Power consumption in pib

Owned by Jürgen Baier
Dec 13, 2023
3 min read

This page shows pib’s power consumption detailing each power supply output and each actuator input. First table shows pib’s power supplies abilities, second table shows actuators needed input and third table shows how much power each “joint” of pib use.

  1. Power supplies

 

Voltage

Current output

Total power

Required

Availability in kit

 

Voltage

Current output

Total power

Required

Availability in kit

Main power supply for Tinker forge chips and motors

7.5 V

6 A

45 W

✅

✅

Power supply for Raspberry Pi

5 V

3 A

15 W

Optional but recommended

✅

Power supply for LCD

5 V

3 A

15 W

✅

❌

  1. Needed input

 

Voltage

Current output

Total power

Used power supply

Remaining

 

Voltage

Current output

Total power

Used power supply

Remaining

LCD screen

5 V

700 mA

3.5 W

 

 

Speakers

5 V

700 mA

3.5 W

 

 

Optional: fan

5 V

200 mA

3.5 W

 

 

Total

5 V

1.6 A

8 W

LCD supply

1.4 A, 7W

Raspberry Pi

5 V

1.3 A

6.5 W

 

 

USB dongle for keyboard and mouse

5 V

150 mA

0.75 W

 

 

USB microphone

5 V

0.002 mA

0.0001 W

 

 

Oak d-lite camera

5 V

1 A

5 W

 

 

Total

5 V

2.5 A

12.5 W

Rpi supply

0.5 A. 2.5 W

11 kg.cm motor

7.5 V

100 mA

0.5 W

 

 

25 kg.cm motor

7.5 V

250 mA

1.2 W

 

 

Total

7.5 V

(250x10) + (100x18) = 4.3 A

32.25 W

Main supply

1.7 A, 12.75 W

  1. Joints and parts of pib usage

 

Current range

Power range

Safe

 

Current range

Power range

Safe

1 finger

100 - 200 mA

0.5 - 1 W

✅

1 Thumb (2 parts)

200 - 400 mA

1 - 2 W

✅

Total for 1 hand

0.8 - 1.2 A

4 - 6 W

 

Head Yaw (Z-axis)

100 - 200 mA

0.5 - 1 W

✅

Head Pitch (X-axis)

300 - 400 mA

1.5 - 2 W

✅

Total for head

0.4 - 0.6 A

2 - 3 W

 

Elbow

250 - 400 mA

1.25 - 2 W

N / A

Wrist

200 - 300 mA

1 - 1.5 W

✅

1 central rotator

300 - 500 mA

1.5 - 2.5 W

✅

Shoulder horizontal rotation Yaw (Z-axis)

200 - 400 mA

1 - 2 W

✅

Shoulder vertical rotation Pitch (X-axis)

Unreliable numbers reach 2 -3 A

Unreliable numbers reach 10 - 15 W

❌

Total for 1 arm

0.95 - 1.6 A + N / A

4.75 - 8 W + N / A

 

Total for one arm pib (worst case scenario all joints working)

2.15 - 3.4 A + N / A

10.75 - 17 W + N / A

 

Total for full arm pib (worst case scenario all joints working)

3.65 - 5.8 A + N / A

18.25 - 30 W + N / A

 

Results and Observations

  • Camera power break happening at maker fair 2023 happened because of 1 ampere deficit when Raspberry Pi is directly powering camera and LCD screen. Thus LCD screen should have its own power supply, which is also recommended in the official manual for the LCD screen.

  • Shoulder current is not very safe and while it's very possible in all applications to power raspberry pie from main power source. In order to save more current so that shoulder can work raspberry pi should be connected to its own power supply

  • Having a more powerful main power supply which can provide more than 10-amperes of current would be recommended to overcome any breaks or buying the raspberry pie power supply separately. However to not change BOM, Rpi can be connected to its own power supply and motion for shoulder should be minimal.

References