The color coded modules are divided into four categories. Blue, for power, currently includes three modules—the power module to which you connect the 9 volt battery, a coin battery module, and a USB power module. Pink for “input,” currently includes almost two dozen modules such as push buttons, switches, potentiometers, light sensors, and so on. Orange, for “wire,” includes several wires, branching connectors, and logic gates. Finally, the green “output” components include a little over a dozen modules such as motors, a fan, a buzzer, several kinds of LEDs, and a speaker. An example of a circuit might be the blue power module connected to a pink dimmer (potentiometer) module connected to a green motor module. Switch on the power switch on the power module and the motor spins. The following video is Ayah Bdeir, founder and CEO of littleBits demonstrating how to use the modules.
The circuit designs of littleBits are Open Source hardware consistent with the CERN Open Hardware Licence. You can review the circuits for littleBits on GitHub. To view the circuit designs you may need to download and install CadSoft’s free version of their Eagle PCB design software here, although you can often display a PDF of the circuit by accessing the web page about a particular module by clicking the “Circuit Diagram - PDF” link under “Extra Materials.” For example, you can look at the circuit diagram for the “pulse” module on this web page.
Now here’s the caveat: according to the littleBits FAQ page, “other intellectual property rights such as design elements like fonts, white solder mask with purple silkscreen, logos, as well as the modular connection system (including the connectors and the connector system) are reserved by littleBits Electronics, Inc., and we have a number of issued patents and pending patent applications related to our proprietary magnetic connectors and our system of electrical circuits” (Source). In principle, you could design and build your own littleBits style circuit boards but you might not be able to use the magnetic connectors since they are proprietary. They’re not quite what one would think of as open source hardware. It seems then you would have to by littleBits modules and kits from the littleBits website or one of their distributors. The littleBits Base Kit is listed for $99.00 USD on Amazon as well as the littleBits website as of this writing. To some folks this might seem a little pricey.
The littleBits Base Kit contains the following:
1 Dc Motor
1 Light Sensor
1 Bright Led
1 MotorMate (this is an adapter to connect the motor to a Lego cross axle)
1 Screwdriver (to adjust the sensitivity of the light sensor)
1 Battery + cable
20+ pg. booklet
A simple Circuit
Once I received a reviewer’s sample of the Base Kit, verified all the bits were working, and built a few test circuits, I was somewhat concerned that I might wear out the 9 volt battery that is included with the kit. I decided see if my wall wart adjustable power supply would power up the kit.
It is somewhat difficult to find the specifications on a 9 volt battery, but some sources suggest that a 9 volt battery can provide 200mA (milliamps) and others say 500mA of electric current but you can’t always trust what you find on the internet. According to the schematic for the power bit there is a thermistor installed in the circuit which appears to limit the current to 500mA so, I have 9 volts and 300mA selected on the adjustable power supply.
The first module I tested was the motor with no load on it and the motor did spin up. The next circuit I built included the dimmer bit (potentiometer) and the bar graph bit.
The next three pictures show the circuit switched on and then increasing the power with the dimmer bit.
The website for littleBits has a page for suggesting new modules. Most of the littleBits modules have somewhat complex modules, but sometime this year littleBits should have a mounting board available which, according to the website:
The mounting board allows you to keep your circuit intact and move it around with ease! Hold your circuit upside down, vertically, and carry it from place to place without worrying about it breaking apart. Simply snap together your littleBits circuit and press the feet of your modules into the holes of the mounting board. There are four holes in the corners so you can permanently mount your circuit to any surface, project, or permanent installation.
My suggestion for dreambits would be modules with individual electronic components such as resistors, capacitors, transistors, diodes and so on. This might help students of electronics create circuits with these individual components to learn how each kind of component works. In the case of the diode, for example, one module with the diode mounted in forward bias and another module with the diode reversed to investigate how the diode allows current to flow in only one direction (see my article DC Versus AC about how the diode works).
Another simple module could include a 555 timer like the “pulse” module, but instead of having to adjust the frequency of the pulses by adjusting the trim pot mounted on the circuit board of the pulse module with the little screw driver, let other modules change the resistance of the circuit such as the dimmer module, the slide dimmer module, the bend sensor module, the light sensor module, and so on. The circuit for the module might look something like this:
Where you see the Light Dependent Resistor (LDR) in the circuit, that’s where the external module would go such as the dimmer, bend sensor, light sensor, etc.
littleBits Magnetic Stirrer
In the Base Kit, the motor module comes with an adapter for a Lego cross-axle so you can add motion to a Lego project. There does not seem to be a littleBits adapter for other construction toys such as K’nex or Erector. I decide to see if I could use the motor with Erector set parts and build a simple project and the simplest motorized project for the laboratory I could come up with was a magnetic stirrer. The littleBits motor spins fairly slowly so I attached a 50 tooth contrate gear to the motor module to turn a 12 tooth pinion gear on the axle of the magnetic stirrer. I was able to attach the contrate gear to the littleBits motor axle with a single set screw but keep in mind the diameter of the motor bit axle is smaller than an Erector set axle so you may need to use two set screws to center the axle of the motor module. The following pictures are the magnetic stirrer with the littleBits motor module:
The following is a video of the littleBits motor module drive the Erector set magnetic stirrer:
Neodymium magnets courtesy of Bunting Magnetics:
I managed to keep my laptop limping along so while I'm still able to use it, I'm appending a second project to this article. It is a sample rotator.
Note: The black strap that holds the 50ml centrifuge tube to the axle is a re-sized Velcro cable-tie from a laptop power cable.
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