For reasons relating to its visual appearance, the Trilobite vacuum cleaner was named after an extinct marine arthropod, but the self-guided, roving appliance actually has more in common with a bat, given its ability to navigate with the help of sound.
The Electrolux Group, Stockholm, first displayed a prototype of the Trilobite back in 1997 to gauge market interest. According to Electrolux, the response was “overwhelming,” and the company went ahead with a production version that was recently introduced in Sweden. Export of the product to other countries begins later this year.
The round cleaning device, which is approximately 5-in. high (13 cm) and 14-in. (35 cm) across, can scurry under tables and around obstacles. Powered by nickel-metal-hydride batteries and moving at less than 1 mph, the vacuum begins its task by seeking out the nearest wall, then vacuuming along the perimeter of the room, mapping the room at the same time. Then it starts cleaning in an independent, crossing diagonal pattern, calculating new paths when confronted by obstacles. For down stairways, and similar situations with no natural obstacles, magnetic strips are installed to warn the Trilobite not to proceed further. The vacuum will automatically find and return to its recharging station when its task is complete, or when its battery charge runs low.
The appliance uses four different motors, one for each of its two wheels, one for the roller brush, and one for the blower. Independent suspension for the wheels and a unique roller brush design allow the unit to roll over cords and the edges of throw rugs without getting tangled up. Its dust collector holds 1.2 liter and the vacuum can operate up to 60 min. on a full charge.
In its initial perimeter run, the machine takes the measurement of the room by counting wheel rotations. It then calculates estimated cleaning time. It returns to the recharging station by hugging the nearest wall. The recharging station is identified to the vacuum by means of installed magnetic strips.
The most remarkable trait of the Trilobite, however, is its ability to self-navigate using ultrasonic sensing. In principle, ultrasonic sensors typically work by transmitting bursts of high-frequency sound waves, then measuring the time it takes for an echo to return, then using that figure to calculate the distance to the source of the reflection, the obstacle. As can be seen from the photo (previous page), the Trilobite utilizes a gold-metalized film ultrasound transmitter that belts across the front half perimeter of the unit to provide 180-degree sensing capability in the forward direction.
According to Lars Dahl, project manager, the transmitter generates sound at a frequency of 60 kHz. As the sound waves bounce off walls and obstacles and return back to the device, those echoes are picked up by eight different microphones arranged in two rows, an upper and lower. The angle between each microphone in the same row is 45 [degrees]. The Trilobite’s microprocessor, knowing the exact position and angle of each of its microphones, then combines the different distance measurements to create a physical map of what lies in front of it.
It is this use of multiple sensors that allows the Trilobite to know the difference between a wall and a potted plant and then to choose the appropriate navigational strategy.Seven-segment LED displays provide an economical option for cost-competitive applications such as home appliances, games, POS terminals, answering machines, and exercise equipment. The displays feature evenly lighted segments against a gray background to assure optimal visibility. Components are available in different heights in both single and dual-digit configurations. All versions are available in AlGaAs red, GaP high-efficiency red, GaP green, and GaP yellow. Enter 163
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