LoLin (WeMos) has (almost) disappeared from radar in favor of the Chinese manufacturer LiLyGo, which markets TTGo boards. However, WeMos continues on its way. LoLin offers us a new W600 development board as well as several Shields compatible with the D1 Min and D32. The SGP30 for monitoring air quality (measurement of TVOC and eCO2), a monochrome ePaper screen with a diagonal of 2.13″.

All shields with a sensor opt for a micro-daughter board to be cut. The TFT I2C Connector Shield expansion board as well as a 4-wire cable (+ 3V, GND, SDA, SCL) in JST SH 1.0mm 4-pin format will be required.

New LoLin W600-PICO

The LoLin W600-PICO is a small development board built around the W600 SoC from Winner Micro (official page). Programming and powering the board can be done via the micro-USB connector. The board is equipped with a conventional USB to CH340 series converter. If necessary, Wemos offers a driver for download.

The W600 is a SoC chip with Wi-Fi connectivity compliant with the IEEE802.11b / g / n standard that integrates a Cortex-M3 processor (32 bit CPU @ 80MHz), 1MB of Flash memory, 288KB of RAM, a transceiver RF. It has several interfaces such as SPI, UART, GPIO, I2C, PWM, I2S, 7816. The W600 supports the PRNG, SHA1, MD5, RC4, DES, 3DES, AES, CRC and RSA encryption and decryption protocols.

By default the W600-PICO comes with the Micro-Python firmware pre-installed. LoLin offers a small tutorial to get started on your WiKi here.

The LoLin W600-PICO is available on the official store for € 2.15 (+ shipping costs).

Pin identification of the W600-PICO

Shield SGP30 for monitoring air quality (TVOC and eCO2)

The SGP30 expansion shield will allow monitoring of air quality. It is fitted with the SGP30 sensor from the manufacturer Sensirion (technical documentation). This miniature sensor (2.45 x 2.45 x 0.9 mm) makes it possible to achieve the CO2 equivalent eCO2 content of 400 to 60,000 ppm from the H2 concentration in the air (note that this is not an exact measurement of the CO2 content. CO2). The SGP30 can also measure the volatile element content (TVOC) in the atmosphere up to 60,000 ppb.

The sensor can be installed on a mini daughter board which can be detached to place the sensor in a more suitable measurement area. It will then suffice to connect the probe to the I2C bus of the LoLin d1 mini using a 4-wire cable (+ 3V, GND, SDA, SCL) in JST SH 1.0mm 4-pin format. A 2mm diameter hole is provided on the daughter board for fixing.

SGP30 support can be done using the Adafruit_SGP30 library. An example of Arduino code is available on GitHub.

/*
  Install Adafruit_SGP30 First: https://github.com/adafruit/Adafruit_SGP30
*/

#include <Adafruit_SGP30.h>
#include <Wire.h>

Adafruit_SGP30 sgp30;

void setup()
{
  Serial.begin(9600);

  if (!sgp30.begin())
  {
    Serial.println("Sensor not found :(");
    while (1);
  }
  Serial.print("Found SGP30 serial #");
  Serial.print(sgp30.serialnumber[0], HEX);
  Serial.print(sgp30.serialnumber[1], HEX);
  Serial.println(sgp30.serialnumber[2], HEX);
}

void loop()
{

  //CO2: 400 ppm  TVOC: 0 ppb
  delay(1000); //Wait 1 second
  if (sgp30.IAQmeasure())
  {
    Serial.print("CO2: ");
    Serial.print(sgp30.eCO2);
    Serial.print(" ppm\tTVOC: ");
    Serial.print(sgp30.TVOC);
    Serial.println(" ppb");
  }
  else
  {
    Serial.println("Error...\r\n");
    while (1)
      ;
  }
}

Communication with the sensor will be via the I2C bus according to the following wiring diagram

Some additional info on the official LoLin WiKi.

The Shield SGP30 is available for € 6.44 (excluding shipping) from the official store.

New 2.13 ” ePaper shield (250×122 pixels)

To make displays for your connected objects, LoLin offers a 2.13 ” diagonal ePaper (eInk) screen with a resolution of 250×122 pixels. The advantage of the ePaper is that it only consumes power when the display is refreshed. The downside to this display technology is that it may take several seconds to refresh (depending on the screen size). It will therefore be reserved for projects that require little updating (for example the weather forecast or an air quality monitoring station).

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The screen uses the IL3897 driver (compatible with the Adafruit_GFX library) installed on a control board integrated on the back of the screen. The screen can be used on D1 mini, D1 mini Pro, D32 Pro development boards. To do this, you will have to use a SH1.0 10-pole female / female cable (as for the 2.4 “TFT screen) via the TFT I2C Connector shield (detailed below in the article). Small regret on this side, LoLin preferred to use a JST connector rather than using the usual header.

Shields updated: SHT30, HP303B, BH1750FVI

LoLin generalized the idea of a pre-cut mini daughter board for all I2C shields:

• SHT30
  • Temperature measurement -40 ° C to + 125 ° C (± 0.3 ° C) and humidity from 0 to 100%
  • Available I2C addresses: 0x44 (default) or 0x45
  • SHT30 Technical Notice
  • Tutorial to get started
  • Official version
• HP303B
  • Measurement of atmospheric pressure from 300 -1200 hPa (± 0.005 hPa)
  • Temperature measurement from -40 to + 85 ° C (± 0.5 ° C)
  • Available I2C addresses: 0x77 (default) or 0x76
  • HP303B Technical Notice
  • Official version
• BH1750FVI
  • Ambient light measurement from 1 to 65,535 lx
  • Available I2C addresses: 0x23 (default) or 0x5C if supplied with 3.3V
  • Technical manual of BH1750FVI
  • Tutorial to get started
  • Official version
• DHT12 – shield is no longer available, replaced by SHT30

SHT30

HP303B

BH1750FVI

TFT I2C Connector for ePaper, TFT and I2C mini shields

Once detached, the mini daughter board should be connected to the LoLin d1 mini via the TFT I2C Connector Shield expansion board. This shield will also allow to connector a TFT or ePaper display to the LoLin d1 mini or D32.

The board has 4 miniature connectors in JST SH1.0 format (connector with 1mm pitch):

• x1 10-pin connector for TFT or ePaper screen
• x2 4-pin connectors for I2C accessories (SCL on D1 and SCA on D2).
• x1 4-pin user connector (3.3V, D4, D3, GND)

The pins are marked as follows

Connector for TFT screen

Connector for SH1.0 10-pole female / female cable