tnx kees
actualy I’m working on the PIR at the moment
I had ordered some new PIR’s with a very short (1.8 sec) delaytime.
That’s the time the output stays 'one after movement detection.
The signal wakes up the 32U4 (leonardo) processor and trigger an LoRaWAN alarm signal.
This very low current type has no adjustable time but you can order them between 1.8 sec and 1 hour delaytime.
Nice, now the processor can go to sleep faster, in the code I can set a counter or timer to prevent sending constant alarmsignals when a burglar is walking in the room. And, if necessary I can count people
Just curious (and probably too lazy to scan posts, sorry!) but including or excluding the 20uA of the PIR, what sort of quiescent current do you see with the 32U4 based node (sleeping)? Similar project scheduled for my workbench but likely design to be sealed for life for harsh in the wild deployment so ultimate node life == battery life. Still not sure which MCU I will start with.
the 32U4 is not the most energy efficient processor … and this usb node ‘thing’ has also a rn2483A / ams117 3v3 / dual level shifter so this is not designed for extreme low power (usb stick)
just for fun , it should run TTN UNO code to.
Thanks again @BoRRoZ! That looks like a very interesting module.
We are heading towards proprietary and cheap super low power solutions now. Bumps the regulatory/CE questions from that other thread up the priorities a bit… adds to the end of a very long list!
I went to the shopping mall to buy some glue… and came back with a pir home alarmsystem with 2 remote controls for 8 euro
is there room for an arduino+rn2483 ??? … lets take it apart
there’s not alot of room inside, but he the thing works for the price of an empty enclosure.
interesting is that it uses the same chip BS00001 as all the other china PIR’s
If you take out the electronics there is room for your own pir loralarm … thing is not waterproof
maybe a TINY LoRa inside so you can still make use of the remotes leaving the original pcb ?
3v3 ‘power’ unit with LIR 2450 - its also very easy to make your own charger for this type of LI-ION battery.
when charged connect it to this dc/dc converter which gives you a constant 3v3 output for your mini node
true … now I think about it, there’s a problem because I wanted to read the operating voltage internally but that’s stupid , its always 3v3 because of the dc/dc board.
my idea was to free a pin, like mentioned in the 85 topic, and use that for a PIR so I can switch the use case : PIR or TEMP
have to think a bit now because you may drain these coin cells to ca 3v, drain more and you damage them.
so we have no pins left …how to detect ?
yes sure… I can build it with any processor or RF module, but I was inspired by the ATtiny85 topic and I looked and found everything in my workplace that I thought I need to ’ quickly ’ build a small node…
btw the board you mentioned needs a levelshifter with the rfm95
maybe found a solution … a separate little protection board between the LIR2450 and DC/DC converter
this one has a 2.75V cutoff but maybe you can tweak that a bit by changing a resistor
update small lithium protection boards arrived… have to test the cut off voltage first
yes that’s the same idea, but be carefull, these little protection boards are specific designed for 18650 batteries and they have different characteristics then that LIR2450
I tested a few in the past … if they say 'cutoff voltage = 2.75v ’ don’t believe them … test it first and don’t be amazed when the protection kicks in @ 2.35v ’ … or never
testing TTN node with RN2483 firmware 1.0.1
loaded with the basic sketch
Rx = 3.8 mA
Tx = 14.5 mA
first conclusion … don’t leave the basic sketch in the node with the batteries
I will have a closer look at the ‘sleeping’ code … and ask @Charles and @rocketscream , the low power specialists, for advice how (and if possible) to improve this TTN device
now I will upgrade the RN2483 firmware and test again :
because of the dc/dc board.
