The Star Wars Force Link toys (£4-8) are a range of 3.75-inch action figures and vehicles that contain an embedded RFID chip, identifying the figure to a wrist-mounted reader. This reader contains all of the sound effects for figures in the range, and a motion sensor chip that can be used to trigger sound effects for battles in space and on the ground. And yes, that does include lightsabers.
But how can we elevate this toy into something much grander, say for cosplay? Well, first we need to take it apart and learn how it works!
Get your screwdrivers, spudgers, and soldering irons ready!
Held together with cross-head machine screws, the plastic chassis of the wrist-mounted reader is the typical firm, yet workable, plastic common to mass-produced toys. The chassis is hinged to create two pieces: one worn at the wrist, and the other resting on the back of the hand. To secure the reader to the player, a Velcro loop is used. The size of the Velcro loop is for very small wrists.
Oh, this is packed with tech! Inside the reader is an NXP 61002 RFID reader which connects to the main board via a cable. The NXP 61002 can be detached from the board, and it can be used independently as a generic RFID reader with a Raspberry Pi, Arduino, or any other board that has an SPI interface. On the main board, there is a ‘blobbed’ chip which prevents reading or access. Inside this chip is a basic motion sensor that detects when the wearer moves their arm around.
The motion sensor will only trigger sound effects when there is a figure in the player’s hand. Coming from that chip are a series of test points which can be soldered to for investigation with the correct equipment. Speaking of test points, there are points for SPI which we used to connect to an Arduino for further hacks!
The electronics also contain a 25Q16CS1G, a flash memory chip which stores the audio files played when a figure is presented to the reader.
To power the reader there is a holder for 3 × AAA batteries, giving us 4.5 V of power, but the power is regulated by a 3.3 V regulator. The battery holder is connected to the circuit board in two places: a single wire connecting the ground (GND, -) terminal, and a much larger mechanical connection for the Vcc (+). This connection can be desoldered with careful application of a desoldering pump and a soldering iron.
Once desoldered, we have access to the underside of the board and to the speaker terminals. Desoldering these terminals and connecting an inline amplifier will boost the audio levels of the voice/sound effects.
But what is inside a figure? Well, after performing some rather brutal surgery on Kylo Ren, we found a single RFID tag with only two exposed connections: C1 and C2, with C1 already connected using what appears to be a capacitor. It is possible that by changing from C1 to C2, other functions can be unlocked, and we leave that to curious hackers to investigate.
There is plenty to hack here! We have an RFID reader that is compatible with many devices. All we need is a little time with a soldering iron and access to a compatible device.
For cosplay, we can remove the plastic chassis, prime and paint it to match our cosplay outfit, or we can integrate the electronics. A screwdriver and soldering iron are all we need to pull the electronics out and add it to a Kylo Ren outfit. In fact, with the other figures in the Force Link range, we can add cool sound effects for most characters.
The RFID chip, which is used to trigger the playback of audio, is tiny, but reasonably tricky to get access to. In fact, we need to destroy the figure to get the chip. But, while this brutal act may rob collectors of a figure, we have access to a simple trigger for cosplay. The chip can be hidden in the fingertip of a glove and requires no power! Just by moving the chip near to the reader, we can trigger audio. Add an amplifier and better speaker, and you can bring a great performance with very little tech.
For cosplay and collectors, this is a fun piece of tech to play with and, because it never sold very well, it can be found for bargain prices, including the Dark Lord of the Sith, Darth Vader! Adding this to an existing Vader cosplay would be awesome, and make you the talk of a ‘con!
Getting Started with RFID
RFID is awesome, and it is all around us! Access cards for government offices, security tags in shops, and medicine containers in hospitals are all places where we can find an RFID chip. In fact, some people have RFID chips embedded inside their bodies, so they can interact with door-locks by touching the door!
To get started in RFID, you can purchase an RFID-RC522 board from eBay or AliExpress for around £5, and there are many examples of how to use the board on the internet. But, if you would like something a little more curated and simple to follow, then the Clever Card Kit from Monk Makes is great!
Retailing for around £15, this kit provides all the equipment needed to use RFID cards with the Raspberry Pi. If you, or the kids, are interested in adding RFID to a project, then this is the kit to start with. Purchase it from UK supplier CPC (part of the Element14 family) via monkmakes.com/cck.