The PFx Brick is a device which transforms LEGO® creations with awesome new possibilities for lighting and, for the first time, sound!
Frequently Asked Questions
We will be offering the 4 MB version of the PFx Brick as our initial offering in this campaign. This capacity is more than sufficient for most applications. In all of our demo models, we have rarely used more than 50% of the available memory. After the campaign is completed, we will be opening our online store and selling (pre-order) 4 MB, 8 MB and 16 MB PFx Bricks.Last updated:
There are two main reasons why we use the uncompressed WAV format vs. a compressed format such as MP3:
1. Licensing - MP3 decoders require expensive licensing, either in software or hardware form
2. Performance - Decoding MP3 in realtime in firmware would significantly increase our CPU power consumption and reduce battery life. Alternatively, if we use a hardware based MP3 decoder, then this adds another chip that we have to include in the design. Currently, the PFx Brick is very densely packed and it is unlikely we could fit another MP3 decoder chip. Both software or hardware based MP3 decoding would increase the cost due to licensing and additional part count.
The WAV format is uncompressed and therefore has better audio quality compared to a compressed format. Furthermore, because it is uncompressed, the PFx Brick CPU can perform polyphonic mixing, resampling, and other signal processing tasks since it is not burdened with decompressing multiple streams of audio.Last updated:
No. You will have to provide your own LEGO® brand extension wire (either #8871 or #8886) between any of the LEGO® Power Functions™ battery boxes (#88000, #8881, or #8878) and the PFx Brick. The LEGO® extension wire can also be used to power the PFx Brick from a LEGO® 9V Speed Regulator (Bricklink part #2868b).
Note that you can choose to power your PFx Brick via USB instead of using a Power Functions™ battery box. You can use a USB wall adapter, a USB cable to your computer, or a USB battery pack as a PFx Brick USB power source.Last updated:
Yes. After completing this campaign, we will be opening our online store on our website. You will be able to purchase many different additional accessories for your PFx Brick including Light Accessory Boards (LABs), speakers, extension wires, and much more. So if you ordered a M Speaker value package, you will be able to buy an XL speaker from the online store as a separate accessory after the campaign in finished.Last updated:
Not yet! But it will! We have prioritized support for the LEGO® brand Power Functions™ remote controls for obvious reasons; however, we intend to extend this support. Some of the remote controls we are considering are as follows:
- LEGO® brand 9V RC Train remote control (Bricklink part #40529c01)
- Sparkfun IR Remote Control (https://www.sparkfun.com/products/11759)
- Adafruit Mini Remote Control (https://www.adafruit.com/products/389)Last updated:
The software (PFx App) is a desktop based app which communicates with the PFx Brick via USB. Porting this software to a mobile OS would not be useful unless the mobile platform had a physical USB connector and made the USB interface available to Apps. The other alternative is for the PFx App to act as a "broker interface" between the PFx Brick and a mobile app. The mobile app would communicate with the PFx App via a network socket, and the PFx App would relay the mobile app's requests to the PFx Brick via USB. We have considered this possibility; however, unless the PFx Brick is widely in use and enough users ask for the this feature--it likely won't happen. The key thing about the PFx App is that it is not frequently used. Its purpose is for configuring the PFx Brick, but once its done, the PFx Brick stores all of its settings, audio files, etc. and runs standalone. There's no need to connect it again unless you want to change its configuration.Last updated:
We have! Bluetooth 4.2 Low Energy will be installed in every PFx Brick. Based on your feedback, we recognized that we mis-judged its importance. Fortunately, we were already working on Bluetooth support. We reviewed the state of our design, and concluded that we will exclusively produce the PFx Brick with both IR and Bluetooth support.Last updated:
LEGO® introduced the V2 IR receiver because of the serious issue of inrush current resulting from a design change to M Motor. The revised M Motor included a bigger filter capacitor and caused very high inrush current at startup. As a result, it would trip the short-circuit protection in the motor driver chip. LEGO® was forced to introduce the up-rated V2 IR receiver with greater drive current.
We have evaluated 3x different motor driver chips to find one which could reliably tolerate the high inrush current of the revised M Motor. The driver we use is rated to more than 3 A current. In practice, this amount of current is almost never sustained in continuous operation. Most Power Functions motors consume anywhere between 100-600 mA depending on load and applied voltage.
The 3 A rating is only useful for the brief few microseconds where the M Motor capacitor gulps an enormous amount of current until it reaches its full charge. After it reaches its steady state charge, the current drops dramatically to normal current through the motor windings.
The PFx Brick is more than suitable for driving very high motor loads. In summary:
1. It includes dedicated motor driver chips on each channel which are significantly over-rated for the task.
2. It drives the motor channels with a high frequency PWM (pulse width modulation) which results in silent motor operation without the signature "whine" of the IR receiver.
3. We provide an optional "torque compensation" mode which initially drives the motor with a super-low frequency PWM which is randomly modulated. This helps "shake" the motor bearings from their initial static friction and high initial torque.
4. We offer adjustable speed curves for better speed control.
5. You can choose how many speed steps (anywhere from 3 to 100)
6. You can optional invert the polarity of a motor channel (without a separate accessory)
7. You can optionally specify acceleration and deceleration behaviour for each motor channel
The 3 A source current is limited by your power source, which in most cases will be a battery box. However, it is the instantaneous current that is a problem rather than sustained current. The motor driver chip will activate its over-current protection long before the current protection in the battery box. The AA battery box and rechargeable battery box are both capable of delivering bursts of high instantaneous current during the inrush current phase of the M Motor. Therefore, it is still necessary to install the 3 A capable motor driver with a higher threshold for over-current protection.
One final point: Anyone wanting to buy a LEGO® V2 IR reciever, will find that they average $63 USD on Bricklink (as of Apr 1, 2017). Why pay $63 USD for a V2 receiver when a PFx Brick is $65 USD and provides more sophisticated motor control AND gives you an 8 channel lighting Fx controller AND sound Fx AND customization AND USB 2.0, etc...Last updated:
Our campaign funding goal was based on one fundamental number: 1000x PFx Bricks.
We designed the campaign to produce a minimum of 1000 PFx Bricks so that:
1. We cross the threshold for big quantity price discounts on electronic components. It would cost us more to make 800x or 900x PFx Bricks than 1000x!
2. We can amortize the investment of one-time costs such as plastic injection molding and certification over enough units to be economically reasonable
We know that the SBrick campaign yielded approx. 2000x units and the BuWizz campaign around 500x units. Therefore, we made what we thought was a reasonable projection of 1000x units as a compromise. Whether or not our judgement will be validated to achieve this goal of 1000x units has yet to be seen.
The bottom line is that volume manufacturing is expensive. We've itemized costs in acute detail and have been conservative. Many campaigns run into trouble due to inadequate budget preparation; we're confident that we won't be one of them.Last updated:
IR lockout mode allows more than one PFx Brick to respond to IR events on the same Power Functions channel number without interference. It also allows multiple access when a PFx Brick is operated alongside a LEGO® IR receiver.
IR lockout mode can be activated by an IR event of your choice. Once a PFx Brick is in lockout mode, it will ignore all IR messages except for a message which deactivates IR lockout mode.
For example, say we have two PFx Bricks A and B, and both are configured to control motors using channel 1 of a jog-wheel remote. Whenever we use the jog-wheel remote on channel 1, both PFx Brick A and B will control their attached motors. Now, lets say that we configure PFx Brick A to toggle in/out of IR lockout mode whenever the left push button of channel 1 is pressed. We press the left pushbutton, and PFx Brick A will enter IR lockout mode. Now, when we use the jog-wheel, only PFx Brick B will control its attached motors. PFx Brick A will ignore these events. If we press the left pushbutton again, PFx Brick A will leave IR lockout mode. If we operate the jog-wheel again, both PFx Brick A and B will respond and control their motors.
With careful setup of multiple PFx Bricks, you can effectively multiply the number of independently controlled device channels beyond 4. You can even setup a startup action so that the PFx Brick enters IR lockout mode immediately after power up. This way, it will only respond to IR events once it receives a command to leave IR lockout mode. The command or event to change IR lockout mode is almost like a "password" especially if they are configured as unique events for each PFx Brick that is operating in the same location.Last updated:
Yes. You can use either a Power Functions™ 8871 or 8886 extension wire. The dark grey connector connects to the PFx Brick input connector and the light grey connector connects to the 9V battery box or regulator. The PFx Brick will work with one polarity (direction) but not both. Although no damage will occur, the PFx Brick will only be energized when voltage of the correct polarity and at least 5 V DC is applied.Last updated:
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