Control your littleBits projects with a homemade wireless remote

The littleBits electronic building blocks have Wireless Transmitter and Receiver bits. By using the Wireless Transmitter bit with dimmers, buttons, and toggle switches, you can make a custom handheld wireless remote control. For this article, we made handheld remote controls for littleBits vehicles and an MP3 music player. The littleBits Wireless Transmitter and Receiver bits can be purchased individually, or they can be found in some of the littleBits kits (e.g., the Gizmos & Gadgets kit).

The wireless modules can handle up to three signals. Depending on what you are trying to control, you could mix and match between dimmers, buttons, and toggle switches. If you add some littleBits Proto modules, you could come up with some interesting designs.

Wireless Vehicle and Controller

For the vehicle project, we made two versions: One version uses two littleBits DC Motor modules, and the other uses a generic Arduino car chassis with motors. The littleBits motors worked fine, but we found that some low-cost Arduino-compatible 5V motors ran faster, and they offered a little more flexibility. The generic Arduino car chassis comes as loose parts, so connecting the two motors into your own custom project is no problem.

To begin, we collected the littleBits modules and motors we needed (see the box "Wireless Remote Control Vehicle Parts List") and connected the Power bit to a Fork bit. Next, we used two of the Fork outputs to add Dimmer bits (Figure 1) and then the Wireless Transmitter at the end. By using the Fork, we were able to power both Dimmer bits with one battery. We mounted all the components on a littleBits mounting plate and taped the battery to the back.

Figure 1: Wireless remote for a vehicle (top) with a battery taped under the mounting plate (bottom).

The littleBits motor circuit is quite simple. Again, a battery supplies power to a Fork bit, which this time is connected to two DC motor bits (Figure 2). Just make sure that the wheels are turning in the same direction. Finally, we attached the circuit to a mounting board, with the Motor bits on the bottom, and connected the wheels to the Motor bit hubs (Figure 3).

Figure 2: littleBits motor circuit.

Figure 3: Wireless littleBits remote and vehicle.

The second version of the vehicle used the same setup, except the littleBits DC Motor bits are replaced by two Proto bits and the generic motors that came in the Arduino kit. For the motor circuit, you need to wire the Proto bits to the DC motors. The littleBits Proto module has an input side and an output side, each with three screw connectors for power, signal (input/output), and ground (Figure 4). In this project, you use the output side of the Proto bit.

Figure 4: Wiring a Proto bit.

The DC motors have two connection points. If you connect the ground and signal wires one way, the motor spins in one direction; switch the wires, and the motor spins in the other direction. The middle connector of the Proto bit is the controlled output line, which goes to one of the DC motor connection points; the side of the Proto bit labeled GND connects to the other point (Figure 5). Again, make sure the motors are rotating in the expected direction. To finish, we mounted all the littleBits components onto a mounting plate, which we duct-taped to the Arduino car chassis (Figure 6).

Figure 5: Generic motor circuit.

Figure 6: Arduino car chassis with wireless controller.

The steering would probably be easier with simple on/off toggle switches. We drove the car with dimmer switches as you would with an on/off switch. When you adjust the dimmer switch, the last one-quarter to one-half turn goes from full stop to full running, although you do get a small range of variable speed. Visually, a slide switch would look nicer, but again it's only the last 25 percent of the slider that does anything.

This circuit doesn't support reverse, which would require a motor shield or some transistors to do the wire switching.

Remote Controlled MP3 Player

The MP3 Player project used the following littleBits modules:

• 1x Power bit with battery
• 1x Wireless Receiver
• 1x Dimmer
• 1x Button ($8) [11]
• 1x MP3 Player ($50) [12]
• 1x Synth Speaker ($20) [13]

Starting with the same basic wireless remote design used to control the vehicles, we kept one Dimmer bit to control the volume, but substituted a Button bit for the other Dimmer bit for changing the song (Figure 7). On the MP3 Player bit, the mode switch needs to be set to next, so the remote button is enabled to change songs. Finally, we connected a speaker wire between the MP3 Player and the Speaker bit, and we duct-taped the batteries to the bottom of the mounting plate.

Figure 7: Wireless MP3 player.

The MP3 Player module comes with a microSD card that inserts into the bottom of the bit, so with your tunes on the card, you're ready to dance.