The VMX-pi circuit board and official firmware provide inertial and magnetic measurements, with a range, accuracy and update rate as described on this page, as well as a broad range of I/O and Digital Communication capabilities and flexible Power Management.
Note that certain IMU performance specifications are only valid after a start-up Gyroscope/Accelerometer Calibration period, during which time the VMX-pi circuit board must be held still.
Additional details can be found in the VMX-pi-datasheet.
Additionally, the specifications for the connector cables with come with each VMX-pi are also documented on this page.
| Electrical Specifications | |
|---|---|
| Input Voltage: | 6-16V DC |
| Output Voltages: | 5V, 3.3V |
| Protection Features: | Input Voltage Clamps; Under-voltage management; Output Current Limiting |
| Communications Interface: | USB, I2C, SPI, CAN,UART |
| Power Connector: | 2-Pin JST VH Connector |
| USB Connector: | USB Micro-B |
| IMU Performance Specifications | |
| Startup Calibration Period: | 15 seconds |
| Gyro Sensitivity: | +/- 2000 degrees/sec |
| Accel Sensitivity: | +/- 2 g |
| Magnetometer Sensitivity: | 1.3 Gauss |
| Yaw angle accuracy: | ~1 degree of drift/minute |
| Yaw angle accuracy (when still): | ~.25 degree of drift/minute |
| Orientation Data Update Rate: | 4-100 Hz |
| Magnetometer Raw Update Rate: | 4 Hz |
| Magnetometer Angular Accuracy: | +/- 2 degrees |
| Pitch/Roll Angular Accuracy: | +/- 1.5 degrees |
| Analog Input Specifications | |
| Number of Channels: | 4 |
| Resolution: | 12 bits |
| Digital IO Specifications | |
| Total Number of Channels: | 30 |
| Number of Input-capable & Interrupt-capable Channels: | 25 |
| Number of Output-capable & PWM-capable Channels: | 27 |
| Number of Quadrature Encoder Channel Pairs (HW-decode): | 5 |
| Digital Communication Specifications | |
| CAN Protocol (2.0b) | 1mbps |
| SPI Protocol | 8 Mhz |
| I2C Protocol | 400 kHz |
| USB Protocol | 12 mbps |
| UART Protocol | 115 kbps |
| Battery Adapter Cable Specifications | |
|---|---|
| Input Voltage: | 6-16V DC |
| Wire Gauge: | 20 AWG (rated for use at 3A) |
| VMX-pi Connector: | JST-VH |
| Wire Colors | Red (power), Black (ground) |
| Free End: | Stripped and Tinned |
| Cable Length: | 25cm |
| The Battery Adapter Cable provides power for VMX-pi, Raspberry Pi and external devices – and is designed to be easily connect VMX-pi to a robot battery or power distribution switch. | |
| Wall-wart Adapter Cable Specifications | |
|---|---|
| Input Voltage: | 6-16V DC |
| Wire Gauge: | 20 AWG (rated for use at 3A) |
| VMX-pi Connector: | JST-VH |
| Wire Colors | Red (power), Black (ground) |
| Wall-wart Jack | Center Positive; 2.1mm Inner Diameter; 5.5mm Outer Diameter |
| Cable Length: | 25cm |
| The Wall-wart Adapter Cable provides power for VMX-pi, Raspberry Pi and external devices – and is designed to be used with a standard, center-positive AC-DC Adapter which outputs up to 3A at from 6-16VDC. Note: an AC-DC Adapter must be purchased separately. | |