Esp-01 Datasheet (No Ads)

Pro Tip: Keep a PDF of the ESP8266EX Technical Reference Manual on your desktop. You won't read all of it, but you will search for "Deep Sleep" and "GPIO" a thousand times.

has a single blue LED connected to GPIO2, whereas the original ESP-01 often featured two LEDs (power and TX/RX). : Due to the internal pull-ups, the

: Used to determine boot mode. Pull LOW to enter programming/flash mode; pull HIGH for normal operation. GPIO2 : Must be pulled HIGH at boot. ESP-01 vs. ESP-01S: Key Differences esp-01 datasheet

If you’ve been in the IoT hobbyist space for more than five minutes, you’ve likely seen the tiny, unassuming blue board called the . It’s the gateway drug to Wi-Fi-enabled projects, often costing less than a cup of coffee.

Let’s crack open the and translate the hard engineering specs into plain English. Pro Tip: Keep a PDF of the ESP8266EX

Read the ESP-01 datasheet you wire it up. Memorize the voltage requirement (3.3V!). Respect the boot sequence.

The datasheet makes the ESP-01 look limited (only 2 usable I/O pins, needs level shifting, awkward boot sequence). And honestly, for a new project, you should probably buy an ESP32-C3 or an ESP8266 D1 Mini. : Due to the internal pull-ups, the :

Common projects include simple Wi-Fi thermometers, remote-controlled relays for smart home lighting, and serial-to-Wi-Fi bridges that add internet connectivity to legacy industrial equipment. Despite its limited GPIO count (only 2 usable pins), it remains a staple for any developer looking for a minimalist, "set-it-and-forget-it" wireless solution.

3.0V to 3.6V (standard is 3.3V). Note that it is not 5V tolerant for power, although some users report the GPIO pins can handle 5V logic.

Also, note the . The datasheet shows peaks near 300mA. The little voltage regulators on many Arduino boards cannot supply this. You need a dedicated 3.3V regulator (like the AMS1117) to power this module.