Laptop needs to control external device, on/off maybe proportional on to
off. Only laptop can be used for this app.

Laptop USB port to external switch box needed.
Switch box to contain mechanical or electronic relay maybe DPDT.

Needs Driver software that I can connect to my software I am writing and
will write for interface.

Currently my software can talk to a serial port but laptops nowadays do
not have serial ports. USB is OK with provided drivers with switch box.

Suggestions for USB to switch box device please. Links would be helpful.

Thank you !

On 23/01/2023 19:35, Exp wrote:
> Laptop needs to control external device, on/off maybe proportional on to
> off.  Only laptop can be used for this app.
>
> Laptop USB port to external switch box needed.
> Switch box to contain mechanical or electronic relay maybe DPDT.
>
> Needs Driver software that I can connect to my software I am writing and
> will write for interface.
>
> Currently my software can talk to a serial port but laptops nowadays do
> not have serial ports.  USB is OK with provided drivers with switch box.
>
> Suggestions for USB to switch box device please.  Links would be helpful.
>
> Thank you !

Google for USB to General Purpose I/O. There's lots of stuff out there
with analog and digital connections which can be controlled via USB.
You'd have to add relays if you want to switch a lot of power.

Or, you can get GPIO boards which work with the likes of Raspberry PI's
- which you could network to your laptop.
--
Cheers,
Roger

On 1/23/2023 2:35 PM, Exp wrote:
> Laptop needs to control external device, on/off maybe proportional on to off.  Only laptop can be used for this app.
>
> Laptop USB port to external switch box needed.
> Switch box to contain mechanical or electronic relay maybe DPDT.
>
> Needs Driver software that I can connect to my software I am writing and will write for interface.
>
> Currently my software can talk to a serial port but laptops nowadays do not have serial ports.  USB is OK with provided drivers with switch box.
>
> Suggestions for USB to switch box device please.  Links would be helpful.
>
> Thank you !

There are various kits with FT245 on them. One kit, only has DC signals
for control purposes. But such a device is more likely to be in stock.

This kit happens to have relays for mains voltages. But the packaging
is "hobby quality" and not "consumer quality". You don't get an outlet
board ready to take appliance line cords using this product. You would
need to know what line and neutral are, and safety ground, and interrupt
the correct signal with the relay, for power control. The line cord you
connect to the wall, the plug must be keyed correctly so line goes onto
the right wire colour and so on. This particular product might be SPST.
Or SPDT (single pole double throw, for normally on or normally off wiring).

http://denkovi.com/productv/107/usb-four-4-relay-output-module-board-for-home-automation.html

You would then need to collect some mains level outlets, fasten
them securely to a wooden board used as a substrate and so on.
Fusing might be a good idea. The fusing is to stop fires, and
the device kit itself could still be ruined, even with a fuse in
series.

The FT245 has drivers from the manufacturer (FTDI), and supports various
bit-banging interfaces. The chip has eight outputs, but could be
used to do fake JTAG or the like. Presumably when you buy one
of these relay kits, they tell you which subset of the driver
to use, to control it.

Paul