I Built a Neural Network's First Neuron From Scratch — the 1958 Perceptron

Before transformers, before backprop, there was one neuron — Frank Rosenblatt's 1958 Perceptron. Build it and you understand the atom that every deep network is made of.

This is Day 1 of DeepLearningFromZero: neural nets built from a single neuron up, no framework magic.

A neuron is shockingly simple

Take inputs, multiply each by a weight, add a bias, then apply an activation. The original used a step: output +1 if the sum is ≥ 0, else −1.

let w = [Math.random(), Math.random()], b = 0;