week8

assignment - input device

measure something, to add a sensor to a microcontroller board

for this week's assignment, i decided to measure temperature with THERMISTOR NTC 10KOHM 3750K 1206 NHQ103B375T10. first thing i did was to look at its data sheet, there are some important information to note:

1.it is a NTC thermistor, meaning when the temperature increases resistance goes down

2.this thermistor has a nominal resistance of 10kΩ at 25°C.

3.it has a B-value of 3750K, which is a constant used to describe how the resistance changes with temperature

4.operating range is -40°C to +125°C

i started with a simple board design on KiCad, i chose Seeed Studio XIAO RP2040 as the processor

with help from TA Ray (a big shout out), we decided to use Breadboard PCB for faster prototype. the idea is that power will go to resistor then thermistor then the ground while the thermistor is connected to A0 of XIAO 2040

with code from ChatGPT, we tested it on arduino ide

we tested it with a heat gun. it worked well!

ADC value and thermistor resistance dropped when the temperature increases

however, one thing we were not able to figure out was the temperature readings seems off, the room temperature is around 55 degree

2.0 - TIME OF FLIGHT VL53L1X

Log 1122

i made a second attempt at the input device assignment while working on the final project. Since my final project requires distance sensing, I tested the VL53L1X Time-of-Flight (ToF) distance sensor

This sensor provides fast and accurate ranging up to 4 meters. It operates by measuring the time of flight of invisible, eye-safe laser pulses to determine absolute distances, regardless of ambient lighting conditions or target characteristics such as color, shape, or texture (though these factors can affect the maximum range).

to better understand the sensor, I followed an online tutorial

first i tested on a bread board

it worked well, the serial monitor started showing various numbers as i pointed the sensor towards different objects

then i added an oled

then i made a PCB, again, which i will do it everytime i mill my PCB, shoutout to TA LEO's bitrunner

however, i think my soldering was off, the OLED turned on but the TOF sensor was not working properly :(