Circuits & Schematics Interfaces

By combining the responses of AD590 temperature sensor and a HS1101 humidity sensor, you can generate a single TTL-level signal containing information from both sensors (Figure 1). This design uses a 74HC123 monostable multivibrator, IC 1 , to form ...

In some applications of capacitive sensors, the instrument’s front end must be small enough to fit into a narrow space. Figure 1 shows a precision capacitive-sensor interface for such use. The square-wave output from a low-voltage 555 timer, ...

Interfacing two systems that operate at two arbitrary voltages is a challenging problem; there is no guarantee that one side operates at a voltage higher than the other side. Usually, the interface is an open-collector or open-drain type with just ...

A USB port offers a handy source of 5 V power for auxiliary devices. A USB port not only supplies power to a microcontroller and other essential circuitry, but also provides enough extra current head room to charge a small battery or supercapacitor ...

You can use a microcontroller that includes an ADC to design a two-wire-plus-ground keyboard interface. For example, you can use a resistive voltage divider to identify a pressed key (Reference 1). A microcontroller's integrated ADC typically ...

The best way to make midrange, low- to medium-accuracy temperature measurements (considering size, cost, performance, and ease of use) is to use an IC temperature sensor. But most IC temperature sensors are designed for applications where the ...

Perhaps the most effective way to gain board space and increase component density is to minimize wiring on the board. A widely used architecture that allows such miniaturization is the I 2 C bus. Comprising only a bidirectional data line, SDA, and ...

Digital-system designs require you to consider many core voltages. Memory operates at 1.8 V, I 2 C and FPGA devices operate at 3.3 V, microcontrollers operate at 5 V, and charge-coupled-device image sensors operate at 9 to 8 V. Clocks for each ...

The design in Figure 1 is a visible optical link for those who need to see the transmitted data. An isolation figure of more than 5000 V is a bonus. Tests of the system used the COM input of a data-acquisition system, as well as a standard PC's ...

The circuit in Figure 1 derives its power from a USB port and produces 5 and 3.3 V supply rails for portable devices, such as digital cameras, MP3 players, and PDAs. The circuit allows the port to maintain communications while, for example, ...