Re: Automatic Wheelchair Turntable

["Robert L Bass" <robertlbass@xxxxxxxxxxx>]

>> At first I hadn't noticed that this is a scooter rather than a
>> wheelchair.
>> The first thing you should do IMO is find a way to ensure that the chair
>> cannot be shifted into reverse unless it is in the lowest speed mode.
>
> Reverse and forward use different gear ratios.  The unit backs up much
> more
> slowly than it can go forward (thank God!)
>
> It's not going to be easy to hack into the control panel for the scooter.
> If I could somehow automatically sense the surrounding terrain, then I
> could
> figure out some way of determining when a higher speed or an anti-tip
> control could be useful.
>
> At first guess, a ring of ultrasonic sensors like those on remote
> measuring
> devices, could tell me something about the surrounding terrain.  If all
> sensors indicated objects surrounding the chair, then the speed control
> should be set to 2 or 3.   If no nearby objects (like slow-moving
> grandmothers), then speed can be set higher.
>
> ...Any time the door is being opened or closed
> by remote control, set the speed control down.

There's another way to do that.  Rig a simple RF transmitter to send a code
any time the car door opens.  A receiver attached to the scooter drops the
speed down to 1 or 2.  RF transmitters and receivers are cheap.  A timer
could keep him from upping the speed for maybe two or three minutes each
time the door opens.

> In thinking more about this, a front and rear "range" sensor is really all
> I
> need and it might turn out to be a considerable safety addition to force
> the
> scooter into the lower speed settings whenever there are objects in front
> or
> being the scooter.

That should work OK but forget about ultrasonics.  They tend to work
erratically when there's any wind around.

--

Regards,
Robert L Bass

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