Re: TI-H: Drive-85

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Re: TI-H: Drive-85


Fun! /:

I suppose there are a few ways you could do it. First though, if you 
write it in BASIC, you'll have to make up and more by writing the driver 
on a Microcontroler AND include a TI-Protocol translater that will 
understand the get/send var routines, (which aren't the best on the 
TI-85. I recomend ASM. Also, there are two ways to go about doing the 
work. You could use direct buss access (connect data and address wires 
to the calc, using the TI-85 schematic on my page as a guide

http://www.geocities.com/SiliconValley/Lakes/5081/Richfiles.html

You would need to find some addresses that are not reserved for anything 
and come up with either a port or memory mapped I/O scheme for 
connecting your external hardware. The second option is the "normal" 
way, to conect stuff via the link port. You'll need to use a shift 
register (probably) to get individual paralel I/O lines or you can use 
an I2C 8-bit paralel interface chip. If you want variable speed, go with 
the I2C (simpler circuit). Anyway, whichever you choose, you'll need 
convert the signals to a higher voltage/curent to drive motors. You can 
use relays to control the direction of the motors, and I have book that 
shows how to make motor drives for robots. one system uses transistors 
and relays to drive 2 motors at various speeds. It's a simple concept, 
but the circuit is a little bit large. most of the designs will work 
with just 8 bit data and only need a single line to access. That can be 
brought high if it's all that's there. If you need sensors, you can also 
connect those. If you'd rather have a stering mechanism, you can either 
use servos (expensive) or a low speed geared motor with a potentiometer 
attached. and A/D converter will allow the calc to check exactly what 
angle it is at.

I'll try to get you the title of the book and the author so you can look 
for it. I'll show you how to do the stuff you can't figure out. (If I 
can figure it out!!! =)

Richard Piotter
richfiles1@hotmail.com

>
>
>Hello.
>
>I'm designing a robocar for the TI-85 to control, and would like to 
know:
>
>Would using a counter and de-multplexer and a 'thingy' be a good idea
>to turn the data coming out of the 85 into movement?
>
>What circuits could I use to turn the signals out of the de-multi into
>motor movement?
>(the 'thingy' mentioned above)
>
>Is writing the control program in BASIC a sound idea?
>
>Thanks. 
>
>Dave Goncalves
>n1xzb@juno.com
>
>p.s.  Did I mention that the 85 was going to be in the driver's seat of
>the car, with
>a face on the LCD if possible.
>
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>


Richard 

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