The HTML arranges all the elements in the app while the JavaScript is in charge of reading the data from the ESP32 and rotating the arrow.

This web app contains both an HTML and JavaScript code. A text field indicates the heading in degrees. The web app for this project contains an arrow that rotates according to the heading. Also, the HMC5883L needs a 3.3V power supply, hence it gets its power from the 3.3V pin of the ESP32. Since the HMC5883L communicates via I2C, it connects to the SDA (GPIO21) and SCL (GPIO22) pins of the ESP32.

Hence, correct heading should account for this declination. This error, known as magnetic declination, depends on the location of the magnetometer. However, magnetometers detect magnetic north and not true north. Given the magnetic flux densities in x and y axes, the heading is: Heading is the angle from the true north. Measuring HeadingĪs mentioned, this project shows the heading of the device. The wiring diagram for this breakout board and the ESP32 is on the succeeding section. This breakout board makes the HMC5883L easier to interface with a microcontroller. It communicates via I2C and is able to provide magnetic flux density in three axes.įor this project, I am using the HMC5883L breakout board: The Honeywell HMC5883L is a surface-mount, multi-chip module with a digital interface for applications such as low-cost compassing and magnetometry. Note that I am using the NodeMCU-32S which has a different pinout compared to other similarly looking ESP32 boards. I created the code for the ESP32 using the Arduino IDE. The ESP32 is a WiFi microcontroller and is a successor to the popular ESP8266.

Breadboard, Connecting Wires, Power Source.

(And the fact that Adafruit has a zillion parts as Fritzing objects, but I think I will write a Tcl/Tk program to convert Fritzing fxpz files to KiCAD. The only thing Fritzing brings to the table is the Breadboard view. I have designed far more complex boards with KiCAD – Fritzing is far harder to use than KiCAD. Then I discovered that it does not appear to possible to do a copper fill area for power on one side (top) and a ground fill area for the other side (bottom). It was an excessive amout of effort to get those two runs done. There are really only two “routed” nets: SDA and SCL. My KiCad design uses copper fill areas for the power and ground busses: the top layer for +3v3 and the bottom layer for GND. There are exactly 4 nets: SDA, SCL, +3v3, and GND. The circuit I designed uses three I2C breakouts from Adafruit connected to a TTGO-T1 (an ESP32 Devkit clone, available from China for $5/each).

The UI does need some serious work, partitularly when disambiguating what a mouse click refers to (one needs to be overly precise when drawing wires in the schematic view – there is ambigiousness between moving parts and drawing wires). Creating the schematic and breadboard views were not too hard. OK, I just tried to duplicate a KiCAD project I put together recently.

Adafruit esp32 fritzing library