Having a dashboard with the absolute ink levels is nice. Done that.
I still wanted to understand the usage over time. Due to my lazy programming I have been sending the data to influxdb since March without even noticing, since this is done with all useful data automatically. I just had to look for the data and display it in grafana.
The black ink is displayed in grey. The magenta ink is exactly the same as the yellow one, therefore hidden behind the yellow line. Looking at the data spanning half a year, I will need to buy new black ink in about a year or so. The printer (Epson ET-2750) is probably going to die sooner than the coloured ink runs out.
Just to confirm what Colin already suspected:
Yes, the SNMP variable OID 1.3.6.1.2.1.43.11.1.1.9.1.1 for the supply level is an Integer value. For my EPSON printer this is in %. From the MIB definitions it could also be mg for toner or ml for ink, but this seems up to the vendor. I did not dig into this much deeper.
I just found the values with the snmpwalk tool and compared them to the web page of the printer itself. As soon as I had four SNMP values matching the web page, I considered my job done.
And moved on to connect the node-red nodes to form a nice dashboard.
I'm not sure if this is a general rule for all canon printers.
There was nothing documented for the Epson printer, I just hit it with the snmpwalk tool and got answers back to my bewilderment.
Maybe it is worth a try.
Just un update from my side on that small home monitoring project:
I placed two panels side by side on one dashboard, one showing the current ink level, and the other showing the usage over time.
This is why I'm such a fan of node-red. With minimal knowledge and some trial and error you can end up with quite nice things to show.
