moodbot

i wanted to build something that felt alive, not just another screen. it was also my first time with an arduino, so it took about a thousand tutorials, and it was a lot of fun.

it's a classic hobby robot, built over three days from parts most starter kits have:

part	what it does
esp32	runs its own wi-fi network and the control page, and draws the face
arduino uno	drives the motors and reads the distance sensor
l298n motor driver	switches the two motors on and off
hc-sr04 ultrasonic sensor	measures how far away the nearest thing is
128×64 oled	the face

you join its wi-fi from your phone, open a page and drive it with arrow buttons. the face is a few drawn shapes with a random blink, and you pick the mood on the same page: happy, sad, angry, curious, excited or sleepy. the only mood it picks on its own is curious, when something's in its way. in auto mode it drives forward, and when something is closer than 25 cm, it backs up and turns a random way. the motors are just on or off. there's no speed control.

the hard part was the link between the two boards. the uno talks to the esp32 on pins 0 and 1, the same serial line its usb uses. so i couldn't use the serial monitor to see what it was doing, and every upload meant unplugging wires first. i'd run everything from the esp32 alone, so there's no link to debug.