Hi Mark, and all
I tested a few of the car reversing sensors two or three years ago, for
possibly fitting to the CALL Smart Wheelchair and there are some comments
below.
In general, I don't think they are suitable for indoor use because they
detect too many things, too far away, to be anything other than annoying.
Outdoors is different - see below.
Other things to consider:
Martin Langner's SCAD unit (Chailey) is excellent but I don't think it's
available as a single product.
The CALL Smart Wheelchair has sonar sensors as an (expensive) option.
Simpler than the SCAD - just detects the obstacle and the smart chair then
stops, reverses, turns etc as required. They are made by HMC in Belgium
(they did the DX DriveAssist, I think),. Compared with the car sensors I
tested they are much more predictable and the detection range can be tuned
down to a very short distance so are less prone to unwanted detection. So
far they seem to be pretty good - contact Roger Dakin at Smile Rehab for
more information. 01635 37550.
Car sensors
PDC 100/200 parking sensor (was sold by CPC, about £40)
Two small sensors plus control unit, +12c supply, LED & audible output,
sensors look similar to the 'Quanan' device still sold by CPC for £79.95.
The main problem with this one was that the minimum detection distance was
too long - claimed to be 40 cm but it seemed to be a lot less in use. Also
the beam width was too wide for e.g. doorways, and it seemed unreliable when
detecting obstacles. One to avoid.
Eyemax PDC-2000 (was £135 from RS - no longer available)
Single sensor, 12v supply, visual/audible output
I fitted this as a trial to a smart chair being driven by a blind lad and
much to my surprise it worked very well. Indoors, it's rubbish because it
detects obstacles and door corners too easily, so he always drives with his
smart chair line follower, but outdoors it's great because it detects
people, trees etc and lets him play games and move with some independence
and safety. Only problem is with long grass when you have to tilt the sensor
upwards to avoid unwanted detection. But when I went to order more, they
were no longer available - pity!
Laserline EPS200 (£150)
Dual sensor, audible output only. This one looked quite good but generated a
pulsed audible output that would be harder to interface to than simple led,
so I never investigated further.
Car reversing aid, CPC £128.54 ('mini 3P car reversing aid')
I didn't look at this because it has a digital display rather than simple
led so again interfacing to it looked like it would be a problem.
Best wishes
Paul
____________________________________________
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email!
____________________________________________
Paul D. Nisbet
Senior Research Fellow
CALL Centre, Faculty of Education
University of Edinburgh
Paterson's Land, Holyrood Road
Edinburgh EH8 8AQ
Tel. 0131 651 6236/5
Fax 0131 651 6234
email [log in to unmask]
http://callcentre.education.ed.ac.uk
-----Original Message-----
From: A discussion list for Assistive Technology professionals.
[mailto:[log in to unmask]]On Behalf Of Hawley Mark (RFF) Medical
Physics
Sent: 18 February 2004 14:54
To: [log in to unmask]
Subject: wheelchair sonar
Dear All
I received this request recently. We could use an ultrasound parking aid
for a car but does anyone know of an AT product?
regards
Mark Hawley
A has contacted me, as her mother is in a Nursing Home and is wheelchair
dependent. Her vision is deteriorating and she is knocking into things. She
asked if I knew of a 'sonar' device which could be attached to the
wheelchair to alert her when she is too near to an object. Are you aware of
such a thing?
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