The WORKBENCH part 1


#48

tnx… still a bit expensive, this afternoon I’ve tested a BME280 … positive :slight_smile:


#49

fresh start this morning with new code and a new sensor… the BME280

and a new public dashboard address


that silicone kit is for protecting the cheap chinese sma connectors from rusting :rofl:


#50

BME280 seems accurate, also the ‘over 100% humidity’ didn’t occur


(Remko) #51

Payloads is the same as frame counter?


#52

yes :sunglasses:

* changed it

it survived the first night so I leave it now and just let it do its job… for how long it will run on a normal AA battery ?


#53

What are you using as the air purge valve? I’ve found a few but they either come in at about £15 each or I have to buy 1000 from Aliexpress…


#54

drukcompensatie-element-m12-polyamide-lichtgrijs-wiska-evsp-12-1-stuks


#55

here are 4 frames received by TTN gateways from the above BME280 testnode
at what RSSI level its no longer added to the application metadata ?

this is part of the CayenneLPP buffer code from this sensor.
why is the sequence different in the metadata ? 3 4 2 1

p-meta sequence


(Jac Kersing) #56

RSSI does not determine whether data is included. Packet being from gateway received within deduplication timeout is what matters. Packets received after the timeout are discarded as duplicates.


#57

thnx Jac.

and what determines this ’ deduplication timeout '
… a lot of packets from that specific GW, is that possible, a ‘slow’ responding GW with a good rf signal ?

now I understand the following (a little bit) better :

during testing of this node firmware, I had one day my own gateway on, OTAA joining worked fine and when I switched my gateway off the packets were seen by 3 other gateways (sometimes only one)

next day, I had my gateway still off, I started the node again… no OTAA possible but join request visible in application ??
switched my gateway on, re started the node, no problem joining, switched off my gateway…

e voila… packets are seen by 3 gateways.
my conclusion sofar… always start your node close to a gateway :sunglasses:


(Jac Kersing) #58

The back-end. After the first gateway forwards the packet to the back-end it waits for a certain amount of time to allow gateways with slow(er) connections to deliver the same packet. After that time it forwards the packet to the application.

The only thing I can think of is the gateway that received the OTAA request could not respond due to airtime restrictions or may-be it had to drop the response packet because it arrived too late at the gateway (after the transmission slot).


#59

I will try duplicate this again and take some snapshots … this happend several times, so when the receiving gateway/connection is slow… it can drop the back-end join packet and/or the node doesn’t receive the join packets in time… creating the same status… then after several tries you then get the famous 'no_free_channel

’ to allow gateways with slow(er) connections to deliver the same packet. ’

why … isn’t the first packet received the fastest (for joining) and can the backend respond directly to that GW so a bigger chance for a successfull join ?


(Jac Kersing) #60

The first gateway may have the fastest internet connection but not the best RF path to the node.


#62

I wonder, a metallic temp/humidity sensor enclosure 'will that hold the temperature inside longer then a plastic enclosure ?


#63

Looking at your workbench I expect an answer by tomorrow :smile:


#64

next step … how to handle sensor data > learn :sunglasses:


(Reini Cologne) #65

Were did you buy this antenna?


#66

Rocket Scream from Malaysia, asked me to test their new 1.5 v low power node in Dutch climate.
I am curious so I agreed, also to write a review about it for TTN (new idea… reviewing LoRaWAN hardware).

The modules arrived with that 5 dbi antenna… I will ask him if they are for sale separate.
They did some research on small antennas


#67

finishing the coffee spy node :sunglasses:

I listened to the tips from mrme earlier in this topic and bought some thermal fuses

  • special timesaver tip : check the thermal fuse before glueing it to the ac-dc converter :confounded:
    I realise now that I break it during soldering… it was a 65°C fuse :blush:

ok took the broken fuse out and just for this proof of concept I don’t put another one back… we have dc now


#68