The Tragedy of LM35
on Wednesday, February 21, 2018
Mr. Soni, my lecturer gave us an assignment to assemble arduino circuit that can detect current temperature. What is Arduino? Arduino is an open-source electronics platform based on easy-to-use hardware and software.
After the class had ended, My team (Winaldo, William) and I decided to go with arduino uno and LM35 sensor to create the temperature detector. We also need other things like breadboard, USB cable, jumper wires, and computer with arduino software. However, we didn’t have the LM35 sensor so we bought it in CNC Store in Bandung.
on Thursday, February 22, 2018
After the class had ended, we directly assembled an arduino circuit using LM35 sensor. I kinda forgot how to use arduino since the last time I used it was 2 years ago so I red the manual again…. and searched ‘how to create temperature detector arduino uno lm35 sensor’ on google. We found a really good reference for our project: http://www.instructables.com/id/ARDUINO-TEMPERATURE-SENSOR-LM35/
So, we created the program which basically looks like this
the variable temp is where analogRead stores the value from the specified analog pin. In this project, we used A5 which meant analogRead the value from analog pin number 5.
After that, temp will be calibrated because LM35 sensor doesn’t directly read the current temperature as it is in celcius.
and then, the temperature will be shown in serial monitor throu Serial.print(xx) order and then it will wait for 2 seconds. It keeps looping until whenever.
After the program had been done, we moved on to assembling the arduino circuit. It ended up looking like this:
after that, we loaded the code into to our board and opened the serial monitor. Then,
…WHAT?!
At first, We were happy of the error because we have something to write in our blog. But then the error kept happening and we didn’t exactly know what happened. We assumed three things:
- The jumper wires were broken
We decided to switch the jumper wires…. and nope. Nothing happened. We still lived in 197 degree celcius.
2. The arduino was broken
We tested the arduino by assembling a simple blinking led circuit.
Hey, it worked! so that meant the arduino was working fine.
3. The calibration number is wrong
I don’t exactly believe it because I have read so many references keep saying that the calibration is 0.4 or 1024/500. So, we tried to test the other assumption before testing this one.
4. The LM35 Sensor was broken
on Tuesday, February 27, 2018
It took us 5 days to finally borrow our friend’s sensor……. and BAM! It worked!
So, It is still unbelievable how we just bought the lm35 sensor on wednesday and it was already broken on thursday but hey… at least we have the experiences now.
