Print Monitor Brainstorming

I have a customer that would like a Light/buzzer to indicate when a printer outputs a page. It is for a warehouse setting. The order desk sends an order to the warehouse printer to be picked out for a customer. The pickers have no way of knowing that an order has been sent, so they may go on doing other chores, and an order is then not ready to be picked up.
I thought of a sensor to detect the sheet coming out of the printer, but that seems clunky. Is there a way to monitor the communication line to the printer and subsequently generate a contact closure? (I don't know if it is wireless, USB, or ? )

A quick google search reveals this:
http://www.creativemicrotech.com/pfs16r-printer-ala16r.html

what about monitoring the power draw of the printer. It certainly has to rise quite a bit vs just sitting idle.

I like the idea of putting a power monitor on the printer and watching for it to wake up from slumber, or to heat up the toner cartridge.

I would expect most printers to have a page counter available via SNMP management protocol.

A low-code approach would be to use a Node-Red instance to poll the printer for its page count, then send that to a PLC or even a web-controlled relay sort of thing to turn on an indicator light.

Ken Moore, I like it that a 911 agency came up with a "hey go check the printer something came in" alarm. 30 years ago I was the source of a few police reports in Champaign, mostly the "Someone Is Having Too Much Fun At O'Malleys" sort.

My 2007-era Brother HL2170W printer has an ordinary SNMP object as part of the prtMarkerTable object, called "prtMarkerLifeCount". I sniffed it out using the free (if clunky) SnmpB MIB browser.

It represents, as far as I can tell, the lifetime number of pages printed. On mine it said 3243 when I checked it, then 3244 after printing a test page.

The tool I had closest at hand was a Raspberry Pi running Node-Red, so I installed the SNMP nodes, and set up a Flow that queries that value every 10 seconds, and sets a discrete output = 1 for one second each time the value changes.

The first thing I would change is that the Inject node fires when I download a fresh flow, so I'd have to suppress that. But I think I could also make it check for a new sheet, and then only set the output when new sheets have stopped coming for 10 seconds.

If you connected the Raspberry Pi to a printer-pickup horn or light, you could also wire a Reset button in so that the user shuts off the light by pressing a nearby button. If they don't press that button within a few minutes, the Node-Red instance could escalate to sending them text messages or berating them on Twitter.

jaden said:

Light/buzzer ...warehouse setting.... The pickers...

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Part selection is critical here. Make sure to select a buzzer that's still loud when somebody decides it needs a bit of tape adding to it because the noise is annoying them.

If the color of the priniter output tray is dark color, you can use an optical sensor placed above the tray, linked to a timer relay.

Just my thought is get the signal from where the printer gets its signal to print because what if the printer is out of paper or jambs then there is no notification and the data is just sitting there waiting on the printer. so if you get the notice when the printer does picker could be at printer even if it doesn't print. but they would know they have an order.

I would assume that the warehouse has a WES system, so you would have messages going back and forth between plc and server. Make another message when they send an order down and trigger the plc.

tarik1978 said:

If the color of the priniter output tray is dark color, you can use an optical sensor placed above the tray, linked to a timer relay.

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That's what we had at my last place. The maintenance printer had a retro-reflective sensor aimed at the output tray. Wired to a relay that flashed lights all around the plant. It worked pretty flawlessly for over a decade. Sometimes simplest is best...