Although electronics is not really my strong point, I spent some time working through the spec sheets for all the various components in the Modular Music Box in an attempt to work out total power consumption – to give a better idea of the battery mAh rating we’d need and some idea of how long they’d last…

Things have changed since this early list and I’m sure I haven’t taken everything into account – the LVBoost now in the battery pack is probably only running at ~60% efficiency for a start – but here’s my initial working out for the record…
Power Requirements

Battery

• Standard Discharge Current 0.2C5A Max Discharge Current 2.0C5A

1 x LVBoost

• typical Quiescent current .4mA max 1.310mA
• input 3.7v – max output 800mA ??

Animation Turntable – total 72mA – 600mA motor

1 x 3.6V KH39EM2-851 stepper motor – 60rpm – use microstepping?

• 0.6A/phase – 2 phase

1 x white LED

• nominal 20mA max 30mA
• Voltage forward typical 3.3 max 3.8

1 x 120 Ohm resistor

• 42mA

Winder – total 1039mA

• if 10mA less per MV7744 = 10mA x 12 = 120mA
• but actually because of multiplexing – PeakCurrent=(8 x LedCurrent) + MAX72XX-Supply = ~170mA

so adjusted total – 240mA

1 x Arduino Duemilanove clone

• DC Current per I/O Pin – 40mA

1 x rotary encoder

• Rating: 1mA/10VDC
• Push-on Switch Rating: 10mA/5VDC

2 x 74HC595 shift register OR 1 x Max7221

• 74HC595 quiescent supply current min 5.5μA max 160μA
• Max7221Operating Supply Current – 330mA

12 x orange LED MV7744

• DC forward current – 30mA peak forward current – 160mA
• Forward voltage typical 2.1V max 2.8V

12 x 220 Ohm resistors

• 23mA (x 12)

1 x white LED

• nominal 20mA max 30mA
• Voltage forward typical 3.3 max 3.8

1 x 120 Ohm resistor

• 42mA

Sound Module – 72mA

1 x Arduino Mega clone OR 1 x Arduino Duemilanove clone

• DC Current per I/O Pin – 40mA

1 x white LED

• nominal 20mA max 30mA
• Voltage forward typical 3.3 max 3.8

1 x 120 Ohm resistor

• 42mA

2 x AD5206 digital pot

• Positive Supply Current Typ 12μA Max 60μA

1 x MM74C14 Hex Schmitt Trigger

• Output Sink Current 3.6mA

capacitors?

Rotary Sequencer – 1246mA – 600mA motor

⁃if 10mA less per MV7744 = 10mA x 12 = 120mA

• but actually because of multiplexing – PeakCurrent=(8 x LedCurrent) + MAX72XX-Supply = ~170mA

so adjusted total – 727mA

1 x Arduino Mega clone

• DC Current per I/O Pin – 40mA

1 x AF Motor Shield

• ?
• L293D Total Quiescent Supply Current (pin 10) Typ. 16mA Max. 24mA
• L293D Total Quiescent Logic Supply Current (pin 20) Typ. 44mA Max. 64mA

1 x 3.6V KH39EM2-851 stepper motor – 2 rpm

• 0.6A/phase – 2 phase

13 hall effect sensor

• Supply Current 50mA

13 x 3mm Orange LED MV7744

• DC forward current – 30mA peak forward current – 160mA
• Forward voltage typical 2.1V max 2.8V

13 x 220 Ohm resistors

• 23mA (x 12)

I2C Bus

?

1 x LVBoost

• .4mA

1 x Adafruit Breadboard Power Supply

• ?
• MIC2941 regulator has guaranteed 1.25A output

1 x white LED

• nominal 20mA max 30mA
• Voltage forward typical 3.3 max 3.8

1 x 120 Ohm resistor

• 42mA

Total Amperage

1111mA @ 5V = 5.56W

+ 2 x motors at .6A @ 3.7 = 4.44W

(Ah) = Device’s Wattage (W) x Time to run ( Hours) / Battery Voltage (V)

So assuming the Modular Music Box is fully operational for 2 hours per day (and idle/in sleep mode otherwise)

(Ah) = 10 x 2/ 3.7 = 5.4