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Zetalink Technology provides a variety of electronic engineering services for the design of new products. We specialise in small embedded microcomputer products for battery-operated products, signalling systems, voice communications, etc.
We have extensive experience in low-voltage wired signalling systems such as hospital nurse or doctor calling systems, fire alarms, security systems, industrial production monitoring, warehouse signalling, large display panels, etc.
We can take your project from concept, refinement to production readiness, including circuit design, embedded microcomputer firmware development, printed circuit board design, prototype construction and testing, development of materials procurement lists (bills of materials), and production assembly documentation, such as colour assembly documents for manual assembly operations, or location lists for automated assembly equipment. We have capability to build prototypes using surface mount technology (SMT).We have experience with Freescale (Motorola) MC68HC05 and MC68HC08 families, Microchip PIC, Zilog eZ80, Atmel AVR and Texas Instruments MSP430, working in assembler, Forth or C. We have written PC-based application programs to support and test these products using Visual Basic and C++.
Due to our offshore location, we provide these services at very competitive rates, often for considerably less than outsourcing firms located in expensive labour areas. The accessibility of communications via the Internet has allows us to work closely with our customers even if located halfway around the planet. We have provided design engineering services to firms in the USA, Germany and Australia.Examples of various products developed by Zetalink for clients
In several different nurse-call systems, we have produced designs for all of the various wired call and signal stations placed in patient rooms, toilet and bath areas, exam rooms and other staff areas. Many of these stations use embedded microcontrollers that communicate over a LAN network with a standard personal computer that is equipped with special software to handle the task of running the network, processing calls, notifying staff, etc.
The above photo shows one type of interface that connects between the Nurse Master Station and its PC, with a telephone line, and to the nurse-call network. It converts RS232 to RS485 full duplex, with galvanic isolation according to regulations under UL1069. Data and several audio intercom channels are handled by this assembly.
Rooms each have their own centralised control point that monitors numerous patient call switches, staff presence switches and emergency pullcord stations (as in the shower and toilet areas). In this case up to four patient beds can be handled, but if fewer beds are used, extra inputs can be assigned to alternate functions that are often required in private patient rooms.
This photo (above) shows one such room control point. The five lamp sockets that run down the middle from top to bottom receive different coloured lamps that each have particular signal meanings. A translucent plastic cover is added to this unit to diffuse the lamp illumination. This design has been in volume production for eight years, and is installed in many large hospitals in USA, Canada, and Singapore.
The above photo is an example of a simple call station that is connected to the central patient room control point as shown in the previous photo. This station is used to call nursing staff if a patient needs help. The red-tassle call cord would normally reach almost to the floor. A reset button (removed in this photo) is used by the nursing staff to clear the call.
Another simple call station, used where voice intercom communications is not required, is shown below. It accepts a plug-in patient button pendant which is pressed to make a call for nursing assistance. It is designed for one or two beds (this one is a single bed version).
These are examples of complete hospital signalling systems that Zetalink has developed for one client. These designs were supported for many years after the design was completed in that they often required modifications to handle special call requirements and new features that customers demanded.
A somewhat similar integrated system for health care clinics was developed for the same client. In large clinics patients arrive and are assigned one of several doctors on duty. They then are placed in a waiting queue, and when an exam room becomes available, they are then moved into this room. The patient then is normally visited by a nurse to collect vital data, and then waits his/her turn for the doctor to enter. When completed the patient exits the room and the room is marked to be prepared (cleaned) so that it is ready for the next patient. Thus the status of the examination room undergoes a cycle with a number of phases (empty, new patient, vital signs being taken, patient awaiting doctor, doctor present, patient leaves and room is cleaned). Lights above the doorway show, with colours, the status of the room. These are controlled by a microcontroller room monitor.
The room status is marked on a simple call station. The cycle from room empty to the clean-up step is changed by merely pressing the ROOM button on the room status station (photo below). Some steps require that the button is pressed twice to guard against patient mischief. Additional buttons are present to call a nurse and to get additional assistance in the event of an emergency.
A central annunciator (below) can show the status of a group of rooms or a group of doctor's queues with the number of patients waiting in each queue.
In this photo the faceplate (front panel), with room for markings, is not attached. There are 90 LEDs and these are controlled by a microcontroller on a PCB attached to the rear (see below). This module receives commands over the network for displaying different LEDs in different flashing sequences and other combinations. An audio beep tone can also be activated from a remote location.
Another module for the clinic status system is this module (below) for handling patient entries into the doctor queues. This connects to a button patient entry station (not shown).
To properly manage the development of such complex networked devices, it is necessary to actually build a small network and operate the various devices together just as they will be used in actual installed systems. The panel shown below was used for overall system evaluation and debugging during the design and development phase of the clinic status system.
The complete clinic status system, some of whose component parts are shown and described above, was developed from a paper specification to final product installed in a large clinic system at the University of Colorado (USA) over a period of approximately ten months. This is a relatively short time for the development of four separate microcontroller devices, a new proprietary network protocol, and the design and construction of eight different printed circuit boards and their documentation.
(c) Copyright 2003 PT. Zetalink Technology Indonesia
