hot and the sensor will break or melt down before 20 00:01:44,990 --> 00:01:47,970 ‫reaching that point so we don't have to worry about that. 21 00:01:48,070 --> 00:01:52,600 ‫And in the last two digits the next digit we're using to represents the degree sign. 22 00:01:52,600 --> 00:01:59,930 ‫So we're just light up the four top segments and the last digit we used to represent whether were displayed 23 00:01:59,960 --> 00:02:02,040 ‫and Fahrenheit or celcius. 24 00:02:02,090 --> 00:02:04,870 ‫So either display an F or a C. 25 00:02:05,430 --> 00:02:09,890 ‫And so that's how the 7 segment display will be set up and that's what we're going to be using to actually 26 00:02:09,890 --> 00:02:13,100 ‫display our our temperature the measurement that we're reading. 27 00:02:13,100 --> 00:02:19,880 ‫Now we also have the temperature sensor which is a three pin device and it's got one of the pins is 28 00:02:19,880 --> 00:02:21,020 ‫tied to ground. 29 00:02:21,050 --> 00:02:29,240 ‫The other is tied to Vcc or in this case 3.3 volts for all the APJ Develin boards we're using and the 30 00:02:29,240 --> 00:02:30,490 ‫other is the output. 31 00:02:30,490 --> 00:02:37,020 ‫The output is a voltage that changes nearly linearly with temperature. 32 00:02:37,040 --> 00:02:42,340 ‫So you take that that voltage reading and you convert that to an actual temperature. 33 00:02:42,530 --> 00:02:46,290 ‫And then based on that value you can then display it on the Seven same display. 34 00:02:46,350 --> 00:02:51,220 ‫And so in order to actually do the math operations we're going to be using soft core processors. 35 00:02:51,440 --> 00:02:58,040 ‫So we'll be using the microblog software processors for the Xilinx and we'll be using the NIOS soft 36 00:02:58,040 --> 00:03:05,960 ‫core processors for the terrible hours and that is the lab set up for the temperature sensor interface.