Cosmo_motherboard_schematic.pdf (99924Bytes)
Attached you find the Rev. 0 schematic of COSMA's brain (Eagle). This board connects directly to a FTDI board. As I need MOSI, MISO and SCK also for the micro SD card, I added solder jumpers, so those pins are not connected to the SD card/voltage level shifter while burning the bootloader on the chip.
The board mainly contains:
- Voltage level shifter HEF4050 for the SD card
- MPU 6050 (6 DOF accelerometer/gyroscope)
- I2C voltage level shifter for the MPU 6050 based on BSS138 N-channel MOSFETs
- DS1307 based RTC with backup Lithium coin cell battery
- Connectors for DS18B20 temperture sensor, 8 FSRs, 2 analog sound sensors, ArduEye and EMIC-2
- 1.5A LDO (LM1086) for servos
- 1.5A LDO (LM1086) for 5V devices
- 400mA LDO (MIC2920) for 3.3V devices
Let me know if you have any suggestions, improvement ideas or seeing any design flaws :)