The WORKBENCH part 1

it was my first ABP test for this 32U4/RFM95 china adafruit feather clone, just to see if I didn’t make ‘key’ mistakes
code example is here and here
not much free memory left so what we need is an 'stripped lmic version to gain some memory.
the goal is to send temp and humidity data and we need deepsleep.

regarding the battery voltage (drop) , I didn’t even check that code part/pin … was supprised it measured anything :sunglasses:

one thing I noticed immediate, on first boot with a piece of wire antenna on my desk … the packet was seen by 3 gateways, even the one 13 km away … I expected to see only my GW in the console.
that makes me wonder… is the output of the RFM95 that much better than the RN2483 TTN uno clone I build ?
have to check and learn a lot more.


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when the node is only usb connected you’ll get that meassurement 'drop
with battery connected it works ok


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@BoRRoZ I think that the RFM outputs at 20 dBm by default, while the RN2483 is 14 dBm max to be EU compliant.

Regarding the Si7021, do you have any reference value to compare it ? Does it need any calibration ?

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according the datasheet the humidity sensor has a max 3% error @ 0-80% humidity

to check yourself you can use the saturated salt technique:

on some forums they talk about 6% error (to high) on humidity, all in all not to bad for what you pay.
haven’t checked it myself yet.


today I need a full node tank :rofl:

I having some problems lowering the (sleep) current from this 32U4 / SX1276 ‘feather’


I’ve used

possibly the charging circuit or floating pins or something ?

If I can’t free some more memory or lower the sleepcurrent I forsee that this module is usefull as a on/off detector, like a PIR alarm when you leave your house… triggered it can send a message to your phone (first a lorawan packet) and the battery (1800 mA) I use last max one month

What brand of “flux” is that!!! Looks good … drools!


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decided not to use this module in a battery powered node… so I have a new use case for it :sunglasses:

the coffee spy node - an universal LoRaWAN AC current detector, so I can easily check if my old mother had her morning coffee or switched the television on or off.
it just send one on/off byte to the application and is AC powered.

update 12 oct 2018

I should have patented this idea :sunglasses:



flexible 2.5 mm2 soldered and isolated

and puzzle



hey borroz. do you use the hilink directly or does it need some stabilizer on the output? should some form of fuse be included since it is on 220v? i have some hilinks lying around but never dared using them on any nodes.


Yes I’ll mount a fuse between AC and the HiLINK.


Also a 2 color LED, red on power on (plugged in) and green flashing when it can reach a gateway, green continue when the coffee machine/tv is on and a notification is transmitted.

These HiLinks are very good (tested before) , but I’ve never used them on a node, I’m more concerned about possible noise interference with that hall sensor, test before mounting everything :wink:

up to 200 mA load the voltage and ripple are fine.


Wanted to use them in a nrf setup (mysensors). Some tips on fuses (thermal and slow) in this link

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the coffee spy node project is not abandoned but @ the moment other stuff todo :sunglasses:




328p + RN2483 + Si7021 @ 1.5V :

high - 20mA
low- 50uA


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and some fiddling with different sensors


my own gateway is under reconstruction… but still this node is received by 3 other gateways

seen by 03

but probably I’m in a good location and… this 5 dbi antenna give me the best node results sofar.



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’ HOUSTON … we’ve got a problem ’ after the first night camping outdoors :wink:


how’s that possible ? … a humidity over 100% , is it ME or TTN or CAYENNE or a monday morning Si 7021 sensor


a few hours later ( 5 min interval measurements) and its getting better… we’re not 'under water ’

so my question is to you is what is the best outdoor arduino temp / humidity sensor ??

  • update … there is a sensor problem
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This one I suspect:

This channel is an absolute goldmine for Espressif, ESP, sensor, protocol, Arduino IDE, library and many other related facts and fixes.


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