My Slim 2AA Battery Node

[AWI]

@m26872 I have assembled 6 boards now and am very happy with the design. I use strips as a socket for the Atmega. This leaves enough room for components under it. Also made one with SPI connector. Works perfect! Thank you for sharing the design and instructions.

[m26872]

@AWI Great idea with the strips! And thanks for verifying (v1.2?).

[m26872]

I've now ordered yet another prototype version (1.4):
http://dirtypcbs.com/view.php?share=13310&accesskey=58c87fe605eb91958938f70b5efc8629

Eagle brd-file.

Photo here.

[m26872]

I bought a few enclosures... "mini trunking" seems to be the correct term. This time it was ABS and a little more clear white colour and glossy finish. I think I spent around 2hrs cutting them nicely into >200pcs. 50% 23cm and 50% 19cm lengths.

[Didi]

You want to make your town mysensors :joy:

[hek]

@m26872
200pcs!! What the heck are you up to?

[AWI]

@m26872 I think I used version 1.1? Did you change any of the wiring in the newer versions?

[m26872]

@hek
hehe, I had a hunch it'd be spectacular. Let's just say that I aim to have a few single sensor/purpose sleeping nodes, but probably not 200. At least not in a while.

[m26872]

@AWI Ops sorry, I meant v1.0. I see the larger pads in your pics. The routing is a little different to 1.2 and 1.4. Mostly related components under the uC.

[ar91]

Very nice design. Any video on installation of bootloader with various settings described in the original post?.

[m26872]

@ar91 Thx. Sorry no. I don't know of any and I'm too shy to do it myself.

[ahmedadelhosni]

Great idea using this housing.

Why didn't you use CR batteries to decrease size ?
http://www.digikey.com/product-detail/en/CR1220/P033-ND/269740

[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)