The Power Functions (PF) System

Ah yes. Yet another overview by another internet geek about Power Functions. If you feel you know the whole system already, just skip over this post and check out the Large Lego RC Car. Otherwise, read on to understand how compelling and useful all the PF parts really are. Lego truly gave its Technic fans a gift when they came out with all the parts I'm about to lay out for you. [Side note: Dimensions are in "studs", which is the length of a single Lego connection space]

The PF system consists of batteries, motors, and remote control equipment designed to bring your lego machines to life. They can connect to almost any Lego Technic elements, such as gears, wheels, and levers. Technic is a line of Legos that doesn't look like your average Lego bricks; instead these parts interlock in the form of axles and pinholes. Almost all Power Functions parts have such connections around them as well. You will also notice that the PF system has the color scheme of dark grey, light grey, and orange throughout all its elements.

Let's start with the power sources.

To the right we see the standard, 9 Volt battery box. It houses 6 AA batteries, 3 on each side, and has an orange switch at the top. Sliding the switch to the center position turns it off. Sliding it to the left will turn it on, and sliding it to the right will reverse the circuit. A green LED next to the switch turns on to indicate proper functionality. The grey connection at the top is where other functional elements can be "stacked". For example, you can stack 4 motors on the battery box. When you turn it on, all 4 of them rotate in the same direction. Likewise, receivers, the elements that take in signals from a remote, can also be stacked to allow for more functions coming from a single battery box.

AA Battery Box:
Dimensions: 4x8x11. Amount in my inventory: 5

To the left, we have the recently produced AAA battery box. This compact power source delivers the same amount of voltage but less amperage than the standard battery box. Also, it only has "brick" connections, so parts must be added to connect this to a Technic platform. The orange switch indicates the circuit's direction, and the green button turns it on.

AAA Battery Box:
Dimensions: 4x8x4. Amount in my inventory: 0

Now we see the PF Rechargeable Battery Box. Packed with top-of-the-line features, this thing is famously overpriced at a whopping $50. It is small, much lighter than the other batteries, has a "speed control" dial, and contains lithium polymer cells. The charger is purchased separately, for half the price of the battery. It looks just like the AAA box, but has a charging inlet and a dial instead of a switch, which controls how much power it puts out. Turning the dial in the opposite direction slows down or reverses the circuit. The green button turns the battery on and off, and it starts the battery at the same speed setting that it had before it was turned off. There are 7 speeds, plus 7 more in the opposite direction.

Rechargeable Battery Box:
Dimensions: 4x8x4. Amount in my inventory: 0

Alas, the all powerful XL Motor. This is the largest of all Power Functions motors. It packs quite a bit of torque to any Lego machine, and is commonly used for heavy duty purposes.

XL Motor:
Dimensions: 5x5x6. Amount in my inventory: 3

Now we study the all too common M Motor. This is typically featured in sets that have a single motorized function, such as a dump truck with a functioning bucket. Therefore, it is no surprise that this is the motor used for almost all custom Power Functions builds. It has a little over half the torque of the XL Motor. It also has a 2x6 brick frame on the bottom.

M Motor:
Dimensions: 3x3x6. Amount in my inventory: 12

Behold, the BRAND NEW Lego L Motor. This motor is so new it's not even available for purchase yet. It will be featured for the first time in a remote control rock crawler set, which will be the first RC car with suspension that lego will have ever released.
This motor supposedly has more torque than the M Motor but less than the XL

L Motor:
Dimensions: 3x4x7. Amount in my inventory: 0

Guess what? Another brand new motor. This one's called the Servo Motor and is designed for steering systems in cars, and will likewise also be featured in the new rock crawler. It has its own return-to-center ability that defies heavy torque resistance. However, it does not rotate endlessly. It can only do 90 degrees CW and 90 degrees CCW. When a normal remote activates it, the motor takes the full 90 degree angle. When the button is released, the motor forces itself back to zero degrees. An amazing feature about this motor is that when used with the speed control remote, which ever "speed" you rotate the dial will match the angle of the servo motor. In other words, the remote has 7 motor speeds in both directions, but the Servo Motor has 7 angles in both directions, plus the central position. That makes 15 positions, each 12 degrees apart from one another. Each "click" on the speed dial causes the Servo to rotate 12 degrees. The dial on the Rechargeable Battery Box acts the same way. Also, there is a second axle connection behind the orange one shown in the image.

Servo Motor:
Dimensions: 3x5x7. Amount in my inventory: 0

Say hello to the PF Infrared Remote. This is the handset most commonly used to control PF creations. The levers are not pressure sensitive and so cause motors (and lights) to operate at full power when one of the levers are pushed up or down. The black switches on the sides change the direction of the corresponding motor's circuit, to adjust to the user's convenience. The central orange selector switch has 4 positions, each corresponding to the 4 infrared channels the remote can operate with. If the receiver unit is on the same channel, the remote will control that receiver. Also, the red and blue tick marks above each lever correspond to the red and blue tick marks on the receiver (because both the remote and receiver can control two motors). The remote houses 3 AAA batteries above a 4x8 brick platform.

IR Remote Control:
Dimensions: 6x4x10.5. Amount in my inventory: 4

To right lies the Infrared Speed Remote Control. Instead of vertically moving levers, it uses rotating dials. The black switches and the orange selector switch perform the same functions as the normal remote. The dials can be rotated CW or CCW, likewise giving the motor speeds in both directions. Each time you feel a "click" when rotating the dials, the motor changes its speed by 1 setting. To stop a motor all together, simply push the red button under its control dial. Unfortunately, there comes a point where dialing too fast will cause little to no response from the receiver. This remote is best operated by rotating the dials slowly. Like the normal remote, it houses 3 AAAs.

IR Speed Remote Control:
Dimensions: 4x12x11. Amount in my inventory: 2

Here we have the almighty Infrared Receiver. It has the ability to sense signals from both types of remotes, at a limited range, supposedly 10 meters. After a few experiences I found that the range decreases dramatically in the sun. The selector switch differentiates between the 4 IR channels, and any remote on the same channel controls whatever is attached to that receiver. Even if there is no element attached, a small green LED (next to the orange switch) flickers when a signal is sent to the receiver. Otherwise, this LED remains bright at all times. The receiver only has 2 Technic pinholes but a 4x4 brick platform underneath. [I've tried attaching receivers to other receivers. Nothing happens when you press a control.] An updated version of this thing called the Receiver V2 will be featured in the new rock crawler set. My hope for it was to have more channels, but it simply has better internal parts and allows for 2 L Motors to both run at full power even when one stalls. It looks the same as this one, except the "V2" printed between the pinholes.

IR Receiver:
Dimensions: 4x5x4. Amount in my inventory: 6

What we see now is the "Power Functions Light". I prefer LEDs or Lights. Although not very useful for mechanical purposes, these can really add to the swag of your creation, especially if it's a car. Statistically, 100 of these units can be stacked on a battery box before they start to dim.

Power Functions Light:
Dimensions (for each LED): 0.5x1.5x1.5. Amount in my inventory: 1

Now we go for some mechanical parts. To the left I present the Linear Actuator, a PF part that is not officially sold separately. It converts rotary motion into linear motion with a screw mechanism. It can extend 5 studs from its contracted position. There are a few types of parts that were made to specifically fit around the orange connection, to act as "adapters" for motors or gears. The first versions of these endured some friction; when the Lego Excavator set came out and complaints were reported about the nonfunctional arm, this part was remade to require less torque to extend the cylinder.

Linear Actuator:
Dimensions (while contracted): 2x2.5x11. Amount in my inventory: 6

Last, but certainly not least, we have the Mini Linear Actuator. It does not differ much from the normal actuator in terms of functionality, but it extends only 3 studs from its contacted position. Also, it has a permanent "adapter" on the back of it, the kind which cannot attach to motors directly.

Mini Linear Actuator:
Dimensions (while contracted): 1x3x7.5. Amount in my inventory: 4

Whoops, almost forgot. In case you decide to make a device that requires no wireless connectivity, the handy dandy Control Switch is the way to go. It has the exact same functions as half of an IR Remote Control, but with a cable. The lever does not spring back to the middle, however, when let go. You can there for leave a motor running indefinitely and easily shut it off (this switch is much easier to shift than the sliding switch on the battery box).

Control Switch:
Dimensions: 2x3.5x5. Amount in my inventory: 2

Well there you have it. That's the Lego Power Functions system. Now that you have seen it all (except for the extension chords; I hope you understand how those would work), imagine the possible machines that can be made with these parts. Imagine all the vehicles, robots, and even games that one can build - just by using these small parts!