💬 AM612 Passive Infrared Sensor Breakout Board

[Omemanti]

@nagelc I also use normal interrupts. No problems here. Up to 22uA while sleeping, that's fine by me. (3 AAA will last a long time)

[waspie]

yeah well i got a few nrf51822 which was evidently a big mistake

[Omemanti]

@waspie why?

[waspie]

They don't seem to play well and seems like most or any of you guys messing with NRF5x are preferring nrf52.

I have however figured out one problem. Whenever my nrf51 was sleeping i was seeing 1ma current which is a deal killer. I accidentally discovered that disconnecting the st link and replugging it got sleep current to ~5ua. Something about uploading the program puts it in some state whereby it won't sleep properly.

So, I can get it to sleep all the way down now and I'm starting to understand the psel refsel stuff. And, I can make it trigger on p0.03 (an4 or 5, whatever) but its not particularly reliable. I need to get this section right:

void activateLpComp() {
  NRF_LPCOMP->PSEL=4; // monitor AIN0 (i.e. pin P0.02 on nRF52832 PIR Motion Sensor v607).
  while (!(NRF_LPCOMP->PSEL==4)) {} //wait until confirmed
  NRF_LPCOMP->REFSEL=2;  // choose 1/2 VDD as the reference voltage
  while (!(NRF_LPCOMP->REFSEL==2)) {} //wait until confirmed
  NRF_LPCOMP->ANADETECT=0;  //detect CROSS events on PIR detection pin
  while (NRF_LPCOMP->ANADETECT!=0) {} //wait until confirmed
  NRF_LPCOMP->INTENSET=B1000;  //Enable interrupt for CROSS event
  while (!(((NRF_LPCOMP->INTENSET)&B1000)==B1000)) {} //wait until confirmed
  NRF_LPCOMP->ENABLE=1;  //Enable LPCOMP
  while (!(NRF_LPCOMP->ENABLE==1)) {} //wait until confirmed
  NRF_LPCOMP->TASKS_START=1;  //start the LPCOMP
  while (!(NRF_LPCOMP->EVENTS_READY)) {}  //wait until ready
  
  NVIC_SetPriority(LPCOMP_IRQn, 15);
  NVIC_ClearPendingIRQ(LPCOMP_IRQn);
  NVIC_EnableIRQ(LPCOMP_IRQn);
}```

[waspie]

It's looking more and more like the code is fine and its the sensors i'm using that are the problem.

I got some BM612 (cheaper) from ali supposedly the same as am612 but they don't seem to work right. It's like they trigger once and then never again. Can't find a data sheet for them...

I hooked up a 312 just for kicks and it seems to be working. I doubt I'll deploy any 312s due to what seems to be a VERY narrow range and plus it doesn't match the profile of the round board etc...

Anyway, wanted to say that i think this is all working as its supposed to I just got a bad batch of sensors or they're slightly different in some way

[waspie]

For anyone looking to use @NeverDie 's nrf51 circular board (v9) with this breakout - I'm using the sketch as linked from @Nca78 in this post: https://forum.mysensors.org/topic/6961/nrf5-action/1542
in conjunction with the edit to the file as described in this post:
https://forum.mysensors.org/topic/6961/nrf5-action/1514 (the edit to WInterrupt.c and I'm using version 0.6.0 from sandeep)

with just a few minor edits to the sketch from Nca (setting the pin to 10 (sda marked on the circular board).

14ua idle current btw, working like a charm. so far i'm just using a 2032. Trying to figure out a way to strap a cr2450 or 2477 on the back :)

[nithino]

@waspie Apologies for resurrecting this thread after two years. I have quite a few NRF51822 boards with me. I would like to put it to use. Can you please share your code as following these links did not help me compile the sketch. Too many errors. Thanks in advance.

[gulsimsur]

I grabbed the sketch from the 10 year pir but this seems much more geared to the nrf52

[gulsimsur]

@gulsimsur said in 💬 AM612 Passive Infrared Sensor Breakout Board:

I grabbed the sketch from the 10 year pir but this seems much more geared to the nrf52
i don't understand the whole pin assignment thing well enough to know what the heck i'm doing.

[ejlane]

@gulsimsur Why are there links to surveyzop in your reply?

[MasterCATZ]

Thanks for the breakout board, but would it be too much to ask for a revision that can have potentiometers mounted?
so resistors do not need to be changed when tinkering with 15x settings? either SMD or Through-Hole Trimmer

0-300k None?,0-1M

[MasterCATZ]

Or a 12x DIP switch and a Jumper

Jumper for the shortest and longest Time settings
Then pads for installing the 12 Resistors for Time in Seconds the LED / Relay etc is activated for ?

also, how were you mounting these boards with no screw holes? just something for the lens cover to clip into

[NeverDie]

@MasterCATZ That's a reasonable request. In the future whenever I post a board to openhardware.io, I'll endeavor to include the complete set of KiCAD 6 files needed to make simple changes like this, so then I'm not the bottleneck. However, I did this work, and most of my other work to date, in Diptrace, which AFAIK doesn't allow that kind of easy change by other people.

Meanwhile, if anyone wants to re-do the board and post it with the asked-for change, feel free. Because I don't have that need myself, I won't be doing it, because it involves also spending time finding files in some forgotten archive from 5 years ago in order to resurrect it even before making the change.

In any case, I'm glad that at least some people have found it useful, which is why I posted it in the first place. :-)

[MasterCATZ]

all good at least I can steal your sensor hole placements and can stumble along modding in KiCAD

tho unsure why the board size is smaller when I converted it it seems to trim along where the cover's holes are and not leaving any meat behind

did you come across any other sensors better than this for the price?

[MasterCATZ]

@waspie

https://robu.in/wp-content/uploads/2020/09/Pir-BM612.pdf

planning on switching over to these as well

sensitivity setting and better times

[NeverDie]

@MasterCATZ said in 💬 AM612 Passive Infrared Sensor Breakout Board:

did you come across any other sensors better than this for the price?

I vaguely recollect having since come across a newer aliexpress sensor with an even lower power consumption, but I can't say for sure. If that matters to you, it may be worth checking. It wouldn't surprise me, as there is constant progress, and 5 years is a long time.

[NeverDie]

@MasterCATZ and anyone else: If you come across a comparable PIR sensor at a comparable price but with a meaningfully lower current drain, please do post an update to this thread letting us know what it is. I do recollect there being at least one, but by now there may be even more. I could possibly create a new breakout board for it. As I just recently discovered, for a small board of this size, you can order 30 custom PCBs for under ~$5. The first five PCB's would cost $4, but after that the marginal cost is just pennies each. AFAIK, that kind of discounted pricing for hobbyists didn't exist 5 years ago. Either it's the new normal or else it's a temporary thing because of the pandemic or a grab for market share. Not sure which.

[ejlane]

@NeverDie Seems that JLCPCB has had great pricing for at least the past 3-4 years or so. It's been very consistently low every time I've gone looking. I think that's about as long as I've known about them.

[NeverDie]

A quick, cursory look at digikey, and I see that $5 (quantity: 1) will buy you a pir sensor that consumes only 3ua of current at 1.8v while in passive detection mode: https://www.digikey.com/en/products/detail/excelitas-technologies/PYD-1598-7655/6615456
That seems like pretty good performance to me, especially in such a tiny package. In contrast, the AM612 is 14ua at a cost of around $0.85 each (quantity 10 pricing).

Panasonic PIRs that operate at 2ua are available, but at around $20.

Sparkfun claims their PIR board (with a panasonic sensor in it) draws just 1ua, but their price for it is $33.50: https://www.sparkfun.com/products/17375

So, if price is no obstacle, there's a lot to choose from. However, here's how I look at it: use 2x lithium AA primary batteries to power your project (https://data.energizer.com/pdfs/l91.pdf). That's about 3500mah. Then, ignoring other power drains like wireless communications and self discharge, then with the AM612 (at 14ua current drain), those batteries should last you more than 28 years, which is longer than the 20-year shelf life of the batteries. So, unless I've made a calculation error, 14ua seems good enough to me. I guess the argument for the lower drain PIRs might make sense if you're doing energy harvesting.

[waspie]

for what its worth IIRC i'm getting at least 6 months on the ol' 612 with a CR2450.
Close to two years on a CR123a. So yeah, if I made more I'd design a new board for the new PIR sensors you're finding out there but the 612 even with its higher dropout voltage seems to work fine with even a moderatly sized battery.