littleBits vs Breadboarding: the number module

A look inside the innards of a module.

August 22, 2014

More than 5 years ago, littleBits began as a way to help designers and those not familiar with electronics, to prototype interactions. Since then, we’ve iterated and redesigned our modules to make some of the trickiest and tedious setups, to work in a snap.

At first glance, many people don’t see the months and months of planning, testing and design that goes into each module.

Here, we’ve broken down what it would take to create a number module if you were to breadboard vs. using littleBits.

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Breadboarding:

Cost:
1 breadboard ​​$3.49
19 resistors​​ $1.52
5 capacitors ​​$0.90
1 opamp​​ $0.38
1 microcontroller​ $3.00
1 7-segment display​ $1.89
1 switch​​ $0.35
10 jumper wires ​$0.80

Total cost:​​ $12.33

Time:
Wiring​​​: 3 hours
Programming: ​​2 days
Debugging: ​​2 days

Total time:​​ about 4 days

littleBits:

Cost:
$24.00

Time:
5s

The number module measures the voltage present on its input connector, then displays that value in one of two modes. In “values” mode, it displays the percent of full scale from 0 to 99, with 5V being full scale, or 99. In “volts” mode, the module displays the voltage at the input.

The input signal is buffered by an opamp (U1), then passed through a single pole RC low pass filter to band limit the signal to around 16Hz. This signal is passed to the Analog-to-Digital Converter (ADC) of an Atmel ATMEGA168 microcontroller (U2). The microcontroller performs digital domain noise reduction, and converts the measured ADC values into display values. These values are translated by the microcontroller firmware into control signals that illuminate the correct segments of the display to represent the desired numbers.

Check out the blog next week where we will break down the light sensor!

Featured Products: Number module
Posted in: Around the Office, R+D