When design engineers at Magic Labs wanted to develop a new magic wand that could generate a display of lights depending on its movement, they used a dual axis sensor developed by Andover-based MEMSIC to help out.
A ‘conjure wand’, as the new wand is more accurately called, is operated by moving it in a specific sequence of motions, called a spell. If a particular spell is performed properly, the wand then generates an interactive display of lights.
Each display of lights is specific for a particular spell, and, because of the functionality of the MEMSIC sensor, the displays are interactive with the operator’s motion, changing their colour or pattern in a manner dependent on the direction or force of the motion.
‘We needed a very advanced sensor, not the crude mechanical sensors used for motion sensing in other toys,’ said Ken Holt, CEO of Magic Labs.
‘The new Memsic product, because of its sensitivity, can measure the smallest degree of tilt, a big benefit for our product,’ he added.
CA-based Magic Labs initially used another sensor. However, according to Holt, the sensor proved to be too expensive to be used in any wands except prototypes.
‘The entire concept of the magic wand centres on the sensor picking up subtle forces in the wand’s pattern of motions,’ he said.
‘The interpretation of untrained, coarse motions of the human hand is not an easy signal processing task, and it helps considerably to start the process with a sensitive, low noise device that is free of gross non-linearities and stiction.’
‘We compute motion direction vectors down to 1/4G, and we go down to 1/10G for tilt measure when the wand is more stable. The MEMSIC part helps with another key magical feature of the wand: no switches or moving parts. The low power of the accelerometer, and its fast turn-on response, enable the sleep and wake modes to be controlled only by the motion of the wand,’ Holt said.
‘Low power components such as these also translate to magically long battery life,’ he added comically.