3D printing technology can produce complex objects directly from computer aided digital designs. The technology has traditionally been used by large companies to produce fit and form concept prototypes (‘rapid prototyping’) before production. In recent years however there has been a move to adopt the technology as full-scale manufacturing solution. The advent of low-cost, desktop 3D printers such as the RepRap and Fab@Home has meant a wider user base are now able to have access to desktop manufacturing platforms enabling them to produce highly customised products for personal use and sale. This uptake in usage has been coupled with a demand for printing technology and materials able to print functional elements such as electronic sensors. Here we present formulation of a simple conductive thermoplastic composite we term ‘carbomorph’ and demonstrate how it can be used in an unmodified low-cost 3D printer to print electronic sensors able to sense mechanical flexing and capacitance changes. We show how this capability can be used to produce custom sensing devices and user interface devices along with printed objects with embedded sensing capability. This advance in low-cost 3D printing with offer a new paradigm in the 3D printing field with printed sensors and electronics embedded inside 3D printed objects in a single build process without requiring complex or expensive materials incorporating additives such as carbon nanotubes.

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A Simple, Low-Cost Conductive Composite Material for 3D Printing of Electronic Sensors

This review surveys micromachined gyroscope structure and circuitry technology The principle of micromachined gyroscopes is first introduced Then, different kinds of MEMS gyroscope structures, materials and fabrication technologies are illustrated Micromachined gyroscopes are mainly categorized into micromachined vibrating gyroscopes (MVGs), piezoelectric vibrating gyroscopes (PVGs), surface acoustic wave (SAW) gyroscopes, bulk acoustic wave (BAW) gyroscopes, micromachined electrostatically suspended gyroscopes (MESGs), magnetically suspended gyroscopes (MSGs), micro fiber optic gyroscopes (MFOGs), micro fluid gyroscopes (MFGs), micro atom gyroscopes (MAGs), and special micromachined gyroscopes Next, the control electronics of micromachined gyroscopes are analyzed The control circuits are categorized into typical circuitry and special circuitry technologies The typical circuitry technologies include typical analog circuitry and digital circuitry, while the special circuitry consists of sigma delta, mode matching, temperature/quadrature compensation and novel special technologies Finally, the characteristics of various typical gyroscopes and their development tendency are discussed and investigated in detail

The Development of Micromachined Gyroscope Structure and Circuitry Technology

Fixed-wing MAV attitude stability in atmospheric turbulence—Part 2: Investigating biologically-inspired sensors

The attitude control of fixed-wing MAVS in turbulent environments

Fixed-wing MAV attitude stability in atmospheric turbulence, part 1: Suitability of conventional sensors

This paper reports a novel capacitive sandwich accelerometer with an eight-beam-mass structure fabricated by self-stop anisotropic wet etching of (1 0 0) silicon and wafer-level Si–Si bonding. In this structure, eight straight beams symmetrically connect to the corners of the proof mass on both sides. These suspension beams are formed by self-stop anisotropic wet etching of (1 0 0) silicon, without heavy boron doping or Si–Si bonding. Through this beam-fabrication approach, the beam thickness can be well controlled and intrinsic stress in the beams is minimized. Accelerometers with different sensitivities can be easily fabricated by varying the thickness of the beams without making any change to the masks. For a device with 17 µm thick beams, the resonance frequency and the quality factor are 696 Hz and 47, respectively. The accelerometer has a sensitivity of 0.35 V g−1.

https://iopscience.iop.org/article/10.1088/0960-1317/18/7/075005/pdf

A novel capacitive accelerometer with an eight-beam-mass structure by self-stop anisotropic etching of (1 0 0) silicon

A novel electrostatic-driven tuning fork micromachined gyroscope with a bar structure is presented. The gyroscope is fabricated by silicon–glass bonding and deep reactive ion etching (DRIE) technology. The gyroscope's driving and sensing proof masses consist of many movable bars. As the motion of the movable proof masses is parallel to the plane of fixed driving and sensing electrodes on a glass substrate, there is mainly slide film damping in the driving and sensing directions, which enables it to achieve high-quality factors and vacuum-free packaging. The gyroscope can operate at atmospheric pressure by electrostatic driving and capacitive sensing. The performances of the gyroscope are tested and the results show that the resonant frequencies and the quality factors for driving and sensing modes are 2.873 kHz and 2.989 kHz, 804 and 789 at atmospheric pressure, respectively. The scale factor and nonlinearity of the gyroscope are 17.45 mV/°/s and 0.43%, respectively.

http://iopscience.iop.org/article/10.1088/0960-1317/20/1/015025/pdf

Yufang Li

Papers

A novel capacitive accelerometer with an eight-beam-mass structure by self-stop anisotropic etching of (1 0 0) silicon

A novel electrostatic-driven tuning fork micromachined gyroscope with a bar structure operating at atmospheric pressure