Re: TI-H: IR detecter

To: <ti-hardware@lists.ticalc.org>
Subject: Re: TI-H: IR detecter
From: "David Knaack" <dknaack@easen.net>
Date: Wed, 4 Mar 1998 13:28:08 -0600
Reply-To: ti-hardware@lists.ticalc.org


In this case, the beam went across the sidewalk in front of my house.
When tripped, the relay turned on the porch light.
Modifying this for slot car racing would not be difficult, and may or may
not require a delay, depending on how fast the cars are going, and how
often the calc checks the state of the port (assuming its polling, and not
interrupt driven).
A car moving at about 5 ft/sec (pretty fast) would interrupt the beam for
about 35ms.  Can the calc reliably detect that short of a change in the
link port?

DK

>5-10 min!  Why do you want a delay that long?
>
>>>An easier one would be a hex inverter if all you need is motion detect...
>>>
>>
>>True, I needed a 5-10 min. delay from the trigger, so I included the 555.
>>Actually, you don't even need a hex inverter, since all you need is one
>>input, you could either use a transistor and a resistor (NOT gate) or just
>>use it as is, call it a normally closed switch.
>>
>>>
>>>>I have done that.  Not too hard actually.  I used an IR led, an IR
>>>>transistor,
>>>>a 555 chip and a relay (to handle loads larger than the 555 can source).
>>>>A few support components and a power supply, and you're ready to go.
>>>>Are you thinking of linking it to a TI?
>>>>
>>>>DK
>>>
>