Re: TI-H: Drive-85

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Re: TI-H: Drive-85


For steering, instead of using servos, or low geared dc motors with pots,
you can use small stepper motors.  I also have a book on robots (I doubt
it's the same one) and it thoroughly describes steppers.  Steppers are like
4 motors in one.  If you apply voltage to one input (there are 4)  it will
move one notch and stop.  If you reverse polarity, it will revearse and
stop.  Steppers have built in brakes, you don't have to worry about it
getting pushed out of place.  I can develope a circuit for you to try,
moving no more than 50 degrees either way.  You can get a small stepper
motor for about $5 to $10.

                                                                            
    -Robert Brack

reb@netride.com

-----Original Message-----
From: Richard Piotter <richfiles1@hotmail.com>
To: ti-hardware@lists.ticalc.org <ti-hardware@lists.ticalc.org>
Date: Friday, February 20, 1998 11:23 AM
Subject: 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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