Re: Need a bit of design work done

From: Mike Rocket J. Squirrel Elliott (j.michael.elliottAT_at_REMOVETHEOBVIOUSgmailDOT.com)
Date: 03/29/05 

Date: Tue, 29 Mar 2005 10:43:54 -0800

On 3/29/2005 3:08 AM Robert Baer wrote:

> Mike Rocket J. Squirrel Elliott wrote:
>
>> I'm an analog guy and I need for a bit of logic/adc design work done,
>> will pay. The design is essentially to sample the voltage on the wiper
>> of a potentiometer, and use it to drive one of 48 relays, depending on
>> the wiper voltage. The relays need to be driven in a make-before-break
>> style. I don't want to run any clocks in the product if at all
>> possible. Low-speed stuff. I reckon this is digital design 101 as
>> taught in 1980.
>>
>> Please private mail me for more information if this sounds like
>> no-brainer stuff to you and you have the time and are interested.
>>
>> I'm located in Carlsbad, CA.
>
> How about the wiper drive one of the inputs to N comparitors, the
> other input of each of those N comparitors goes to a desired point on a
> voltage divider:
>
> <--/\/-+-/\/\-+-/\/\-+-...-+-/\/\-->
> | | | |
> v v v v
> C1 C2 C3 ... Cn
>
> If the taps are equally spaced, then set the hysteresis for all of the
> comparitors the same, and wide for "overlap"; each output controls a relay.

Hmmm. I like the way you think! Does anyone make IC's with multiple
window comparators with something like one-pin control of hysteresis . . . ? 

-- 
--
Mike "Rocket J Squirrel" Elliott
71 Type 2: the Wonderbus
84 Westfalia: "Mellow Yellow (The Electrical Banana)"
KG6RCR