ESP32 Maker PCB Sensor box project PCB and box build

 

This ESP32 project uses:

• two metal sheathed DS18B20 sensors (1-wire signal protocol devices) to remotely measure temperature;
• a DHT11 sensor to measure the temperature and humidity at the box top surface; along with
• two tactile buttons for various control purposes; 
• a passive buzzer to provide audible alarms;
• a small I²C connected OLED to continuously display the readings and other control/status events; and
• an optional build feature is the addition of an SPI connected SD card reader for large scale storage of 'logged' data.

Using the ESP32 Maker PCB provides an easy way to interconnect the ESP32 to these devices, but as there are not many connections needed, the PCB need only be sparsely 'populated' as shown below.

 

 

• one of the 5-pin (green) female headers is used to connect the small (OLED) display using I²C (the second is just in case another I²C device is needed later);
• the 'signal' pins for the 2x 3-pin male (black) headers (usually used for servo connections) are used for the DHT11 signal connection and the 1-wire connection for the pair of DS18B20 sensors - it should also be noted that the 'harness' for the pair of DS18B20 sensors are prepared, as shown in the image first right, by putting a single 4.7kΩ 'pull-up' resistor between their connected signal wires and the +'ve power lead, and that each of the +'ve and GND leads from the sensors are paired together so that only a single connection is needed on the PCB within the 'box'.
• the passive buzzer is connected in its dedicated position on the PCB;
• the pair of 3-pin (black) female PWR headers are used to supply power to the DS18B20 and DHT11 sensors;
• a pair of 4.7kΩ resistors, in their dedicated positions on the PCB, are used as 'pull-up' resistors for the tactile buttons;
• 4x 1-pin (black) male headers are used to provide connectors for the buttons which are (remotely) installed in the top section of the box, i.e., they obviously cannot be installed in their usual place directly on the PCB; and
• a 7-pin (black) female header is used as the SPI connection for the option of installing a small SD card reader as shown above 2nd right. It should be noted that more repeatable/stable usage of the SD card reader was only achieved once the MOSI and MISO lines were pulled-up with 10kΩ resistors that were 'built-in' to the harness wiring.

 

The step-by-step stages for the assembly of the 'box' are shown in the series of images below and the 3D print designs are available for download here.

 

the main side walls, the top and the base (not shown) have their fixing nuts 'pulled in' to their openings	partially populated PCB with an underslung ESP32 is installed in the 'box' base and one wall bolted in place	the SD card reader is screwed into its mount on the side wall with the connector openings	the DHT11, buttons and OLED are installed in the 'box' top using screwed in clamp bars
the components in the 'box' top and the pair of DS1820B sensors are connected through to the PCB, then the SD card reader is also connected to the PCB	the second side wall with the SD card reader and the connector openings is 'bolted' to the base	the top is 'bolted' to the two side walls	the assembly is completed by screwing in the two side panels

 

 

More details for the Sensor box project:

 

 

'Complete' projects that can be controlled using the ESP32 Maker PCB:

 

The following links provide more details on various aspects of this evolving ESP32 Maker PCB project development:

 

 

Details for all the Maker PCB projects:

 

 

All the currently available maker project information: