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Vic-Rel - recreation of the Vic Relay Cassette, a relay i/o interface

M

y teenage self would have been very excited about this. I was very interested in electronic tinkering but a little afraid of damaging my precious Vic. I believe this is an old product, existing back when the Vic was current. (I'm not sure about this. Tell me if you know more about its origins.) It's now recreated by Tim of Shareware Plus and it even includes a copy of the original manual.

As you can see, the manual suggests that this can be used to switch (and receive input from) various things around the house - this was before the 'smart home' was really a thing, outside of Tomorrow's World and a few electronics enthusiasts. Personally I'm interested in building something robotic, such as a XYZ router or mill. 

I guess that the original ones would have come in a case, like a cartridge, because the device is referred to as a 'cassette' in the manual.  

I've seen a number of Vics that have been used in industrial settings (like this one), sometimes even with the keyboard swopped with a custom control panel.  This makes sense as it would have been a relatively cheap computer which is easy to program and interface with equipment.

It has six relays, each with a pair of connections on that stonky terminal block. Together with two inputs, they correspond with the eight i/o lines on the Vic's user port.  As far as the Vic is concerned, these can each be set by software as inputs or outputs, but this device obviously configures them via hardware as 6 out and 2 in. So the manual suggests that the first thing your program should always do is to poke 37138 with 63 to set the Vic up correctly.

The relays aren't power relays. They take a max of 24v / 10 watts.  It's suggested that you connect power relay(s) if you're switching bigger loads than that. What the relays do is to isolate your Vic completely from the terminal block at the other end. Opto-couplers do the same job for the two inputs. This makes it safe to tinker without fear of damaging your Vic. 

Here is the sample program, quick to type and proves that the thing works, as well as teaching you how to program the device. Yes, it does also work with the Commodore 64, you just have to use different addresses when programming.




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