@nca78 said in Best sensor for falling alert:

But except if there's an interest in using the gyroscope, IMHO it's a bit of an overkill, while a LIS3DH will use 50-100 times less current for free fall detection (between 6 and 11µA), ADXL345 over 10 times less (40µA)

I agree with this also especially due to the low current consumption. I would not go as far as dismissing something as overkill when considering the intended usage though.

I don't have experience with free fall detection systems but somehow it sounds more suitable for detecting a direct gravitational falling and not a person falling which likely involves legs slowing down and the fall starting from the person already standing on the ground. But I am definitely interested in hearing how this works out as this is one of those rare projects that isn't just a "nice to have". Great idea!

@daniel-oliveira said in MH-Z19 CO2 sensor:

TX, RX, GND and Vin

I can confirm only TX, RX, GND and Vin are needed. I've setup the device with a Wemos D1 Mini using the code found here https://github.com/jehy/arduino-esp8266-mh-z19-serial/

It's not MySensors related though, I've yet to try MySensors myself but registered to this forum to reply as I found this conversation while looking for code samples for the sensor.

You might get some tips from this interview on the Amp Hour podcast: https://theamphour.com/481-an-interview-with-paul-thompson/. If I remember correctly, Paul Thompson goes into details of the various issues he's encountered creating circuitry to work together with high voltage. If nothing else it is a fascinating interview to listen to.

@mrhutchinsonmn said in Best sensor for falling alert:

My sensors arrived in the mail the other day. For simplicity, I will be using the following devices:
ESP8266 microcontroller NodeMCU Lua V3 WiFi with CH340G
Wit-fancy Arduino GY-521 MPU-6050 Module 3 Axis analog gyro sensors 3 Axis Accelerometer Module
...
Hope to get started working through things in the next few days.

Good luck! I hope I won't sound pessimistic but I would suggest starting with measuring the power usage of the planned setup and/or testing if you can get it to acceptable level taking into account the battery you're planning to use. This way you'll be able to dismiss a particular sensor module (or the devboard) early on and not waste time figuring out how to get the fall detection code working with the setup.

I've found power consumption to be one of the most difficult part when considering battery powered devices.

You might get some tips from this interview on the Amp Hour podcast: https://theamphour.com/481-an-interview-with-paul-thompson/. If I remember correctly, Paul Thompson goes into details of the various issues he's encountered creating circuitry to work together with high voltage. If nothing else it is a fascinating interview to listen to.

@pierrot10 Maybe you could apply the same principle as with the soil sensor but attach to some stainless but conducting nails as you suggested. For calibration you could buy some cheap hand held meter: https://www.aliexpress.com/wholesale?catId=0&initiative_id=SB_20190919015529&SearchText=Wood+moisture+meter&switch_new_app=y ?

@mrhutchinsonmn said in Best sensor for falling alert:

My sensors arrived in the mail the other day. For simplicity, I will be using the following devices:
ESP8266 microcontroller NodeMCU Lua V3 WiFi with CH340G
Wit-fancy Arduino GY-521 MPU-6050 Module 3 Axis analog gyro sensors 3 Axis Accelerometer Module
...
Hope to get started working through things in the next few days.

Good luck! I hope I won't sound pessimistic but I would suggest starting with measuring the power usage of the planned setup and/or testing if you can get it to acceptable level taking into account the battery you're planning to use. This way you'll be able to dismiss a particular sensor module (or the devboard) early on and not waste time figuring out how to get the fall detection code working with the setup.

I've found power consumption to be one of the most difficult part when considering battery powered devices.

@nca78 said in Best sensor for falling alert:

But except if there's an interest in using the gyroscope, IMHO it's a bit of an overkill, while a LIS3DH will use 50-100 times less current for free fall detection (between 6 and 11µA), ADXL345 over 10 times less (40µA)

I agree with this also especially due to the low current consumption. I would not go as far as dismissing something as overkill when considering the intended usage though.

I don't have experience with free fall detection systems but somehow it sounds more suitable for detecting a direct gravitational falling and not a person falling which likely involves legs slowing down and the fall starting from the person already standing on the ground. But I am definitely interested in hearing how this works out as this is one of those rare projects that isn't just a "nice to have". Great idea!

Andreas Spiess just yesterday uploaded a very comprehensive comparison between the different LiPo powered ESP32 modules people on this thread might be interested about: https://www.youtube.com/watch?v=-769_YIeGmI

He has also posted a lot of other excellent ESP32 and LoRa videos. i highly recommend to check them out!

@daniel-oliveira said in MH-Z19 CO2 sensor:

TX, RX, GND and Vin

I can confirm only TX, RX, GND and Vin are needed. I've setup the device with a Wemos D1 Mini using the code found here https://github.com/jehy/arduino-esp8266-mh-z19-serial/

It's not MySensors related though, I've yet to try MySensors myself but registered to this forum to reply as I found this conversation while looking for code samples for the sensor.