Half of a broken circuit is a joint, not a design.
Three seconds on, three seconds of solder, three seconds off. Get the timing wrong and the joint looks finished and is not.
Making a through-hole joint, and telling a good one from the four kinds that fail.
Electricity
Volts, current, resistance and the mistakes that kill parts. 35 pages, true of every board.
35 articles →The other fundamentals trackPower and protection
Fuses, ideal diodes, TVS and lithium cells — every part that sits between a supply and something you would rather not replace. 13 pages, with part numbers.
13 articles →The other fundamentals trackI2C
The two-wire bus nearly every sensor module speaks, from the beginning. Every lesson has a bench in 3D and in a VR headset.
12 articles →The other fundamentals trackMQTT
How a reading gets from a sensor to a phone, a laptop and a lamp without any of them knowing the others. Every lesson has a bench in 3D and in a VR headset.
10 articles →The other fundamentals trackSPI
The four-wire bus that chip after chip uses when it needs to be fast: a clock, two belts of bits, and a light that says who is listening. Every lesson has a bench in 3D and in a VR headset.
14 articles →The other fundamentals trackScreens
Every way a screen is fed, from a two-wire OLED to an eDP laptop panel: how much data a picture is, where the picture lives, and what has to keep moving. Every lesson has a bench in 3D and in a VR headset.
16 articles →The other fundamentals trackTCP and UDP
What a network adds to your data and what it leaves out: one-line cards that may be lost, and a novel cut into numbered strips that is pasted back together. Every lesson has a bench in 3D and in a VR headset.
12 articles →The other fundamentals trackUART
How two devices send bytes down a wire with no clock between them, only an agreement made beforehand: the idle line, the start bit, the data bits, baud, and what happens when the two sides disagree. Every lesson has a bench in 3D and in a VR headset.
12 articles →The other fundamentals trackRS-485 and Modbus
How a serial line is made to carry a long run and a crowd: a difference between two wires, a trunk with many taps, one driver at a time, the ends, and the Modbus conversation on top of it. Every lesson has a bench in 3D and in a VR headset.
12 articles →The other fundamentals trackCAN bus
How many devices share one pair of wires with no master: a hall of desks that shout or stay quiet, who speaks first, how a message is built and checked, what goes wrong, and the two ends of the rail. Every lesson has a bench in 3D and in a VR headset.
12 articles →The other fundamentals trackEthernet
How a cable carries a network: one shared channel and its collisions, what a frame holds and who it is for, hubs and switches, how a link comes up, the MAC, the PHY and RMII, and the three ways an ESP32 gets Ethernet. Every lesson has a bench in 3D and in a VR headset.
12 articles →The other fundamentals trackWi-Fi
How a frame crosses the air: radio waves and channels, why signal is not a bar count, how a network is found and joined, station and access point, sharing airtime, hidden stations, robust versus fast, sleep and security, and the ESP32 on the bench. Every lesson has a bench in 3D and in a VR headset.
13 articles →The other fundamentals trackLoRa
Small messages over a longer link: the chirp, spreading factor, bandwidth and coding, airtime, noise and interference, the rules where you live, collisions, a battery day, LoRa against LoRaWAN, and the ESP32 bench. Every lesson has a bench in 3D and in a VR headset.
12 articles →The other fundamentals trackZigbee
A low-power mesh, not Wi-Fi: the shared radio, three roles, names and joining, paths, a sleepy sensor and its parent, clusters and bindings, security, the controller side, failure, and the ESP32 bench. Every lesson has a bench in 3D and in a VR headset.
13 articles →Next, in the ESP32 bookWires on the board
How two chips agree on what a line means, sorted by what it costs you in pins
9 articles, no board required →Next, in the ESP32 bookMessages on the network
Once there is no wire left to agree about, the question is who talks first
5 articles, no board required →