NO reed switch - blue LED stops flashing on regaining contact

[kotylo]

smaller.mp4

So, i wanted to install it finally in my mailbox, but found another weird behavior. I have the NO reed switch. So the current will only flow in the presence of the magnet. As i imagine, it should always be active, except when the mailbox slot is slid open to throw some mail (for 1-3 seconds usually, i imagine). Once magnet goes far away, the led starts flashing (booting?), but if i don't give it enough time (10 seconds?) then the magnets are back on place and the flashing stops, the LoRa packet is not sent. Is that expected behavior?

[PricelessToolkit]

The board will wake up only when the reed switch goes from "close to open". Led should not blink.

I hope that the firmware is uploaded and the right Attiny is selected.

1. Check if the "reed switch" can disconnect contact properly (don't use too powerful magnet)
2. Check values of R1 100K, R10 220K and C1 10uF

if all the values are correct then the only thing left is to check the connection between ( LATCH 'Pin8' on Attiny ) and (Q1-Base).

[kotylo]

1.0-1.1V while flashing, then 3.3 while solid LED, LoRa sent.

[PricelessToolkit]

it switches off the trigger circuit mosfet too soon, for that reason Attiny can't boot up for "self" powering. let me think about it, and good night.

[kotylo]

thanks a bunch, good night 🤗

[kotylo]

i was talking to ChatGPT, i know, i know 😆. But it had idea of checking with stable power supply. So i did with 3V power bench. The LED didn't flash once, but dimmed a bit. But it mostly worked, if i gave it time between tries. So the next option was to use another battery. I did that, and the flashing stopped (114 mOhm internal resistance). Dimming too. I didn't think of battery issues before, because:

• [soldered] my 3-year-old 500mA LiPo battery was never used I thought it should work ok because the current consumption is low here. Maybe it's quality of the battery has decreased over time. Charged to 90%.
  • 440 mOhm internal resistance
• [connected via neodymium magnets] my 10 year old (now I know, i should not try to find use of my old laptop 18650s now) LiIon battery also had the same behavior. So as another one. And it was fully charged.
  • 130-150mOhm internal resistance.

I guess check you batteries. Maybe some internal resistance is high or just bad contact, but they still do work in a flashlight. I think the question is resolved then :) and again a "dumb" question from my side, i guess.

[PricelessToolkit]

I also didn't think that this could be due to a dead battery, I already thought it was an LDO problem. I talk to ChatGPT too :)