After the success of the Wi-Fi ESP8266 modules, Espressif has not stopped in such a good way and today offers us its successor the ESP32. The first development cards based on the SoC ESP-WROOM-32 very often exceeded €15. Since the beginning of 2017, prices have fallen sharply. It is no longer rare to find maps for about €7 (postage included). It’s happy because the competition is tough against the Raspberry Pi Zero W offers around €11. The ESP32 offer is now very diversified. Here is a brief overview.
ESP-WROOM-32 Technical Specifications
Before going any further, a brief reminder of the technical characteristics (official document) of the ESP-WROOM-32 module. It is the ESP32 module that is most commonly used in development card manufacturers.
- ESP32 Module: ESP-WROOM-32 from Espressive.
- Microprocessor dual core @ 240 MHz
- 4MB flash memory
- WiFi 802.11 b / g / n compliant with IEEE 802.11 compatible with WFA, WPA / WPA2 and WAPI
- Bluetooth 4.0 LE and BR / EDR
- 26x Digital I/O (3.3V)
- 12x analog inputs
- 4 × SPI, 2 × I²S, 2 × I²C, 3 × UART, CAN 2.0, IR, Touch Sensor,
- Temperature sensor
- Cryptographic protection: AES, SHA-2, RSA, ECC, random number generator (RNG)
Here is also the general identification of the pins. As you can see, unlike the Arduino, almost all pins support the Pulse Width Modulation (PWM). On the other hand no evolution regarding the input voltage and output, it is always 3.3V.
Generic ESP32 boards: Geekcreit, Doit
There are some at all prices. Can not test them all. We can just rely on the opinions left by buyers. However, Geekcreit is now a recognized manufacturer. We also find his cards under the name MUST recently. The Geekcreit is equipped with a micro-USB connector for power, programming and debugging. It is very well supported by the Espressive SDK. The ESP32 Generic Module must be chosen. It is available for the price of €8,07 excl. It is very often promoted for about €7.
Known manufacturers: Wemos, SparkFun
If you prefer to stay on familiar terrain, the major card manufacturers now offer cards based on the ESP-WROOM-32 module. The latest is the Wemos LoLin32 presented in this article. It is an excellent choice. Equipped with 4MB of memory and a micro USB connector for programming, it is narrow and equipped with an external LiPo battery connector. It is supported natively by the Espressive SDK. It is available for the price of €6,45 + shipping (8,10 € in my case). This is much cheaper than the SparkFun ESP32 Thing.
In the same category Hornbill, an Indian manufacturer launched a Crowd Funding campaign recently and offers the ESP32 Dev
Special ESP32 Cards
Interesting news, this card-based ESP32 combined with an OLED screen SSD1306 (tutorial). It comes with an expansion card with 10 connectors that appear to be in Intel Grove format. The card is sold under the Wemos brand and moreover it seems to be recognized as such by the SDK. It is offered for about €12,80 (+ €2,21 postage).
This card sold under the name of LoLin ESP32 is available with several expansion cards: DHT11, DHT22, button, LiPo battery 18650 …
Compact ESP32 Cards
If the compactness of the development board is paramount for your project, there are very compact cards. Let us not forget that the ESP32 also incorporates Bluetooth, which makes it possible to make less expensive and more compact setups than starting from an Arduino nano V3 combined with a Bluetooth module HC-06. An HC-06 Bluetooth module alone costs 50% of an ESP32 development card!
In this area, DIY MORE markets this card for example, which measures approximately 2cm side for about €17.90.
Less expensive (€6,90), the LoLin ESP32 is an equivalent of the Wemos d1 Mini. It is sold alone or in kit for €45 including a double base, shield DHT11, DHT22, relay, 4x LED WS2812B, 12x Led ring light, proto
If you do not have a problem with the weld, nothing prevents you from going on the ESP32 + adapter module. We can find kits starting from 5,90 € approximately. Attention to the module, very often it is an ESP-32S which is delivered in the kit.
Build your PCB and integrate an ESP32 module
If you want to develop your own circuits (PCB), nothing prevents you from the ESP32 module alone. A good online circuit design software such as EasyEDA and it’s gone! The module can be found only from about €5 .
- Unpacking Wemos ESP32 LoLin clone with 0.96” SSD1306 monochrome OLED display
- ESP32 MicroPython project with several DS18B20 probes, publish the measurements to Domoticz using the HTTP JSON API
- OLED display SSD1306 in MicroPython, example with a I2C digital barometer BME280 (or BMP180)
- uPiCraft, a MicroPython IDE dedicated to the development of IoT based on ESP8266, ESP32, microbit, pyBoard
- How to reinstall the MicroPython firmware on an ESP8266 or ESP32 with the esptool.py script
- Temperature measurement with several DS18B20 probes, Arduino code compatible ESP8266 and ESP32, publication on Domoticz in HTTP