💬 Multi-Sensor: Temp/Humidity/PIR/ Leak/Magnet/Light/Accel

[NeverDie]

I have an experimental version in the works which uses a micro USB connector instead of the 10-pin connector. The advantage is that it can be connected from the side rather than above, which means the PIR sensor can be snuggled up close to the rest of the Multi-Sensor PCB and then permanently soldered into place:

The result would be an even more compact PIR sensor.

Once there's an OTA bootloader, though, this issue will become moot, and so I think for most people the 10-pin solution will be easier, especially for noobs.

[NeverDie]

@nca78 Which do you think would be the best accelerometer to use? If affixed to a garbage can, for instance, it should be able to detect the trash can being emptied by the garbage truck.

[Nca78]

@NeverDie said in 💬 Multi-Sensor: Temp/Humidity/PIR/ Leak/Magnet/Light/Accel:

@nca78 Which do you think would be the best accelerometer to use? If affixed to a garbage can, for instance, it should be able to detect the trash can being emptied by the garbage truck.

That's a very tough question :D
For low power the best is ADXL362 but it can only be controlled using SPI which is a problem for that specific NRF51 module. And it's not that convenient as low power comes with limited "advanced" capabilities that would be useful for this kind of sensor: tap/double tap detection, free fall detection, ...

I'm making a board with the same nrf51 module and my choice is LIS3DE because it has those advanced functions and can go as low as 2uA, it's very cheap (<1$) and it's small, but I'm only using the chip and not a breakout board. There are LIS3DH breakout boards on AliExpress, it's similar but the boards are big as they map all pins in a row. Only board with less pin is nearly as expensive as some NRF51 + LIS3DE combo so it's not worth buying the breakout.

I will make a version with a LSM303AGR too, it has accelerometer + magnetometer. Magnetometer is power hungry but you can use it only when accelerometer detects some movement, so you know the orientation of the sensor. That way you could easily know the difference between your garbage can being moved around, and it being turned over in the garbage truck. But here again bad news in term of breakout boards, the LSM303 breakout boards available are not the -AGR version, and I'm not sure they can run the accelerometer in a real low power way (LSM303AGR is 3.7uA in lowest power accelerator mode).

There are also some Bosh accelerometer but using more current (6.5uA for BMA255 for example) and same problems with the breakout boards: they are huge.

Sorry, no good answer to your question as there's no compact, low power, i2c compatible breakout board that I know about. If you want to use a breakout board my advice is to go for ADXL362, and if you're out of pins with this nrf51 module you can hardwire the chip select pin to save one.

[Nca78]

@NeverDie you can also measure tilt using an accelerometer (acceleration measured is the gravity in that case) but it's possible only if there is no movement, so I don't think it's usable in a garbage truck processing.

[NeverDie]

I guess it's the land of compromise. By default I'm going with the BMA220, if only because the board is small and the low power mode current drain is 10ua: https://www.aliexpress.com/store/product/DFRobot-BMA220-3-Axis-Triple-Axis-Accelerometer-sensor-2-0-3-6V-I2C-Interface-Tiny-size/1681007_32791058717.html
It's not cheap, but I only need a couple: one for trash can and the other for a curbside recycling bin.

You're right though: maybe all I need is some kind of tilt detector, like maybe a mercury switch of some kind. Perhaps that would be cheaper, and the current drain could be almost nothing.... Thanks!

[Nca78]

@NeverDie said in 💬 Multi-Sensor: Temp/Humidity/PIR/ Leak/Magnet/Light/Accel:

I guess it's the land of compromise. By default I'm going with the BMA220, if only because the board is small and the low power mode current drain is 10ua

At this price buy the small LIS3DH breakout, you'll enjoy the included tilt calculation and a 2uA consumption, 10uA for button cell it too high
https://www.aliexpress.com/item/LIS3DH-Module-Acceleration-Sensor-Module-Evaluation-Board-Development-Board/32285377730.html

Else go for that one it's cheaper and has the nrf51822 onboard
https://www.aliexpress.com/item/Nrf51822-LIS3DH-Bluetooth-Module-CJMCU-8223-Bluetooth-acceleration-module/32821873481.html

[NeverDie]

@Nca78 said in 💬 Multi-Sensor: Temp/Humidity/PIR/ Leak/Magnet/Light/Accel:

https://www.aliexpress.com/item/LIS3DH-Module-Acceleration-Sensor-Module-Evaluation-Board-Development-Board/32285377730.html

Those are both good suggestions. Thinking now though of minimal effort, I may try some cheap ball sensors first:
https://www.aliexpress.com/item/200PCS-LOT-Sensitive-SW-520D-Ball-Switch-Angle-Switch-SW-520D-Tilt-Switch/1967714977.html?ws_ab_test=searchweb0_0,searchweb201602_4_10152_10065_10151_10344_10068_10130_10345_10324_10342_10547_10325_10343_10546_10340_10341_10548_10545_10541_10562_10084_10083_10307_10178_10060_10155_10154_10539_10312_10059_10313_10314_10534_10533_100031_10103_10073_10594_10557_10558_10596_10595_10142_10107,searchweb201603_25,ppcSwitch_4&btsid=110cafb1-1528-4ca9-bf01-4df9ccf33b93&algo_expid=8506dd81-1d5d-4627-9ae5-f3df06594fbb-9&algo_pvid=8506dd81-1d5d-4627-9ae5-f3df06594fbb&rmStoreLevelAB=0
I could stick it in one of the leak detection pinouts of my existing board, so it should be easy. :)

[NeverDie]

Actually, this contraption looks even more promising than the ball switch: https://www.aliexpress.com/item/Vibration-Switch-Shock-Vibration-Sensor-Shaked-Switch-Shaked-Stick-Skates/32686838884.html?ws_ab_test=searchweb0_0,searchweb201602_4_10152_10065_10151_10344_10068_10130_10345_10324_10342_10547_10325_10343_10546_10340_10341_10548_10545_10541_10562_10084_10083_10307_10178_10060_10155_10154_10539_10312_10059_10313_10314_10534_10533_100031_10103_10073_10594_10557_10558_10596_10595_10142_10107,searchweb201603_25,ppcSwitch_4&btsid=8ee4bf46-c3de-4f6a-b23f-32b800aefc7a&algo_expid=d469a8ff-4dce-4442-8590-0e2fdefb1f4b-14&algo_pvid=d469a8ff-4dce-4442-8590-0e2fdefb1f4b&rmStoreLevelAB=0

[NeverDie]

I uploaded new, upgraded demo code. It's tested and works. :)

SUMMARY: The demo sketch runs on MultiSensor Version 7 board with an I2C Si7021 module to transmit temperature, humidity, and battery voltage to a MySensors gateway using MySensors protocols.

[Nca78]

@NeverDie have you seen the comments ? :D

Damn thing works only for the impact of accelerations> 50g. and only in one direction. In life it is not applicable. Shit, shorter.

[NeverDie]

@Nca78 No, I hadn't. Now I'm wishing I had. Good catch! I'll try cancelling my order....

[NeverDie]

Thinking about it more now, I think the ball switch will definitely work if I position it with a vertical orientation, because they invariably fully invert the trash/recycling bin in order to empty it.

[NeverDie]

Here's a node with the Hall sensor installed:

I'll probably be testing it later today.

[NeverDie]

Tested. The Hall sensor works. Basically, if you run this code:

#define HALL_PIN 9
  hwPinMode(HALL_PIN, INPUT);
  while (true) {
    if (digitalRead(HALL_PIN)) {
      digitalWrite(LED_BUILTIN,LOW);
    }
    else {
      digitalWrite(LED_BUILTIN,HIGH);
    }
  }

then the LED will turn-on when you bring a magnet near the sensor, and the LED will turn-off when you move the magnet away. Simple. :)

[ghiglie]

Great!
A bit OT: how are you programming the nRF?

[NeverDie]

@ghiglie I plug it into the nRF52 DK using an IDC cable to its 10-pin connector. Then just select J-Link as the programmer and upload my sketch over the USB port connection to the nRF52 DK from within the Arduino IDE. Easy!

[DerManni]

@NeverDie
Did you or anybody else could write to the NRF5xxx via the Arduino IDE and a ST-Link V2 programmer?
I find the DK for approx. 32€ a little bit to expensive for just testing.

Edit: Maybe this one could work:
http://s.aliexpress.com/FRzU3miM

Thanks.

[NeverDie]

@DerManni said in 💬 Multi-Sensor: Temp/Humidity/PIR/ Leak/Magnet/Light/Accel:

ST-Link V2 programmer

Not me. As I said, I'm using the nRF52 DK as my programmer of choice. I think others may be using the ST-Link V2. Not 100% sure though.

[rmtucker]

@NeverDie
Yes i am using the STLink v2 without any problems.

[DerManni]

@rmtucker Could you please explain in weich was you connect the STLINK to the NRF Module to usw the Arduino IDE. Thanks