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Using a Trinket as a node

Added by JeffHerr about 5 years ago

Does anyone have experience using the Trinket from Adafruit as a node?
I’m most interested in your success getting wireless communication to work.


Replies (4)

RE: Using a Trinket as a node - Added by padvinder95 about 5 years ago

The JeeNode Micro is based on an ATtiny84, so flash- and ram-space-wise you should be fine. However, the Trinket is based on the ATtiny85, which only has 6 (5 according to the Trinket product page) I/O pins. The RFM12b radio unit needs 5, I think (clock, chip select, MISO, MOSI, INT). Maybe you could drop the interrupt line and switch to a polling-based library for the radio module, but even then you would only have 1 or 2 spare pins.

In short, not to promote JeeLabs stuff or anything, I would go for the JeeNode micro. While it is more expensive (€14 compared to \$8), this already includes the ~€5 radio; it has 2 standard JeeNode ports, or 2 analog + 2 digital I/O pins.

RE: Using a Trinket as a node - Added by lightbulb about 5 years ago

JeffHerr,

I agree with padvinder95, the std jeelib rfm12b lib will not help you much with the tiny85 based Trinket, not to mention that although they have similar ram to tiny84, the Trinket has a 'bootloader' that take some of the precious ram.
btw: you can desolder the trinket reset to get another i/o pin but thats still not going to help you much with rfm12b jeelib.
Also I think you will find that the correct port definition #defines are not in that lib anyhow.
As
padvinder95 says, there are polling solutions out there, but are also power consumers…..
I have tiny85’s deployed (using micronucleus) - some home-brew, others 3.3v Trinkets. Due to “pin starvation”, if i need them to ‘talk’ I normally use a 433 OOK SAW transmitter, and a rfm12b gateway on another node. 433 OOK only requires 1 i/o pin in addition to pwr/gnd (be aware of transmitter pwr requirements (vs distance) though if you go that way.

I am sure someone else will come along and provide other alternative advice.

—lightbulb

RE: Using a Trinket as a node - Added by JeffHerr about 5 years ago

Thanks for the advice so far. I’m not against using JeeNodes, but there is some allure to building it myself as well as having a reusable item should I want to disassemble and create something else in the future. (The bootloader is really attractive until I get my feet under me!)

Let’s assume it doesn’t make the most sense in the world, but one pin left is actually plenty given I plan to use OneWire temperature sensors almost exclusively.

“the std jeelib rfm12b lib will not help you much with the tiny85 based Trinket”
Can you help me as a noob understand your comment? Do I expect it will not work at all (even if I fix the #defines in the lib), or that it takes up so much memory there will not be enough room for other code/libs?

Thanks for hanging in there with me!

RE: Using a Trinket as a node - Added by lightbulb about 5 years ago

JeffHerr,

My comment was meant to indicate that the internals of the library were not compatible with 85’s when last I looked.

Can I instead point you to either digispark or Martin Harizanov’s trials : http://harizanov.com/2012/06/sending-jeelib-compatible-packets-with-attiny85rfm12b/

(That may actually be more specific to your current requirements).

Finally, the rfm12 code base is shortly due for revision. (maybe already revised) and this ‘may’ take it further away from Trinket territory, but then again, may take it closer. Others like johnO orjcw etc may shine more light.

—lightbulb

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