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• Speech recognition

  Paczkaexpress • 05/29/2019 at 20:00 • 0 comments

  The system is going to be a part of an intelligent home system. In this case, it is required to provide a capability of the interaction with the user. In a standard device of this type, the user needs to use a special IR remote control to communicate with the system. This approach is very unpractical because of two main reasons. The first of them is obvious impractically with is related to the requirements of remembering/carrying the remote control with yourself.  All of us know how easy is to lost TV remote controller. It will be the same in this case. Thus, we decided to implement a speech recognition system. 

  Nowadays, home assistants such as "Google home assistant" or "Alexa" is getting more and more popular, so connection SmartDoor with one of these systems is a good idea. It was decided to initially use the Google system for the speech recognition purpose.    

  Below, we can find an example of how the system recognises the voice commands.

• Mechanical Design

  Paczkaexpress • 05/28/2019 at 22:38 • 0 comments

  CONCEPTUAL DESIGN AND FIRST PROTOTYPE

                  Our conceptual design and first prototype is a proof of concept. This will allow us mainly to develop the software, gain more understanding of the kinematics of the system and an insight how hard it is for a layman to install the product on a door. We will look for weak points of the mechanics, electronics and software and once they are identified, in another iteration, we will address them by redesigning it for the finalised commercially competitive version.

  TECHNICAL DETAILES

  LINEAR MOTOR USED IN CONCEPTUAL DESIGN (Commercially available linear actuator):

  https://www.amazon.co.uk/Walfront-Actuator-Electric-Electroic-Medical/dp/B076QDK5Q5/ref=pd_sbs_79_4/258-4408100-6868735?_encoding=UTF8&pd_rd_i=B076QDK5Q5&pd_rd_r=133f4233-818f-11e9-a129-79ba9ae217da&pd_rd_w=G0ZQi&pd_rd_wg=agdFR&pf_rd_p=18edf98b-139a-41ee-bb40-d725dd59d1d3&pf_rd_r=8YH5N6J85BQM8RDMX612&psc=1&refRID=8YH5N6J85BQM8RDMX612

                  Permanent Magnet DC Motor Drive Voltage: 12V DC

  Maximum Thrust / Pull: 750N

  Standard Stroke: S = 100mm

  Standard Protection Level: IP54

  Speed: 12 mm/s

  OBSTACLES

                  We certainly see obstacles in the mechanical design and in the prototyping of both the conceptual design and the final one. Plastic parts will be SLA 3D printed and therefore the design should be optimized for both manufacturing and for operational loads when components will be in use. For metal parts we plan to use bought-in standard parts.

  FINAL DESIGN WITH MASS PRODUCTION COMPONENTS

                  Our first prototype is meant to be only a proof of concept. The opening time is approx. 10 sec with the commercially available linear actuator, which makes the operation time too long. The reason for that is these linear actuators are designed for slow motion, short stroke but heavy load lifting. To be competitive with our product on the market, we plan to customize the linear mechanism to our application. In order to that the linear actuator will be redesigned with a helical screw-jack mechanism. It would give a much longer stroke for the actuator to enable to place the product further away from the rotational point (door hinges). It would give more leverage and more power for the product and also more space, because doors sometimes can be in corners of a rooms which limits space for the SmartDoor unit if it is too close to the door hinge.

                  The lead-screw nut of the screw-jack would be a maintenance free, self-lubricating, low-friction engineering plastic nut. A gear-set would be designed between the nut and the motor to reduce the speed of the motor and gain more power for twisting the nut. Due to the rotation of the nut in a housing supported by bearings, the non-rotating lead-screw will move linearly. The gear-set will be designed from high performance engineering plastic in order to be injection mouldable and all the covers around the product also from plastic, optimized for injection moulding serial production.

                  We also plan to design an extra coupling system into the product which can disengage the motor from the gear-set. The benefit of that would be to be able to open the door manually any time it is needed. Additional settings could also be instantly applied through the voice recognition system and tell the software if the door should be manually openable at the moment when instructed so or it should hold on mechanically and it only opens when the software is instructed to...

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