Page 169 - Handbook of Electronic Assistive Technology

Chapter 6 • Environmental Control 157

These have been standard features in telecare equipment but only recently becoming
available for some EC controllers.
CONTROLLED APPLIANCES
The end of the chain of control of the ECS is the ‘end appliance’ which the user intends to
control, or at least some of its functions.
Control of some appliances through the EC controller can be achieved directly with-
out the need for intermediate interface units. This occurs when the EC controller is capa-
ble of generating the necessary remote control transmission signals for the appliance.
Conventional examples are the television and other audio-visual media devices with IR
remote handsets, the signals of which can be captured by the circuitry of the EC control-
ler and reproduced. Otherwise, such signals are often available in prestored form as IR
code libraries in universal remote control handsets and are now being incorporated into
some smartphone devices and WiFi hub devices. Increasingly, protocols such as Z-wave
are being adopted.
For appliances where direct control from the EC controller is not possible, specialist EC
appliances have been developed or intermediate specialist EC peripheral interface units
(SPIUs) are used. Both of these options are then capable of receiving the control signals
from the EC controller.
Examples of specialist EC appliances are IR-controlled telephones (Fig. 6-3), which
have been available from a number of the EC suppliers over successive decades. Some
1
have been bespoke products produced by EC manufacturers ; others have been modified
versions of commercially manufactured telephones usually through the addition of an IR
2
receiver and appropriate configuration changes.
An advantage of the former is the potential for including functions of benefit to typical
EC users, which may not be available in commercial telephones, such as the announce-
ment of incoming caller, filtering of incoming calls by phone book entry or generation of
or prerecorded phrases. However, the main feature of importance for an EC-controlled
telephone is the audibility performance for the caller and user when in loudspeaker
(hands-free) mode.
SPIUs are used where it is not possible to control the appliance directly. This applies to
many profiling beds, riser/recliner chairs, nurse call systems, community alarm lifeline
telephones and in some instances door openers, gate openers and other actuator systems.
The SPIU consists primarily of solid-state relays, which are configured as remote control
switches to mimic the operation of the standard handset or connection of the appliance.
In the case of nurse call systems and community alarms, a single relay acting as a switch
is often sufficient. For connection to profiling beds (Fig. 6-4) and chairs, multiple relays
are required, often operated in combination to achieve the desired movement and in con-
junction with a time duration limit applied to restrict the amount of movement of the
appliance for a single selection. This is for the safety of the user with time limits typically

1 http://possum.co.uk/.
2 https://www.csslabs.de/cms/index.php/en/.