Is there any current sensor on the BlueROV2? I want to read current draw from ROV? I wasnt sure how to do it. I want to read it from mavros if possible, not QGC
Hi @axppxsky -
Yes, the BlueROV2 uses a current and voltage sensor, connected to the Navigator. The data is available via Mavlink2Rest, I’m not sure if the ROS BlueOS extension supports reading this information…but if not, I’m sure it might someday!
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i have a pixhawk, not navigator. is that okay?
Check what Revision of the ROV you have? You can find the revision history on the BROV2 Product page at the end of the Technical Details section. If you have a BlueROV2 you should already have a current and voltage sensor integrated, and if using BlueOS the data will be available in Mavlink2Rest with either autopilot. Functionality of the ROS extension should not be impacted by pixhawk vs. Navigator in this context either.
seq: 28405
stamp:
secs: 1707975510
nsecs: 514112281
frame_id: ‘’
voltage: 16.00800132751465
temperature: 0.0
current: -0.6100000143051147
charge: nan
capacity: nan
design_capacity: nan
percentage: 0.8899999856948853
power_supply_status: 2
power_supply_health: 0
power_supply_technology: 0
present: True
cell_voltage: [16.00800132751465]
cell_temperature:
location: “id0”
serial_number
why does current keep showing me negative values
Thanks for this Tony. I’ll cc to @EliotBR to see if it is possible to read the voltage variable in BlueOS as would be good to have an alert event to save the batteries over discharging.
Hi!
For me negative current is discharging/using and positive charging.
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Hi @axppxsky -
The negative current value indicates the direction of the current flow. If your sysem was generating energy and charging the battery, current measured would be positive. The percentage value is based on consumed amp-hours, using the configured capacity for the battery pack. This assumes that the battery is fully charged on system start-up.
okay, thanks for letting me know.
- how can i calculate the power being consumed from the percentage(Amp-hours). Whats the configured capacity?
- 0.62 current draw didnt make sense to me, only 0.62 amps of current was being used when i was running it?
Hi @axppxsky -
- Instantaneous power is current multiplied by voltage. The capacity is configured in the QGC battery menu, under vehicle setup (in mAH.)
- 0.62 amps is a typical current consumption for the system at idle (hotel load.) This will be much greater when the thrusters are working against the water!
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okay, I’m trying to measure the current draw while lighting up the deep subsea lumen lights (i am lighting 2 at a time using arduino), and i see that for several PWM’s the current draw isnt changing at all. Is that normal? These are my observations, you can see for several PWMs the current is same? C1 is the first pair of LED’s and C2 is the second pair of LED’s
LED,CURRENT,PWM
C1,0.6399999856948853,7
C1,0.6499999761581421,8
C1,0.6499999761581421,9
C1,0.6499999761581421,14
C1,0.6499999761581421,16
C1,0.6499999761581421,19
C1,0.6499999761581421,24
C1,0.6499999761581421,27
C1,0.6499999761581421,32
C1,0.6499999761581421,34
C1,0.6499999761581421,35
C1,0.6499999761581421,36
C1,0.6599999666213989,37
C1,0.6599999666213989,38
C1,0.6599999666213989,39
C1,0.6599999666213989,42
C1,0.6599999666213989,46
C1,0.6599999666213989,50
C1,0.6599999666213989,54
C1,0.6599999666213989,56
C1,0.6599999666213989,61
C1,0.6599999666213989,64
C1,0.6599999666213989,67
C1,0.6599999666213989,73
C1,0.6599999666213989,77
C1,0.6499999761581421,79
C1,0.6499999761581421,84
C1,0.6499999761581421,87
C1,0.6499999761581421,92
C1,0.6499999761581421,94
C1,0.6499999761581421,96
C1,0.6499999761581421,101
C1,0.6499999761581421,103
C1,0.6499999761581421,104
C2,0.75,3
C2,0.75,6
C2,0.75,9
C2,0.75,14
C2,0.75,23
C2,0.7799999713897705,29
C2,0.7799999713897705,33
C2,0.7799999713897705,42
C2,0.7799999713897705,47
C2,0.7799999713897705,50
C2,0.7799999713897705,56
C2,0.7799999713897705,59
C2,0.7799999713897705,61
C2,0.7799999713897705,64
C2,0.7799999713897705,65
C1,0.8199999928474426,114
C1,0.7999999523162842,120
C1,0.7999999523162842,123
C1,0.7999999523162842,126
C1,0.7999999523162842,135
C1,0.7999999523162842,139
C1,0.7999999523162842,144
C1,0.7999999523162842,151
C1,0.7999999523162842,155
C1,0.7999999523162842,163
C1,0.7999999523162842,168
C1,0.8299999833106995,172
C1,0.8299999833106995,179
C1,0.8299999833106995,182
C1,0.8299999833106995,186
C1,0.8299999833106995,192
C1,0.8299999833106995,194
C1,0.8299999833106995,195
C1,0.8299999833106995,197
C2,1.100000023841858,68
C2,1.100000023841858,69
C2,1.100000023841858,71
C2,1.100000023841858,77
C2,1.100000023841858,85
C2,1.100000023841858,91
C2,1.100000023841858,95
C2,1.100000023841858,101
C2,1.100000023841858,113
C2,1.100000023841858,120
C2,1.100000023841858,125
C2,1.100000023841858,134
C2,1.100000023841858,138
C2,1.100000023841858,142
C2,1.100000023841858,149
C2,1.100000023841858,151
C2,1.100000023841858,154
C2,1.100000023841858,158
C2,1.100000023841858,159
C2,1.100000023841858,160
C2,1.3700000047683716,170
C2,1.399999976158142,180
C2,1.399999976158142,183
C2,1.399999976158142,188
C2,1.399999976158142,199
C2,1.399999976158142,204
C2,1.399999976158142,209
C2,1.399999976158142,220
C2,1.399999976158142,227
C2,1.399999976158142,240
C2,1.399999976158142,247
C2,1.399999976158142,253
C2,1.399999976158142,255
C2,1.8899999856948853,250
Hi @axppxsky -
Can you share what the time interval you’re increasing the pwm value over is? Have you tried this test in QGroundControl or Cockpit, using the game-controller to increase light brightness while monitoring current? This type of sanity check may help you debug the script you’re using to collect the data. Sharing that would be helpful to the community as well!
i would say the time interval from start to full brightness is almost instantaneous, since i have a frontend with a scroller to send input values.
Would it change anything if i try this using QGC? I’m assuming its the same. and i need to use arduino for my use case
Hi @axppxsky -
I was asking at what interval the data you share was taken- every entry occurs after how many milliseconds?
Testing with QGC would just be a way to verify that your Arduino setup is measuring accurately, but if you don’t have an rov setup that may not be possible…
i see, the entry occurs at around 90 millisconds
also is there a way to increase the precision of this current sensor data? 2 decimal points is looking less for such high speed measurements
i am trying to measure the current draw for every pwm