Bear Metal Help

Paw

Setting up PX4

Tested PX4 versions

Battery monitoring

PX4 on Karu finds the INA228 on POWER1 and POWER2 at address 0x45 and starts its driver without a parameter. It reports the Paw on POWER1 as battery 1 and the Paw on POWER2 as battery 2.

  1. Set INA228_SHUNT to 0.0003. At the PX4 default of 0.0005 the reported current is 60 % of the actual current.
  2. Set INA228_CURRENT to the highest current PX4 should read, then reboot. At 136 or below PX4 uses the ±40.96 mV input range, which resolves smaller currents. Above 136, up to the default and maximum of 327.68, it uses the ±163.84 mV range. The current reading stops at INA228_CURRENT.
  3. Set BAT1_N_CELLS to the number of cells in the battery.
  4. Set BAT1_V_EMPTY and BAT1_V_CHARGED to the empty and full voltage of one cell. The PX4 defaults are 3.6 V and 4.05 V.
  5. Check the voltage QGroundControl shows against a meter on the battery.

A second Paw on POWER2

Set BAT2_SOURCE to 0 (Power Module) and reboot, then set BAT2_N_CELLS, BAT2_V_EMPTY and BAT2_V_CHARGED as for battery 1. Both modules use the same INA228_SHUNT and INA228_CURRENT.