[TowerTalk] BCD relay driver ideas needed

[Roger (K8RI)]

On 5/30/2010 1:04 PM, Roger (K8RI) wrote:
>
> On 5/30/2010 12:27 PM, Pete Smith wrote:
>    
>> I bought an Ameritron RCS-10 antenna switch at Dayton, particularly
>> because of its BCD control protocol.  My thought was to use the BCD band
>> data output from my shack computer, running N1MM Logger, to control the
>> remote relay box in parallel with the manual controller.  But in order
>> to do that, I will need 3 relay drivers to supply the needed current,
>> and presumably, will also need a level shifter because the relays want
>> 12 volts, while my LPT port is 5.
>>
>>
>>      
> I build a number of these for adding streams to Gas and Liquid
> Chromatographs  (GLCs).  The output was BCD, I went to RadioShack picked
> up a single decoder and the number of optoisolators to match the number
> of relays/valves. RS had all the parts, they cost well less than $10
> each and took about 15 to 20 minutes each to build on perf board.
>    
I forgot to mention the optoisolators will drive the 12V relays directly.
The circuit is simple, I think it might be on the back of the decoder's 
package. Just the decoder, some resistors, and the optoisolators. (It 
will need the 12VDC)
The standard decoder decodes 4 lines into 10, so you can drive relays to 
your hearts content.
I don't know if they'd have the parts in stock today, or what they'd cost.

73

Roger (K8RI)
> 73
>
> Roger (K8RI)
>    
>> Has anyone already been down this road, so I won't have to reinvent the
>> wheel?  Is there a way to use traditional PNP transistor source drivers,
>> but with 5 volts on the base and 12 volts on the collector?
>>
>> 73, Pete N4ZR
>>
>> The World Contest Station Database, updated daily at www.conteststations.com
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>>
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>>      
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