Elle0
Elle0 is a low cost STM32F4 based autopilot. It was developed by 1BitSquared specifically to work with the Paparazzi UAV framework. Elle0 features a very powerful 32bit ARM Cortex M4 micro processor, and is still backwards compatible to the Lisa/M and Lisa/MX you know and love. The footprint of the board is a standard 30.5mm x 30.5mm that was made popular by the nano racer quad community. This makes it easy to replace the autopilot on your racer quad and benefit from the features and stability of the Paparazzi UAV framework. This hardware was developed as part of the Paparazzi UAV framework project and is fully integrated and very well tested. If you are a hobbyist, researcher or system integrator that wants flexibility and high quality at a low cost this is the best choice for you. Because Elle0 was developed by and for the Paparazzi UAV developer community it provides a vast library of modules and subsystems making your path to autonomous flight a breeze. This version of the board supports programming over the built in USB port (DFU bootloader). It automatically detects if you power the board via USB and starts in Bootloader mode, which is a great simplification. The JTAG pins are broken out and can optionally be populated with a standard Cortex 10pin connector. We recommend the G0 GPS module and R0 telemetry radio kit together with the Elle0 autopilot when using it for autonomous aircraft.
Features
- STM32F4 168MHz ARM Cortex-M4 microcontroller with FPU
- 1 Mbyte of Flash memory
- 192+4 Kbytes of SRAM including 64-Kbyte of CCM (core coupled memory) data RAM
- Cryptographic acceleration: hardware acceleration for AES 128, 192, 256, Triple DES, HASH (MD5, SHA-1), and HMAC
- True random number generator
- 3 axis gyroscope (connected over SPI for high speed sampling and low latency)
- 3 axis accelerometer (connected over SPI for high speed sampling and low latency)
- 3 axis magnetometer (connected over SPI for high speed sampling and low latency)
- barometer (connected over dedicated SPI for low noise operation and low latency)
- 1 I2C auxilary sensor connection
- 2 TTL level serial ports for telemetry radio and GPS
- 2 serial input interfaces for remote control receivers (using Spektrum compatible JST connectors)
- 1 USB port for easy firmware upgrade
- 8 PWM outputs/inputs for servos or legacy PPM RC receivers
- 2 Analog inputs for system battery voltage and current measurement
- CAN TX and RX lines are accessible
Warning! The battery voltage measurement pin on the Elle0 does not have a built in voltage divider! DO NOT CONNECT 12V to it!!! You need an external voltage divider depending on the type of battery you use. Please refer to the Battery Monitoring section for details!
Elle0 V1.2 top view
Elle0 V1.2 bottom view
Pinout
Mechanical drawings
Videos
Introduction to the Elle0 Autopilot - Video by the Esden from 1BitSquared
Battery Monitoring
Warning! The battery voltage measurement pin on the Elle0 does not have a built in voltage divider! DO NOT CONNECT 12V to it!!! You need an external voltage divider depending on the type of battery you use.
The Elle0 does not provide a built in voltage divider for improved flexibility. Other autopilots like the Lisa/M come with a 10k Ohm - 2.2k Ohm voltage divider that is good for the use with 3s batteries. This setup does not have good resolution for smaller batteries and can not be used with larger batteries.
In the default value that an Elle0 airframe file will assume is the before mentioned 10k Ohm - 2.2k Ohm voltage divider. To recreate it you connect one side of the 10k Ohm resistor to the battery, the other side of the resistor is connected to the 2.2k Ohm resistor and the voltage measurement pin of the Elle0. The remaining end of the 2.2k Ohm resistor is connected to ground. You can easily modify your uBEC to include the additional voltage divider. To build it by hand you can use industry standard 1/4w through hole resistors.
If you want to measure a smaller battery with greater resolution you will have to adjust the resistor values to have a resulting voltage at the mid junction of not more than 3.3V. The nominal voltage of a fully charged LiPo cell is 4.2V. Also you will have to adjust the multiplication factor in your airframe file.
Schematic
System set up examples
Related Hardware
- Overview: Elle
- G0 GPS receiver: G0
- R0 Sub GHz telemetry radio modem: R0
- UU0 USB to UART adapter: UU0
Where to Buy
Elle0 is available for purchase at the 1BitSquared store.