Working with Sensacell Modular Interactive Proximity Sensor and Lighting System
The Sensacell system is a revolutionary technology that is ideal for smart architecture, interactive multimedia, retail entertainment, and a host of exciting new applications. Sensacell can turn any surface into a proximity sensitive interface. Sensacell modules can be assembled to form interactive 'Sensor Surfaces' of any size or shape- from a single module to 1000's of square feet. Sensacell sensor technology creates a 3-dimensional sensing zone that project 3-6 inches (75-150 mm) into free spaceright through solid materials- Sensacell modules can turn everyday surfaces into magical experiences. Sensacell applications can range in complexity from simple stand-alone interactive lighting installations requiring nothing more than electrical power, to highly complex interactive systems employing multiple computers to display video and graphics while tracking and analyzing the movements of multiple targets in real time.
Sensing Sensacell modules sense people and objects using capacitive sensing technology; they measure minute changes in electrical capacitance caused by objects moving in the immediate proximity of the sensing electrodes. Large conductive objects (such as the human body) are easily sensed while non-conductive materials can also be detected because they influence the overall capacitance 'seen' by the electrodes through the materials dielectric properties. Placing materials with a high dielectric constant (plastics, glass etc.) over the modules will actually increases the sensing range of the sensors, a very useful effect. Since the sensors detect electric fields, they cannot sense through metal or other conductive materials as these materials block electric fields. This effect can also be useful as a tool to precisely control and modify areas of sensitivity. Small conductive objects placed in close proximity to the sensors can also produce a coupled antenna effect; sensitivity is conveyed to the object by capacitive coupling between the sensor and the object itself, for example, if a metallic soda can is placed near the sensor, touching the top of the can will trigger the sensor. This property can be used to 'sensitize' objects placed on a surface without making a direct electrical connection to the object itself. The Sensacell sensors are intelligent and adaptive; the sensors constantly sample and track the ambient conditions, adjusting to compensate for changes in temperature and humidity. On power-up, the sensors sample the ambient capacitance level detected by the electrodes and use this level as baseline from which subsequent measurements are made, in this way, the sensors can 'learn' to ignore objects that were present on power-up (a sheet of glass covering the modules, for example) while remaining acutely sensitive to new objects entering the sensing zone. When an object is detected, a programmable adaptation timer starts; when this timer expires, the sensors automatically re-calibrate to ignore the sensed object, this ensures that the sensors never get stuck in a triggered state when conditions change. This adaptation process can be remotely triggered or disabled if desired and the period of the timing is adjustable, the sensors are digital and software controlled, their behavior can be customized to suit any application.
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LED Lighting- Visual Feedback Sensacell modules can provide stunning visual feedback in response to user interaction. The on board digital dimmer system is capable of 256 gamma corrected brightness levels providing smooth control over the visual experience. The lighting dimmer system can function independently from the sensors, or the two can be linked internally to create pleasing 'cause and effect' behavior modes. Full color RGB modules can create any color of the rainbow, while monochrome modules produce crisp, bright white light. Fully addressable models like the HSI64-36 and HSI64-36-RGB can be used to display graphics and video as each individual LED can be independently controlled.
Building an Array Scalability Sensacell arrays are infinitely scalable. While each communication network is limited to 255 modules maximum, large contiguous surfaces can be realized by creating multiple isolated networks using special isolation jumpers. Each network should be sized to match the communication bandwidth requirements of the application. Master slave relationship A minimum system consists of a single master module; larger networks consist of one master and multiple slaves. Master modules contain special firmware and hardware; master modules are the communication gateway to the outside world for interface with computers and other devices. Communications Each module in an array becomes an addressable node in a multi-drop, half-duplex RS485 communications network. Auto addressing On power up, the master module initiates the slaves into auto-addressing mode causing the array to automatically self-assign a unique address to each module in the system, based on its physical position in the array. When the array is performing auto-addressing, the communications network will output a stream of data that can be used both to validate the integrity of the array or to re-create a symbolic map of the array's configuration; the host computer can 'learn' the shape of any arbitrary array by interpreting the data emitted during start-up. This data can also be used to quickly pinpoint faults by matching output data to 'Known Good' data templates. Commands Each module in a Sensacell array is an addressable node in a smart communications grid. Commands sent to the master module are routed through the grid to all modules, allowing every aspect of their status and behavior to be controlled by an external computer. Each module in the array can be individually or globally controlled. An individual module can be controlled by sending data packets specifically addressed to it. Global commands can be sent to all modules by sending data packets with the address set to zero. Modes Sensacell modules can operate under the control of an external computer, or as a stand alone interactive system. In autonomous modes, modules perform without need of any external control system, e.g. they light up or change state directly when a sensor is triggered.
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Here are just a few examples of 'autonomous' modes: 1. 2. 3. 4.
Glow Mode- lights smoothly ramp up and down when sensors are triggered On-Off Mode- lights snap on and off, following the state of the sensors instantly. Graffiti Mode- lights toggle on and off, remaining on or off until the next trigger. Paint Mode- each trigger event causes the light brightness to increase slightly.
These various modes can be 'mixed and matched' in any combination for great creative flexibility Once the array is connected to an external computer, the possibilities for complex interactive concepts become limitless. The connection grid Building a Sensacell surface is just a matter of plugging modules together; a Sensacell grid of any size or shape can be quickly installed, tested and placed in operation. Each Sensacell module has four GridPort I/O ports numbered 1 thru 4 located on the rear surface. GridPorts provide redundant power and communication connections to each module in the array, forming the backbone of the self-organizing, fault tolerant system. Sensacell modules must always be connected together at all adjacent edges to form a continuous twodimensional grid. Using the flexible jumpers, the module spacing can be adjusted to any desired pitch and modules can be mounted at angles relative to each other, allowing them to be installed on curved surfaces. Large Sensacell arrays can draw significant electrical current, the modular GridPort jumpers are not suitable to carry current over 2 amperes, power must be supplied to modules via parallel power distribution wiring of sufficient capacity to prevent overloading the jumpers. Consult Sensacell engineering department for assistance in designing power distribution systems. Adjacent Sensacell modules must always be operated as a single synchronous system, attempting to operate two Sensacell modules next to each other without synchronization will result in erratic sensor operation.
Sensing in outdoor applications Sensacell modules can be used in outdoor applications if they are properly protected from the environment, Sensacell modules are electronic devices and should never be directly exposed to water. Modules housed in weatherproof enclosure can sense the exterior environment through any suitable weatherproof material, for example, modules placed inside a store window can readily sense activity on the outside of the window. Effects of rain and standing water Pure water is an excellent insulator, but even trace amounts of contamination render water partially conductive. Urban rainwater can be considered a conductive fluid- rain will trigger the Sensacell sensors. When the exterior surface becomes completely wetted with rainwater, the sheet of water acts as a conductive layer in front of the sensors causing them to trigger and then become de-sensitized when the adaptation timer expires. When the surface dries completely, the sensors will re-adapt and once again function normally. The best choice of surface material in wet environments is one that does not absorb moisture and tends to bead water, rather than forming a continuous sheet. Avoid thick porous materials as they may require extended drying time before normal sensor operation can resume.
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General Installation Considerations: 1 Carefully consider the mechanical mounting conditions. Sensacell modules should be mounted to prevent spurious sensor triggering caused by relative movement between modules and surface materials in close proximity. When designing applications where Sensacell modules are mounted behind large sheets of material, take precautions to avoid the "oil can" effect where mechanical forces on the panel causes the surface to move or bow, causing unintentional triggering of many sensors in the vicinity of the bowing. One solution to this problem is to "float" the modules on the surface material itself, thus preventing any relative movement between the surface and the sensors. 2 Choose surface materials carefully. Many materials contain conductive particles or layers that will inhibit the sensor operation, for example, some paints contain conductive carbon black or aluminum particles, tinted glass, mirrors and 'one way' mirrors can have thin metallic layers that can cause trouble. Always test a sample before committing to a material choice. 3 Use the correct power source. Use a well-regulated power supply of the correct voltage and sufficient current capacity to power the Sensacell array under worst-case, full brightness conditions. 4 Distribute power to the grid properly. Don't overload the jumpers; provide adequate power connections throughout the grid to prevent jumpers from overheating due to excessive current. Use heavy gauge wire appropriate for the current level to distribute the DC power to the modules. 5 Ground the array properly. Connect the negative power supply terminal to a good earth ground to prevent erratic sensor operation. 6 Connect the modules together properly. When installing, be sure that each jumper connector 'clicks' into place so it cannot accidentally come loose. Be sure every position requiring a jumper is populated with one. 7 Orient the modules correctly. Pay close attention to the module orientation during installation to be sure they are all oriented in the same direction. 8 Avoid accidental short-circuits. Don't allow metal objects, screws or loose wires to contact the electronic circuitry on the modules. 9 Protect the modules from water. Seal cracks and joints adequately, provide drip edges to channel leaks away from modules, use drip-loops in wiring to prevent water from following wiring. 10 Prevent module overheating. Provide adequate ventilation to prevent module overheating. 11 Avoid strong high frequency electric fields. Keep the modules well away from devices that generate strong high-frequency electric fields such as compact fluorescent lamps, HMI Lamps, etc. These devices can cause erratic sensor operation if they are too close to the sensors. (less than 2 feet away) Sources of interference can be shielded with grounded metal foil or screening if required. P4 Working with Sensacell REV 2.0 12- 2 8 - 0 8
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Always feel free to discuss your ideas, gripes and concerns with Sensacell; your feedback is a vital part of our ongoing product development process. We welcome challenging application problems, we will work with you to help realize new ways of using Sensacell products, and we will often help develop custom hardware and software to get a new idea off the ground.
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www.sensacell.com / 718-782-8696