Projects

Just a few of our recent product designs are described below.

Four-channel Solenoid Controller

Acting on signals received from opto and mechanical sensors monitoring a conveyer system at speeds up to 600m/min, this unit controls four solenoids. The unit is fully programmable via a user keypad using a simple menu structure indicated on the alphanumeric liquid crystal display. Housed in a rugged, custom-designed case, the unit implements all power conversion and signal interface requirements. A central microcontroller monitors and controls all I/O functions, and the unit generates precision 0-10V and 4-20mA outputs for V-to-P and I-to-P converters.

Environmental Remote Control and Monitoring System

Based on a network of wireless sensors that detect temperature and humidity, this system accurately monitors environmental conditions in domestic, commercial or industrial locations. Operating on the 433MHz ISM band at 10mW, the battery-powered sensor modules transmit data on temperature, humidity and battery condition to a central control unit which communicates with a remote data collection module. The system uses the same 433MHz ISM band to communicate wirelessly with remote power switching units which control up to 3kW of mains power to site equipment. As well as implementing precise measurement of the AC load current, the power switching units also monitor RF signal strength to ensure reliable communication with the central control unit.

Wireless Central Heating Control System

This intelligent heating control system employs several custom-designed wireless sensors to monitor temperature at various points around a domestic or commercial heating installation. Operating on the 868MHz band at 25mW, the battery-power sensors transmit temperature data back to a central unit which uses specialised algorithms to control pumps, valves and other loads around the system.

Fume Extractors

Designed to ensure ‘clean air’ conditions in manufacturing, production and laboratory facilities, these mains-powered units provide filtration to remove harmful solder fumes from the air. Using precision differential pressure measurements to monitor the state of the filters, the units employ adaptive algorithms to control the speed of the fan in order to provide optimal filtering under all conditions. Users can program and monitor the unit’s operation by means of a keypad and LED display. Combining a PIC microcontroller, analogue signal processing and motor control electronics, the design provides an efficient solution at low cost.

Valve Positioner

This unit was designed to control a solenoid actuator in response to a 4-20mA control signal. Being loop-powered, the unit demanded a very low power solution, capable of implementing precise control of the actuator using potentiometer feedback. Employing a central PIC microcontroller, precision analogue sensing circuitry, solenoid drive circuits and a keypad and LCD for user interface, the unit provides a simple and efficient solution for a variety of process control applications.

Impact Sound Generator

One of our more unusual designs, this unit was developed to implement the requirements of EN ISO 140-7:1998 and is essentially an impact sound generator used in the measurement of a building’s sound insulation properties. Consisting of five hammers that drop from a standard height at a constant repetition rate, this battery-powered unit combines a microcontroller, motor control circuitry and optoelectronic sensor feedback. Portable, self-contained, and using a precision hammer mechanism custom-designed by A.D.Developments, the unit can also be activated remotely by means of a simple wireless key fob.

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