MTouch: An Automatic Fault Detection System for Desktop FFF 3D Printers Using a Contact Sensor

Desktop fused filament fabrication (FFF) 3D printers have been growing in popularity among hobbyist and professional users as a prototyping and low-volume manufacturing tool. One issue these printers face is the inability to determine when a defect has occurred rendering the print unusable. Several techniques have been proposed to detect such defects but many of these approaches are tailored to one specific fault (e.g., filament runout/jam), use expensive hardware such as laser distance sensors, and/or use machine vision algorithms which are sensitive to ambient conditions, and hence can be unreliable. This paper proposes a versatile, reliable, and low-cost system, named MTouch, to detect millimeter-scale defects that tend to make prints unusable. At the core of MTouch is an actuated contact probe designed using a low-power solenoid, magnet, and hall effect sensor. This sensor is used to check for the presence, or absence, of the printed object at specific locations. The MTouch probe demonstrated 100% reliability, which was significantly higher than the 74% reliability achieved using a commercially available contact probe (the BLTouch). Additionally, an algorithm was developed to automatically detect common print failures such as layer shifting, bed separation, and filament runout using the MTouch probe. The algorithm was implemented on a Raspberry Pi mini-computer via an Octoprint plug-in. In head-to-head testing against a commercially available print defect detection system (The Spaghetti Detective), the MTouch was able to detect faults 44% faster on average while only increasing the print time by 8.49%. In addition, MTouch was able to detect faults The Spaghetti Detective was unable to identify such as layer shifting and filament runout/jam.

The development of the earth remote sensing from satellite

Remote sensing activities from satellite are important aspect togain information about earth surface, thus has important significance on military, economic and geology fields. After 1962, the term remote sensing became popular and typically refers to non-intrusive observation of the Earth using electromagnetic waves from a platform some distance away from the object of study. Remote sensing implies a measurement made by some indirect or “remote” means rather than by a contact sensor. Remote sensing platform of satellite serves the sensing by using sensors. There are two types of sensors active and passive sensors. This article reviews about the sensors which are used for remote sensing of earth from satellite. This article analyses the sensors for sensing purpose and for attitude control of the satellite.

Online Measurement of the Elastic Recovery Value of Machined Surface in Milling Titanium Alloy

In the machining of titanium alloy, the elastic recovery of the machined surface will cause strong friction between the tool flank and the workpiece surface, which will result in the tool wear and the poor machined surface. This paper designed a new online measuring system to monitor the elastic recovery behavior of Ti6Al4V alloy in dry milling based on the digital image correlation (DIC). DIC measurement principle were analyzed and the orthogonal milling experiments were carried out under different cutting conditions. Because of the complexity of metal cutting environment such as high temperature and chip splash, and the micro scale of elastic recovery of metal machined surface materials, DIC non-contact sensor was designed to measure the deformation of machined surface materials in titanium alloy milling. The displacement data obtained from the experiment were analyzed, and the calculation method of the elastic recovery value of the machined surface was obtained. The measured data were compared with those in other literature. The focus of this paper is to explore the availability of DIC measuring instrument for measurement of elastic recovery in titanium alloy milling. This method can be extended to the measurement of machining of other difficult machining materials.

Theoretical Formulation/Development of Signal Sampling with an Equal Arc Length Using the Frame Theorem

Non-uniform sampling with equal arc length intervals can be found in shape measurements with contact sensor arrays. In this study, the conditions of non-uniform spatial sampling with an equal arc length interval are derived from two frame theorems. First, for general non-uniform sampling, the condition is that the equal arc length interval of the sensors should be less than 1/4Ω. Second, for strictly increasing sampling, the condition is that the equal arc length interval of the sensors should be less than 1/2Ω. The Ω is the maximum frequency of the detected object. For the latter, if the sampling frequency is more twice than the sampling frequency required, the reconstruction error (RRMSE and MRE) is less than 5%. If the sampling frequency is more than 2.5 times, the reconstruction error is less than 3%. The simulation and the experiment are carried out and the results show that a sensor array with equal arc length interval can reconstruct the detected object with high accuracy.

Trigger-Based Dexterous Operation with Multimodal Sensors for Soft Robotic Hand

This paper focuses on how to improve the operation ability of a soft robotic hand (SRH). A trigger-based dexterous operation (TDO) strategy with multimodal sensors is proposed to perform autonomous choice operations. The multimodal sensors include optical-based fiber curvature sensor (OFCS), gas pressure sensor (GPS), capacitive pressure contact sensor (CPCS), and resistance pressure contact sensor (RPCS). The OFCS embedded in the soft finger and the GPS series connected in the gas channel are used to detect the curvature of the finger. The CPCS attached on the fingertip and the RPCS attached on the palm are employed to detect the touch force. The framework of TDO is divided into sensor detection and action operation. Hardware layer, information acquisition layer, and decision layer form the sensor detection module; action selection layer, actuator drive layer, and hardware layer constitute the action operation module. An autonomous choice decision unit is used to connect the sensor detecting module and action operation module. The experiment results reveal that the TDO algorithm is effective and feasible, and the actions of grasping plastic framework, pinching roller ball pen and screwdriver, and handshake are executed exactly.

Can Radar Remote Life Sensing Technology Help Combat COVID-19?

COVID-19, caused by SARS-CoV-2, is now a global pandemic disease. This outbreak has affected every aspect of life from work, leisure, and interaction with technology. Governments around the world have issued orders for travel bans, social distancing, and lockdown to control the spread of the virus and prevent strain on hospitals. This paper explores potential applications for radar-based non-contact remote respiration sensing technology that may help to combat the COVID-19 pandemic and outlines potential advantages that may also help to reduce the spread of the virus. Based on the state of the art engineering technologies, several emerging applications related to COVID-19 monitoring/or protection will be discussed with their technical implications. These applications include remote breathing rate monitoring, continuous identity authentication, occupancy detection, and hand gesture recognition. The paper also highlights future research directions that must be explored further to bring this innovative non-contact sensor technology into real-world implementation.<br>

Contactless Human Body Temperature Measurement and Sanitization

The design and working of Contactless Human Body Temperature and Sanitization is presented in this study. The system is intended to help prevent the spread of COVID-19 infection and assist in maintaining and/or improving community health and reducing the negative impact of the infection on the economy and society. We have used Proteus Design Suit & Arduino IDE software platform with simulating & programming the product algorithm and we are using Arduino Uno, MLX90614 sensor, Ultrasonic Sensors, IR Sensor , Buzzer and DC motor. The objectives of this work is to have a system consisting two sub-systems, the temperature sensor and the sanitizer sprayer, which is controlled from a common microcontroller and by design, can operate simultaneously. The design and development of the system go through the following methodology: System Specification, Literature Survey, Control System Design, Hardware Prototype Development, Results. Based on data obtained from tests made on the built prototype, a reiteration of the above steps is carried out where the control system (software logic) and parameters are adjusted so that they meet the specified performance for the system. The final test results are recorded and it does the temperature monitoring and on disinfecting the hands as expected. Photos of the Schematic and the prototype model ,and the flowchart on which the Arduino script is developed are shown. The non-contact sensor feature for both the recording of body temperature and the spraying of sanitizer provided by our model precludes the possible viral transmission from using traditional thermometers, readers handheld IR thermometer operators and avoids transmission between person to person.