connecting an 8 position pole switch to I2C with the help of
PCF8574 (8 position) or MCP23017 ( 2 x 8 position)
MCP23017 :
PCF8574 :
my virtual design is almost done… just a couple of weeks more
So I am looking for a small board to battery-power my nodes.
Perhaps this will do:
http://www.icstation.com/lithium-battery-charge-discharge-protection-integration-board-boost-voltage-module-p-8996.html
Previously tried this one:
https://nl.aliexpress.com/item/DC-5V-2-1A-USP-Mobile-Power-Diy-Board-4-2V-Charge-Discharger-boost-battery-protection/32824032545.html
But that has no discharge protection and as a result over-drains the battery.
Any other suggestions?
there exist also 'protected ’ 18650 battery’s, they have a build in protection circuit.
but think of this… when you drain the battery without protection, the MCU brownout will normally shut down the circuit 
also I don’t trust these ‘protection’ circuits from the cheap dc/dc boards… 9 out of 10 don’t work as they advertise.
what you can do is measure (once a day ?) just after Tx the voltage of the battery and send an alarm byte when it’s getting to low.
Most of these ‘protected’ batteries and circuits can let the battery go as low as 2.4V.
I am not convinced its a good idea to let a Lithium battery repeatadly go this low …
hence the battery measurement at regular intervals 
another point I want to make ’ why using rechargable battery’s in low power nodes ’ if a node can run 2 / 3 years on a 3v battery…
these exist too (I used them in different cases) battery holder(s) for 18650 with build-in protection.
I was planning to run a mapper of this with a battery. Let the battery charge overnight and then run it for the best part of a day until the battery dies.
Turns out the amount of parts I would need would for this makes it close to the price of a board with mcu, tx and charger circuit in one.
So another option I would like to explore is to put a mapper/tracker in a boat that would run off the 12V battery but also has a backup. We have a plan to combine a ttn mapper with an anti-theft tracker in a boat and I do not want to fully deplete this guy’s boat battery plus a backup battery would be nice.
this is an interesting charge dc/dc converter to
I remove the red (charging) and green ( full) led and extend wires to a red/green pannel led so that I can see on the case if the battery is full.
module works perfect if you need 5v out
complete dc/dc 3.7 v in / 5 v out rechargable power unit with protection.
just connect to an adapter overnight… led switches from red to green when full
The weather ball 
It has vents at the bottom which lead to a chamber with an SHT-31D sensor in it.
Using the Grasshopper from Tlera Corp which I have fallen in love with + no fuss Arduino library with a great Lorawan stack. I am still considering various mounting options…
Serge
’ green ’ nodes … love it
That is indeed the way to go, thank you for the info.
Very nice but black which very easily (over)heats up in direct sunlight, effecting the temperature measurement.
Hey @BoRRoZ
Where you get the rifle with the seal (top of the pic)? Is it 5,5/2,1?
https://www.thethingsnetwork.org/forum/uploads/default/original/2X/e/e28187eb6769a4069ba0d634f544bc6c8b55f232.jpg
Greets
rifle ?
Thank you.
BigG translatet Buchse = Rifle.
Greets
Hallo all,
for outside work you can better use after the test install with Ty-Raps, some Stainless steel perforation mounting band.
Regards
Johan
you have a link to ?
