The general idea of my project is to create a circuit which reads the temperature from a NTC sensor and displays it on the computer screen. I created a thread a few months back as I needed help to start my thermistor project (https://forum.allaboutcircuits.com/...ridge-instrumentation-amplifier-stuck.158439/). I am now stuck as I have no idea how to progress, so here's where I'm at:
Besides that, I also have no idea how to connect all of this to a multiplexer as I'm required to do in order to manually (????) switch between the 2 signal conditioning circuits. AFTER THAT I'm even more confused as I have no idea how to connect all of this to my arduino / arduino's ad converter (even though that's the least as I have made lots of research on that topic and I am used to code arduinos in other subjects).
I am sorry if something is hard to understand but I'm up to explain things better in order to learn and get the best out of this project on my evaluation day.
- As you can see from picture nº1, I've successfully built a Wheatstone Bridge + Instrumentation Amp. circuit and the outputs are correct (for a 55ºC - 150ºC temperature gap, I successfully achieve the [0 ... 5]V gap required).
- Picture nº2 shows both the Bridge and the I.A. output voltages depending on the current temperature, everything fine!
- I then proceeded to build 2 signal conditioning circuits (as shown in picture nº3) as I was required to break my I.A. output in 2 parts (this was made so that 1 part would be more accurate (55ºC - 95ºC to a [0...5]V gap) than the other (95ºC - 150ºC to a [0...5]V gap). My commutation point is 95ºC, 3.25V ).
- Picture nº4/5 shows both outputs according to their respective temperature gaps. As you can see, the graph in picture 4 is way more linear than the other, making it easier to read small temperature changes.
- Given that I'm choosing one of the two signal conditioning circuits, I had to build a non-inverting voltage comparator with hysteresis (picture nº6) in order to compare my commutation point voltage (3.25V) with another voltage (after following my teacher's explanation + calcs, I figured out that the other voltage was 3.25V ± 55mV). Can attach my calcs later if needed.
Besides that, I also have no idea how to connect all of this to a multiplexer as I'm required to do in order to manually (????) switch between the 2 signal conditioning circuits. AFTER THAT I'm even more confused as I have no idea how to connect all of this to my arduino / arduino's ad converter (even though that's the least as I have made lots of research on that topic and I am used to code arduinos in other subjects).
I am sorry if something is hard to understand but I'm up to explain things better in order to learn and get the best out of this project on my evaluation day.
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