Assembly of Components (circuit)
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These instructions are for Version 3 of the NodeMCU (identification described in previous article). In Version 1 and Version 2 you have to use VIN and GND next to the MicroUSB connection, instead of VU and G.
!! Important !! Firmware has to be installed before using the SDS011. Only then will the outputs have defined levels.
Below the circuit diagram of how to connect NodeMCU, SDS011, DHT22. It's recommended to use Jumper wires (DuPont cables) of approx. 20cm length - see shopping list. Optionally and also proven more successful with installs is to also connect Pin1 of the DHT22 to 5V (VU). For example with a Y-DuPont cable - see Assembly of parts.
The pins are listed from right to left. When connecting the cables, make sure the connectors are actually on the pins, since DuPont plugs fit in-between as well.
| SDS011 pin | NodeMCU pin |
|---|---|
| 1 | D1 (GPIO5) |
| 2 | D2 (GPIO4) |
| 3 | GND |
| 4 | unused |
| 5 | VU |
| 6 | unused |
| 7 | unused |
The pins are listed from left to right. The grid is front-facing.
| DHT22 pin | NodeMCU pin |
|---|---|
| 1 | 3V3 (3.3V) |
| 2 | D7 (GPIO13) |
| 3 | unused |
| 4 | GND |
The pins are listed from right to left.
| PPD42NS pin | NodeMCU pin |
|---|---|
| 1 | GND |
| 2 | D5 (GPIO14) |
| 3 | VU |
| 4 | D6 (GPIO12) |
| 5 | unused |
The firmware can read IC2 hardware that is connected as follows. It has to support 3.3V.
| IC2 | NodeMCU pin |
|---|---|
| Vcc | 3V3 |
| Gnd | GND |
| SDA | D3 |
| SCL | D4 |
(Only if your power source provides ~ 2A and V > 4.4)
| LM2596 pin | NodeMCU pin |
|---|---|
| LM2596 IN+ | Vin (NodeMCU v1, v2) /VU (NodeMCU v3) |
| LM2596 IN- | Pin GND |
The pins are listed from left to right. The grid is front-facing.
| Sim800l pin | NodeMCU pin |
|---|---|
| GND | OUT- LM2596 |
| TXD | Pin D5 (GPIO14) |
| RXD | Pin D6 (GPIO12) |
| RST | Pin D8 (GPIO18) |
| Vcc | OUT+ LM2596 |
| NET | unused |
Please ensure that you power the Sim800l module with an LM2596 DC Step Down Voltage Regulator to avoid damage to the module. Always ensure your power source can provide at least 2A of current to the GSM module.