Reporting sensor data from standalone arduinos

#1

Hello. Last night I configured an esp8266 gateway and integrated it into MQTT/Home Assistant/Nodered with a couple of off the shelf 433mhz devices. So far so good, I love the project!

Now that I have a working gateway, I wondered if it’s possible to send data to the it via RF from standalone arduinos (possibly just using bare 328 chips for power saving) fitted with 433 tx modeuls placed in remote locations on battery power.

I invisige these would be in deep sleep and report temperature/humidity/distance and perhaps other data back every x minutes.

Is this something that can be done? I realise there are probably sensors out there I can buy which would be easier to integrate but I like to diy where possible, so I thought I’d ask the question.

Thanks

#2

Hello,

Glad you like it!

Yes you can build your own sensor based on ATMega328 here is some ideas:

The most difficult thing is to change the atmega328p internal bootloader.

This website has very interesting infos:
https://www.gammon.com.au/bootloader

And just in case this sensor is compatible with ZgatewayPiLight :slight_smile:

Hope this help.

#3

Thanks very much for this. I will have a go and let you know how I get on. I remembered that I have a TPL5110 sitting at home, so I might just use this instead to achieve the power savings.

#4

So far so good. The data is flowing into home assistant nicely with a value template to filter the key and the power usage isn’t bad.

I estimate 25mA while transmitting and the spec sheet of the TPL5110 is 20uA so that’s higher than yours. I might have a go changing the bootloader and using deep sleep instead.

#5

Hello, glad you get it working ! For my curiosity what kind of battery are you using ?

#6

Same as yours 3xaa. I’m thinking about making a more compact version for monitoring a fridge with 2xaa but I’m not sure it will provide enough voltage

#7

are you using an arduino or a bare atmega328p finaly?

#8

I have been using a bare 328p but with an external crystal. I have read that I can use 3v if I change from 16 down to 8mhz which means flashing the bootloader like you mentioned.

I’ve also tested with an attiny85 and that works well on 2xaa (I only need 2 i/o pin for each of the 3 projects I have in mind).

1 Like
#9

Here is the 1 year voltage view from the lion I made in 2016:

I have lost some data due to sdcard corruption… but here is the values reported in 2017:
|2017-07-02 20:56:31|4541|
|2017-07-02 21:47:14|4523|
|2017-07-02 21:47:15|4523|
|2017-07-02 23:28:42|4541|
|2017-07-03 01:10:10|4523|
|2017-07-03 01:10:11|4523|
|2017-07-03 02:00:54|4523|
|2017-07-03 04:33:06|4541|
|2017-07-03 06:14:33|4541|
|2017-07-03 06:14:34|4541|
|2017-07-03 07:05:17|4523|
|2017-07-03 07:56:00|4523|

and a recent one:
2019-04-07 21:13:22 4365

It seems that it will still live years