‫Welcome to the temperature sensor interface demonstration with the Arties the seven development board
‫we have two external four digit 7:7 displays on the breadboard where they're all tied together through
‫a 56 ohm resistors that are fed into the JHP mod port.
‫Each of the digits on the seven second display are controlled through an end to end.
‫Thirty nine of four transistor with a 470 ohm resistor connected to the base.
‫These are all controlled by the J b p mod port.
‫We also have the external aid external voltage temperature regulator which is connected on a separate
‫breadboard that goes into the zero analog input which is the chip kit or Adreno header on the Arties
‫7 development board and we're pulling power from the original.
‫Our breadboard and the way the circuit works is we have this external temperature regulator that takes
‫a temperature and gives a voltage output that is in relation to the temperature.
‫We take the analog voltage reading convert it and do some calculations on it and we will determine what
‫the temperature is.
‫And right now we have we're displaying in Fahrenheit.
‫If I switch my switch 0 to low it will then go ahead and display the temperature in Celsius.
‫Now you'll notice that it takes about anywhere from right away to about a half a second until the conversion
‫takes place.
‫And that's because in the software we have a delay which is approximately a half a second delay where
‫we wait until we actually take another 80 reading and give a temperature output.
‫And so if I toggle my switch one high or low right now it's low.
‫So we're active but if I switch it high all my digits will go to zero and my two digits will go to eight.
‫That's because the microblog is soft core process or we're using by default.
‫When you're when you're not using or controlling it or in a reset state whose output ports are defaulted
‫to zero.
‫And so that's why there's eight express there all the segments are lit up and so to show that this is
‫working crack it will enable it and I'll switch it back to Fahrenheit.
‫And if you look at the temperature you'll notice it says sixty point seventy nine degrees Fahrenheit.
‫If I put my finger and hold it on here you'll see it went up right there sixty two point two five.
‫And the next reading after that should go up even higher 71 and I can hold on to it and I'll keep going
‫up until it reaches approximately the temperature of my hand.
‫Now if I let go and see it may it will start to slow.
‫They drop their 72 and keep going down until it reaches approximate the room temperature again around
‫the 60 degrees.
‫And so you can test this when you actually have the circuit.
‫I would suggest you take it and look at the thermometer or thermostat in your room or the room with
‫chair running in and just to give it a comparison the thermostat in my room says it's approximately
‫61 or 62 degrees.
‫And if you look at the days of this component that it says it it's accurate up to approximately 2 degrees.
‫So and that's exactly what it is right here is kind of hovering around a two to remark of what my thermostat
‫on the House is saying and there are other things you could do if you wanted to really get this even
‫more accurate you could calibrate it.
‫Measure what the actual reading of the 3.3 volt references and use that as opposed to 3.3.
‫But we just use a 3.3 that way we can use it throughout different development boards.
‫So on and so forth.
‫And that is a demonstration of the temperature sensor interface running on the arm of the seven development
‫board.