AspirinIMU

Aspirin IMU

The next generation flat multi degree of freedom inertial measurement unit. It uses digital 3-axis sensors which allow for a very small size and price. Other features include onboard voltage regulators, EEPROM for storing calibration data and extra sensors such as a barometer.

Hardware Revision History

Version #	Release Date	Release Notes
v2.1r1(current)	08/2012	2nd Gen Minor Revision
v2.1	03/2012	2nd Gen Production Release
v2.0	11/2011	2nd Gen Prototype
v1.5	04/2011	Updated Production Release
v1.4	03/2011	Prototype Update
v1.3	08/2010	Initial Production Release
v1.2	07/2010	Prototype Update
v1.1	07/2010	Prototype Update
v1.0	07/2010	Initial Prototype

Features

3-axis accelerometer
3-axis gyroscope
3-axis magnetometer
Onboard voltage regulation
Onboard I2C EEPROM
Onboard barometer (v2.1)
Standard footprint across versions
Single PCB flat form-factor
Fits directly onto Lisa/M, carriers for Booz and Lisa/L, or for LPC21xx integration

**Aspirin Feature Matrix**
Version	Accelerometer	Gyroscope	Magnetometer	Barometer	Regulators	EEPROM	Comments
v2.1	MPU-6000	MPU-6000	HMC5883	MS5611	1x 3.3V (LP2992)	yes
v2.0	MPU-6000	MPU-6000	HMC5883	none	1x 3.3V (LP2992)	yes
v1.5	ADXL345	IMU-3000	HMC5883	none	2x 3.3V (LP2992)	yes
v1.4	ADXL345	IMU-3000	HMC5883	none	2x 3.3V (LP2992)	yes
v1.3	ADXL345	ITG-3200	HMC5843	none	2x 3.3V (LP2992)	yes
v1.2	ADXL345	ITG-3200	HMC5843	none	2x 3.3V (LP2992)	yes
v1.1	ADXL345	ITG-3200	HMC5843	none	2x 3.3V (LP2992)	yes
v1.0	ADXL345	ITG-3200	HMC5843	none	2x 3.3V (LP2992)	yes	Also has SC18IS600 SPI-I2C interface

Note: Aspirin 2.1 comes in several population versions. The current version available at http://thequadshot.com has the MPU-6000, HMC5843, and MS5611-01BA03 mounted. You can find the list of fitted sensors on Aspirin 2.1 in the eeprom block 4.

Aspirin V1.4 IMU front
Aspirin V1.4 IMU back
Aspirin V1.4 IMU on Lisa/L compatible carrier board
Aspirin flat carrier board for Lisa/L (without IMU mounted)

Aspirin IMU 2.1 bottom side
Aspirin IMU 2.1 top side
Aspirin IMU 2.1 top side no barometer mounted
Aspirin IMU 2.1 top side no barometer and no magnetometer mounted

Pinout

Note that Aspirin uses a standard footprint and pinout across all versions, with certain exceptions. The chip select (CS) and interrupt (Int) pins are not always assigned to the same devices. A good example is with the introduction of the MPU-6000 device. Check the schematics for details.

Warning: When mounting Aspirin on Lisa/M note that the pin labeled GND on Aspirin (in the right upper corner on the following picture) is connected on Lisa/M to GYRO_SS. To prevent a software error induced shorting of the Lisa/M GYRO_SS pin to ground, remove the castellation or remove the connection on that pad.

In the v2.1r1 versions of Aspirin ("R1" silkscreened onto PCB) the right upper GND pad was changed to Not Connected, (marked RESV in the below image), resolving the issue.

Note that the 12-pin connector pinout of the Booz/breakout carrier (center) is reversed with respect to the Lisa/L flat carrier (right). This is because the Booz carrier mounts to Lisa/L with the Aspirin underneath the carrier (e.g., Z axis pointing toward Lisa/L), and the flat carrier mounts to Lisa/L with the Aspirin on top (e.g., Z axis pointing away from Lisa/L).