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Bluetooth
Published in Mahbub Hassan, Wireless and Mobile Networking, 2022
Finally, we come to the application profiles. In Bluetooth, each application has a strict set of actions that it is allowed to do. For example, all actions of a headset application are defined in headset profile (HSP). Such strict application profiling is the key to Bluetooth’s success in global and pervasive interoperability. Today we can buy a Bluetooth headset from any airport in the world and it works just fine with any mobile device from any manufacturer in any part of the world. Similarly, we have human interface device (HID) profile to wirelessly connect a range of user input devices, such as mice, keyboards, joysticks, and even game controllers, such as Wii PS3 controllers. Figure 21 illustrates how HID profile is used within the Bluetooth protocol stack for connecting a wireless keyboard to the computer.
Digital Interfaces in Measurement Systems
Published in Robert B. Northrop, Introduction to Instrumentation and Measurements, 2018
Clearly, plugging in and setting up a peripheral USB device is a user-friendly process. However, the setup protocol is complex, as shown earlier. This complexity is necessary to allow hot connection and automatic device ID and initialization. It also allows the host to keep track of the different USB devices that are on the bus and operate them correctly. Included in the host’s Microsoft® USB software are a spectrum of device drivers, including human interface device (HID) drivers. HID drivers are available for such devices as keyboards, mice, game controls, remote controls, and joysticks. As use of the USB is rapidly expanding, makers of various new peripheral devices include driver software with their products.
Designing a Low-Cost ECG Sensor and Monitor: Practical Considerations and Measures
Published in Daniel Tze Huei Lai, Rezaul Begg, Marimuthu Palaniswami, Healthcare Sensor Networks, 2016
Ahsan H. Khandoker, Brian A. Walker
To capture and display the digitized ECG signals sent out from the USB microcontroller interface on a PDA or phone, it is first necessary to determine how a software application can capture such signals. The firmware in the USB interface sends out each sample of the signal 100 times per second via USB and, if necessary, would send out the extra information every 10 s along with the data from the main signal. In the simplest case, a USB client is used and configured as an HID device and connected to a computer running as the USB host. No device drivers on the host computer are necessary for HID devices, and all information from the data retrieved through the USB port can be obtained via what is known as HID descriptor reports. Ready-made code from a third party is available (“A USB HID Component for C#” 2007), which makes things even easier by performing all the queries to the data in the reports so that the only thing the software developer needs to do is to handle events such as usb_OnDataReceived(array memory_buffer), which is obviously triggered every time data are received through the USB port. The signal data are analysed and displayed by the code inside this event procedure using the array which holds the contents of the host computer’s memory buffer at the time the data were received. For example, one statement in the code might be capture_value = memory_buffer.data[1], which would capture the first value of the ECG data. It is quite common to write the code in the C# language using Microsoft Visual Studio, as C# is powerful but simple to use when compared to many other powerful languages such as C++. C# is also relatively easy to learn.
TapSix: A Palm-Worn Glove with a Low-Cost Camera Sensor that Turns a Tactile Surface into a Six-Key Chorded Keyboard by Detection Finger Taps
Published in International Journal of Human–Computer Interaction, 2020
Dongseok Yang, Kanghee Lee, Younggeun Choi
Because our TapSix prototype design has HID profiles in the Bluetooth module, it can be connected to any computing device that is HID compatible. Most current general computing devices such as PCs, notebooks, tablets, and smartphones are HID compatible. As shown in Figure 3, the main components of TapSix are a Raspberry Pi Zero with a Broadcom BCM2385 processor, a low-cost camera sensor (OV5647, Omnibus), and an HID-enabled Bluetooth module (FB155BC, Firmtech). A wide-angle lens with a 160° field of view is used to capture five fingers robustly, a 160° infrared (IR) light-emitting diode (LED) is used to extract clear images of the hand and surface, and a 940-nm filter is attached to the lens to obtain reflected infrared images.