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update: my ESP32 classroom now has practice! a few days ago you could explore the board. now you build the circuit yourself on a virtual breadboard: > drag a resistor and an LED into place > draw wires from pin to pin > press Check circuit, then Run, and watch the LED blink in 3D > download the .ino once it works guided mode explains every step, down to why five holes on one row are already connected 3 practice lessons so far: blink, a button and an analog dial. more are on the way free, in your browser

how a banana becomes a button the ESP32 charges and discharges the pin over and over, and the wire makes the whole banana part of that pin. touch it and your body joins in. more capacitance, so every charge takes longer the chip sees the cycles slow down, touchRead() drops below the threshold, and that's a touch

6 bananas, 6 wires, one ESP32. no sensors touch a banana and its twin on screen turns from blue ASCII text into the real fruit. let go and it falls back to text the trick: the ESP32 has touch sensing built into its pins. a banana is mostly salty water, so the whole fruit becomes a touch pad. your body adds a little capacitance when you touch it, and the chip feels the difference

airpods as a mouse is cool, but your hand as a mouse is better a tiny board and a battery on the back of the hand. move it and the cursor follows. click with the thumb on the index finger. it even closes the window how to build one: a motion sensor on the back of the hand turns hand movement into cursor movement. a small button on the index finger is the click. an esp32 with bluetooth sends both to the laptop as a regular mouse no mouse, no mousepad

this is what every computer does, slowed down enough to watch a clock ticks. the chip grabs an instruction from memory, figures out what it means, does it, and moves to the next one the whole program here is five lines: load 5, load 3, add, show the result, jump back. so the number just keeps climbing by 3 your phone does this billions of times a second

a lighter you charge instead of refill how it's built: 1. cut a window in a clear gas lighter and pull out the gas valve 2. fit a tiny lipo cell and a charging board inside the shell 3. wire the cell through a switch to a coil of resistance wire in the old flame spot 4. press the button: current heats the coil until paper catches no gas or flint and matches

would you like to have a tiny robot like this? it shows turn-by-turn directions from your phone and the time, and makes faces while it does. but it's not a product it's a project built by hand with an ESP32 and a small screen a lot of what separates a project from a product is how it's shown. this article is about that

this light can see your heartbeat through your skin a green LED shines into the wrist. blood absorbs green light far more than the tissue around it every heartbeat pushes a fresh pulse of blood through, so for a split second more light is absorbed and less bounces back measure that tiny change over and over and draw it on a screen: one spike, one heartbeat move the light away and the line goes flat same trick as the sensor on the back of a smartwatch. this one is a homemade oscilloscope on a breadboard

engineers undervalue one thing: being seen two of my posts on the same ESP32 topic, ten days apart. same kind of work, very different reach the demo you already built is the proof. what's missing is the first line that makes someone stop. this article shows how

imagine flying a plane from your couch and feeling every roll and turn in your own hands this is the smallest version of that: an ESP32 and a BNO055 orientation sensor on a breadboard tilt the board and the aircraft on screen tilts with it. flip it, and the plane flips the sensor reports its orientation, the ESP32 sends it to the computer, and Blender rotates the 3D model to match no joystick. your hand is the controller

this gives you a sixth sense the closer you get to a wall, the faster it beeps. walk toward anything and you hear the distance shrinking point it anywhere and the screen shows exactly how far things are, and in which direction at the same time a 3D map of the room builds up next to it, point by point, as you move it's lidar, the sensor from self-driving cars. it measures distance with light, and it's small enough to hold in one hand basically a car's parking sensor, but for you and a whole room

wait. this drone can name every object in your house. in real time it flies through a kitchen and tags humans, chairs, tables, the oven, each with a confidence score the model is YOLOv5. "You Only Look Once": it looks at the whole frame in a single pass and returns boxes with a label and a number for how sure it is that's the purple box around the oven and it has one bad habit. it keeps calling everything a TV. a detector only knows the classes it was trained on, and TV is a common one, so any bright rectangle in a dark room gets a low-confidence TV label right now a human still flies it. the AI only watches the next step is turning those boxes into steering: chair ahead, turn. person ahead, stop

you've seen this bug in every car video the wheel suddenly spins backwards. the camera takes pictures too slowly for the wheel, so the picture lies this homemade STM32 oscilloscope has the same limit. it takes 10 million snapshots a second, and past 5 MHz its waves start lying like that wheel safe up to 3.33 MHz, cleanest at 1-2 every radio signal works by the same rule. my guide ↓

wait, a used phone under $200 is a whole computer? this is an S22 motherboard with no screen, no battery, just a fan. it runs a desktop on a monitor same chip class that runs small local AI models. most people throw this hardware away...

you can build a dashboard for almost anything this one is for a rally car: boost, oil temperature, coolant, battery voltage and engine status on a screen the size of a phone case a small board reads the messages the car already sends around, about 165 of them every second, and draws the numbers live for everything the car doesn't report, you add your own sensors. my guide to that is below what would you build one for?

this is what a Tesla looks like if you build it from cardboard no pistons or fuel here, just six tiny electric motors in a V, all pushing one big gear the V shape is borrowed from V6 engines. a real electric car is simpler: a motor turns the wheels through a gear, with no gearbox full of shifting the cardboard version still goes brrr

an ordinary calculator can become a counter for the physical world it already has a display, arithmetic logic, and a running total add an infrared sensor, and changes in reflected light can become counting pulses the trick is the "=" key: on compatible calculators, repeated presses keep adding 1. let the sensor trigger those presses, and the calculator does the counting the same principle can count passing objects, shaft rotations, or winding turns that’s a useful starting point for sensor projects: 1 decide what physical change matters 2 turn it into a clear event 3make the device respond my ESP32 sensor guide below covers choosing sensors, filtering noisy readings, and building that loop yourself ↓