[tech] Door Circuitry

[Adrian Chadd]

*laughs* There's a short in the lock?


Adrian

On Mon, Aug 30, 2010, Bob Adamson wrote:
> Well...this could have saved several hours of head scratching...
>
> Door relay is alive again. Fixing the short in the lock and replacing the 
> fuse in the modem fixed it, though it took a bit longer to sort out the  
> power issues. Turns out the solenoid and modem are pretty power hungry,  
> and don't want to work with a wall wart.
>
> For future reference, you send ATH1F over serial to trigger the relay.
>
> Bob
>
> On Sun, 29 Aug 2010, James Andrewartha wrote:
>
>> On Sun, 29 Aug 2010, David Adam wrote:
>>
>>> On Sun, 29 Aug 2010, David Adam wrote:
>>>
>>>> On Sun, 29 Aug 2010, Bob Adamson wrote:
>>>>> Sad news - our door relay has kicked the bucket. Somehow the electronic lock
>>>>> got a short in it, killing the modem (!) that drives the relay. Of course,
>>>>> being UCC, this modem was a complete box of hackery. Adrian and myself are
>>>>> working on a simple circuit to replace it, but haven't had any luck yet.
>>>>>
>>>>> If anyone knows anything about how the old setup worked (particularly the
>>>>> success/failure sensing in the binary) please give me a yell.
>>>>
>>>>> From http://www.ucc.gu.uwa.edu.au/services/door.ucc
>>>>   The door lock is switched using the On-Hook relay of a modem. This
>>>>   provides a cheap, reliable serial interface to the door lock.
>>>>
>>>> You need to send ATD (or possibly ATH) down the serial line to make the
>>>> modem pick up the phone line. The thought occurs that you probably didn't
>>>> know that this afternoon which may have been why you couldn't get it to work
>>>> :-)
>>>
>>> Actually it's A0. I think.
>>
>> strings /usr/sbin/opendoor suggests 'ATH1F' and 'ATH0F'.
>>
>> -- 
>> # TRS-80              trs80(a)ucc.gu.uwa.edu.au #/ "Otherwise Bub here will do \
>> # UCC Wheel Member     http://trs80.ucc.asn.au/ #|  what squirrels do best     |
>> [ "There's nobody getting rich writing          ]|  -- Collect and hide your   |
>> [  software that I know of" -- Bill Gates, 1980 ]\  nuts." -- Acid Reflux #231 /
>>