New Butterfly and Ladybug add-on boards
The point of this kickstarter is to make available easy to build and use STM32L4 development boards at the lowest cost to you. We also plan to build out an ecosystem of peripherals that help you get the most out your new Butterfly or Ladybug.
In the project video we showed one application of an add-on board that can be attached with headers or soldered directly onto the Ladybug. The add-on has a BME280 pressure, humidity, and temperature sensor as well as a VEML6040 red, green, blue, and white ambient light sensor. The application is a super-small, very-low-power environmental data logger.
Many of the add-ons we have already designed for the Teensy 3.1/2 can also be used for Butterfly; Butterfly and Teensy have the same board dimensions and similar (not identical) pin layout. We are also designing many new add-on boards specifically for the Butterfly, and Ladybug too!
Below is an image of the latest add-ons.
To the left is an MPU9250 accel/gyro/magnetometer motion sensor and the BME280 pressure/humidity/temperature sensor designed to mount directly onto the non-USB end of the Ladybug. Coupled with open-source Madgwick or Mahony sensor fusion performed on the STM32L4 host, this add-on board would provide accurate 3D orientation and altitude estimation and would be ideal as a very small inertial navigation device.
To the right is an ESP8266 wifi-enabled add-on board for Butterfly (or Dragonfly) that makes use of a UART bridge between the STM32L4 and the ESP8266 to allow the STM32L4 to communicate to the cloud, send data to a web browser or smartphone, or receive data from another wifi-enabled device. We are working on a method to allow flashing of new programs for the STM32L4 to be accomplished over the air via the wifi connection!
We had to use a 450 mA LDO for a custom version of Butterfly since the ESP8266 requires up to 250 mA to operate the wifi radio. OTA programming compatible with the ultra-low-power of the STM32L4 is better accomplished via BLE, and we are working on a BLE add on which we will describe in a future update.