Tag Archives: Help


Looking for help on a couple of items where Google has failed me..

1. Friedland door/window contact twin-pack DC-55.   I have them running – I have RFLINK talking to them – I understand the codes for door opening  and door closing and another for the internal spring being released (anti-theft) – but there is another signal which occurs occasionally – I’m assuming it is something like “battery ok” – but that suggests another “battery not ok” – but I have NO info on this – anyone?

Status: Still no feedback on this - and Friedland's site has no useful info that I can find.

2. On the RFLINK board I have a little whip aerial – it is 70mm high and has the miniature screw fitting for the board at the other end.  What inexpensive, simple antenna would be SIGNIFINANTLY more sensitive without being directional.  From my outside office I can reach just into the house but only just.

Status - some GREAT feedback here but nothing definitive other than it is looking like a DIPOLE might've been a better bet.

3. Grafana and INFLUXDB.  I have upgraded Influx to 1.2 (see the blog entry if interested) but a problem persists – I have a graph showing several temperature lines – inside and outside stuff – nothing extreme.  I have two of them with duff readings in them – one is minus 400 and the other is +6000.  I cannot figure out how to delete readings outside of a range in InfluxDB (on the Pi) and I cannot seem to get WHERE clauses to work in Grafana.   WHERE value < 100 for example just makes the line disappear.   Anyone know the answers?

Status: Solved!

InfluxDB (I'm on v 1.2) you can only delete readings by time - but you CAN do normal queries which return the time.

The CLI (command line interface) is called "influx" - enter that and you end up in an interface you can get out of with "quit".

While in that interface you will see a prompt >

use x  (where x is the name of the database)

select * from y where value>z

where y is the name of your measurement and z if the value - well, this is what I needed it might be equal to, less than etc etc.

You get a bunch of results with the timestamps.

To delete a value - well, here's an example.

delete from uk_office_temperature where time=1490109437728705735

and that is it - it is that simple - when you know how - NOW I can clean up my database and in fact I'll now add filters on the incoming data to stop this happening again.

Thanks are given in the comments - thanks to all for feedback on these subjects - now those of us who didn't know - do.