CosFly is an ESP32-S3 based drone similar to the Crazyflie architecture style.

I have been a huge fan of the crazyflie system and although Espressif made their "ESP-Drone" I thought I would make one which more closely resembles the crazyflie with some new features like a USB-C port and of course an ESP32-s3 chip enabling ESP-NOW protocol. This also allows for a cheap ESP32 USB dongle to be purchased to allow comms to your own computer if ESP-NOW is desired otherwise simply use Wifi.

This design is you if you want to get involved with micro-drones, explore some research and even do some swarming !

The flight controller has the following features:

• ESP32-S3FN8 chip as the main MCU
• 6-axis BMI270 IMU
• BMP280 Barometer
• Motor control for 4 brushed motors
• BQ24075 battery management chip allowing system power and battery charging over USB-C
• Two red/green LEDs & two blue LEDs indicating charging, power and two being controllable for other options.
• Use of a SPDT switch to ensure top right LED is Green when power is on with GPIO to turn Red at low power.
• PCA9534 GPIO Expander enabling certain LED control and VCOM_EXT (external power switch)
• Expansion headers intended for UART, I2C, SPI with 4 chip select lines, One Wire expansion and two extra GPIO pins
• EEPROM to allow saved memory / configurations (unessential for functionality)
• BOOT / RESET buttons
• ADC for battery measurement reading
• Switch for the 3.3V buck converter that power the ESP32 and sensors.

This is very much a work in progress but the board has been fully tested and works as intended.

Additional items that would be needed are:

• Battery - I have chosen the 3.7V Tattu 350mah 30C battery for the size to fit underneath a battery holder deck / within the expansion header connectors. You will also need a battery connector terminal with wire endings to solder onto the battery pads which feed through the holes below.
• Motors - I went with the motor kit from M5 stack labelled "M5 stamp Fly motors", be careful when choosing motors & battery combinations that will work and won't cause brownout.
• SMD Headers - I found some great 2mm pitch and short 2mm height ones off AliExpress (https://www.aliexpress.com/item/1005013356067352.html?gatewayAdapt=esp2glo)
• Motor holder - dependent on the motor size you will need to make your own custom motor holders again look at crazyflie for some inspiration.

I have personally assembled these drones so check over the pick and place files to match the manufacture and ensure you select impedance controlled boards for the RF chip antenna (50 ohms) and USB differential pair (90 ohms). Some changes could be made for parts for e.g. regional parts which are more available in your country.

In regards to software; I am currently in the process of building this up however, my method is simply to base the architecture of the "LiteWing" ESP drone and adapt the pins and other drivers to match this drone instead. The progress I have made is in this repo:

https://github.com/Cosmo1233/LiteWing/

I am also in the process of making an optical flow deck and multiranger deck which I will post if this gets interest !