My Slim 2AA Battery Node

[mfalkvidd]

2AA batteries have approximately 2000mAh capacity. CR1220 has 35mAh. So for the same capacity, more than 50 CR1220 would be needed. That wouldn't save space :)
But CR1220 has lower self-discharge so they can be a good alternative for things that are really low-power, or don't need long battery life.

[m26872]

@ahmedadelhosni I've read a few reports from people with radio module issues after some time on CR "coin cell" batteries. The expected battery life time then doesn't match the result. I think you can find references by searching.

[martkrui]

m26872, I just wanted to say thank you for your work on this project and for sharing it with everybody. :+1:
I've just ordered the ATMEGAs to build 5 nodes.
How confident are you about the V1.4 PCB ? If you don't see any issue with them at this point I think I'll take the whopping $14 risk :yum:

[ahmedadelhosni]

Aha..now I understood the reason. Thanks

[m26872]

@martkrui I'm not confident until I've tested one, but usually errors can be fixed with some ugly mods if necessary. ;-)

BTW I added to the info that any/every DirtyPCB money from this share will be donated to MySensors.org.

[betonishard]

Like the board and ordered it. Can you also post exactly the capacitor types? Keep up the good work.

[martkrui]

I also ordered the PCBs (at my own risk) and some of "TMK-T20 20mm 17mm"
I'll try to CNC or 3Dprint some endcaps or something.

[m26872]

@betonishard There aren't any exact values or types, but good start would be

Near the radio supply: One radial electrolytic >=4.7uF >=10V capacitor together with one ceramic (range 1pF - 1uF. I use different.).

The rest (C1, C2, C3): 0.1uF ceramic, where the value probably matters most for C2 (the Reset capacitor)

[betonishard]

@m26872
Thanks... Maybe it is answered, but I didn't quite catch it. 3v will be fed to the radio, but isn't the 3.3 important instead of 3v? I don't see any stepup. Is your range acceptible?

Thanks...

[mfalkvidd]

The radio can handle as low as 1.9V (source)

[GertSanders]

I have had a node sending messages as low as 1.65V :-)

[betonishard]

@mfalkvidd @GertSanders Thanks for your answers!! How about the range, I know it is depending on the quality of Chinese products, however can you give an estimate regarding your setups?

[mfalkvidd]

Short answer: Expect about the same range as a regular wifi card.
Long answer: Look at these informative and quite entertaining videos:
Ultimate nRF24L01 range comparison
nRF24L01 range test (arduino)
nRF24L01 range test part 2 (arduino)

[ar91]

I was about to order the 1.4v of your board before that i wanted to ask you a basic question, do i need to use any step up regulator to connect any 5v sensors? Have you connected any 5v sensors, if yes could you please post some pictures?

Thanks again for the great work.

[GertSanders]

You will indeed need to use a step-up regulator to use 5V sensors, as his board is 2AA battery based (gives maximum 3.2V on fresh batteries). For quite some sensors, you will find 3V3 versions, which can work at even lower voltages. look for sensors which work down to 1.8V-1.9V
Using 5V sensors in a battery based node is not efficient.

[ar91]

@GertSanders Thank you so much. Is there a recommended list of low voltage sensors? The Mysensor store only has 5v sensors i believe. I will other search other forum post as well. If anyone know from top of their head please list it.

Temperature sensor - ?
Humidity sensor - ?
Luminosity sensor - ?
PIR - ?
Infrared sensor -?
Soil Moisture sesnor -?

[Cliff Karlsson]

I also was about to order the 1.4 board. But are there any list of components that I need to complete the board?

[m26872]

@Cliff-Karlsson Sorry for late reply. I've not yet a BOM. I'll try o fix it later.

[m26872]

NEWS:

• A "final" version 2.0 redesigned i KiCad (very similar layout), panelized, ordered and tested OK.
• A faulty via was introduced during panelization of v1.2, so the panelized v1.2 (blue board) needs a small fix to work.

More info ASAP.

Edit 4/11: There seems to be no issues with v1.4 (red board) as I thought first. Luckily since it's now been shared a few times.

[AWI]

@m26872 I received the boards yesterday. Can you direct me to the fix needed.?