My Slim 2AA Battery Node

[AWI]

@wergeld congratulations :thumbsup:
For the temp sensor I suggest a si7021 board. Almost the same price as as dht22 but more accurate, reliable and versatile. It uses the I2C bus (pin A4, A5)

[wergeld]

@AWI said:

@wergeld congratulations :thumbsup:
For the temp sensor I suggest a si7021 board. Almost the same price as as dht22 but more accurate, reliable and versatile. It uses the I2C bus (pin A4, A5)

@AWI I saw the si7021 on another forum. Ordered a couple of the low voltage ones as I want to make my nodes with as few components as possible. I could still use my thermistor while I wait. This is a fun build!

[Soloam]

Hello, I made a small modification to this project, hope that is ok! Now I need some help validating it! I opened a new topic to avoid going side topic in this one:

http://forum.mysensors.org/topic/3642/m26872-slim-node-mod

Thank you all

[m26872]

@Soloam I'm happy that you've picked up the design. That's what this openhardware is all about. Also very good that you made a new topic! So, let's continue there. I'll follow.

[rollercontainer]

I ordered a proto pack on 15th of April and received it on 30th of April. Pretty fast, I think. :-)

[rollercontainer]

Hm, I built some nodes and messured the current with a Fluke 179: 15mA even with a minimal sketch with sleeping enabled. AVRs are not from china, but the NRF24 are. So, is the radio the problem?

Greetings

[rollercontainer]

(i am using MySensors 2.0.0beta)

[m26872]

Could be radio, but who knows? What troubleshooting steps have you taken? Hw-, sw-variations etc. Please post your sketch. Perhaps are there any SlimNode users with working MyS 2.0.0 beta that can share some info.

[GertSanders]

@m26872
I have had a bad radio which would not go to sleep and consumed around that amount all the time (also when I used SLEEP in the 2.0 library).

Switching the radio to another one fixed it. All my radio's are from China, so they are normally OK. But you can get bad ones once in a while. Given the low cost I do not care and swap them when needed.

[rollercontainer]

Ok, where to buy NRF24's which are genuine for sure and not too expensive in europe?

[GertSanders]

@rollercontainer
No idea, I'm quite happy with the radio's from China (1 bad one on 25 pcs so far).

[rollercontainer]

Thx, Gert. Are you using 1.5 or 2.0.0beta?

[GertSanders]

@rollercontainer
I use the 2.0 beta

[rollercontainer]

Bought another 2 radios from different dealers. The one with the blob on the die is going down to 2mA, but isnt working at all (node does not come up). The next one is working, but again 15mA. This is frustrating. Anyone here with a good source for radio modules?

Even with a stripped down sketch without any sensors with only delay and sleep in the loop, the current stays the same.

[GertSanders]

@rollercontainer
I get my radio's from an Aliexpress store called AAA+ (or something with a lot of A's in the name).

[Bobcat]

@26872, It's my first post here and I had to register so that I could give you my regards for your work and for sharing it with us! Just ordered a batch of your v2 boards.

I have similar design sensors running on proto-pcbs, but your ready-made pcb makes everything much more convenient.

Just had a question on stability of running regular Arduino 8mhz internal clock bootloader for prolonged time. Anyone tried this and had success running the 328 down to 2v (or so) @ 8mhz? If this is a doomed idea, I will have to attach the boost circuit to this design, but it would be nice to avoid all that parasite current consumption.

[GertSanders]

@Bobcat
I have had an atmega328 run down to 1V6 at 8Mhz before failing completely, so working down to 2V should be OK. The nrf24 will likely stop around that point as well (lower limit is 1V9 for that chip).

[Bobcat]

@GertSanders
Thank you for the reply! Was the atmega doing some clock critical tasks when it went below 2v? I am thinking to attach BME280 (Pressure/Temp/Hum) which also operates in the same voltage range, but not sure if the I2C will be working properly when atmega goes overclocked.

[GertSanders]

@Bobcat
The nice thing about I2C is that the clock is generated by the atmega328 (the master), so even if this clock slows down due to low voltage (this happens a little when using the internal oscillator), the I2C devices on that bus just follow.
We can also use SI7021 (temperature and humidity sensor) at these low voltages for the same reason.

[badmannen]

Hello all

I´m Henrik, first post here and sort of beginner at this ( use to do some embedded stuff some 15 years ago and picked it up again recently )

I just did a shopping list for this project, Version 2.0 if I got it correct =)
here it is: http://my.aliexpress.com/wishlist/shared.htm?groupId=3106453469
As an example it should be about 20 euros if you buy to be able to make 5 whole sets.

I added 3 additional and optional things to the original BOM:
battery holder + battery connector to make it easier to change them ( I think )
straight pins

I did this for people searching for the components needed that does not have any or very few before starting the project.

Only thing extra needed I think would be some additional cable and a arduino UNO or some other way to program the single chips. But I assume you already have a UNO if you read this :)
And a soldering iron and that stuff.

(if even one person found this useful I guess it fulfilled its purpose)

//Henrik