I asked this question to @Tweetonig a while back, and they thought a PCB size close to a (large) coin cell battery size should be possible. You would have to fit in an SX127x and small MCU on the non-battery side, plus some antenna, but I guess smaller than the mdot should be possible.
@turiphro @thinginnovations Definitely possible. Size constraints is now limited by how much you like to spend on development.
But the more popular the LoRa wan stack will become, the more chips we will see. I already looking forward to radio and mcu in a single package (like nordic did for BLE). That will bring the size down considerably.
Yes check out these puppies: http://www.anarduino.com/miniwireless/
Just ordered a couple of MiniWirelessLR-95-868Mhz modules to complement my current set-up.
As they are only Atmega328P mcu, they are unlikely to be able to hold a full LoRaWAN stack and provide something useful. Also, the HopeRF modules on there are not, in my experience, great. I’m not sure if the chip on there is an actual Semtech SX1272, a licensed copy or a knock-off compatible clone. The datasheet appears to be based on the SX1272 but with slight variations in places from when I initially looked at these almost a year ago.
There are a number of other mcu options that would be more capable, for example if they came with the Atmega1284P or one of the low power Arm based mcu from STMicro or Freescale then these might be a better option if you were to design your own if you’re capable.
For now I’m sticking with ready made modules and designing for these as I dont have a need to go to a tiny scale device just yet.
This is my hardware. They are LoRa nodes. I could make them the size of a 1 euro piece.
Teensy + HopeRF, running IBM LMiC stack.
really cool. you seem to be using the same chip as i do. i didnt stack the IC’s yet. but i like your setup. is it Wifi capable?
No Wifi, I used them for battery powered nodes.
Do you use the HopeRF board?
I actually also have nodes with the ESP8266, but do you maybe know how to switch the WiFi off, and keep the CPU running (to reduce power)?
Could you pls provide a little more detail about this node solution? Which HopeRF board are u using exactly? And how did you wire it to which teensy?
I have documented this node on the wiki page:
Look under ‘HopeRF’. Note that the software is work-in-porgress. It does work, but there is more todo.
oh, thanks for pointing me to the wiki.The iot information is spread over so many places…
That’s why we have a wiki.
This looks great, do you have a schematic i could follow to build one too? What kind of power consumption are you looking at? I want something that can run on a small coin li-on battery.
Holla everyone, please PM for skype address if you want more information.
Its currently mostly R&D
when I look at your foto of this nice little node I suppose to see some differences in wiring compared to this one: http://thethingsnetwork.org/wiki/Hardware/OverviewNodes
Connect the RFM92/95 to the Teensy:
Teensy LC/3.1/3.2 – RFM92/95
GND – GND
3.3V – 3.3V
2 – DIO0
5 – DIO1
6 – DIO2
9 – RESET
10 – NSS
11 – MOSI
12 – MISO
13 – SCK
could you please document your wiring?
what did you change in the IBM LMIC except the RFM-definition (RFM92/RFM95)?
why I ask? my node (arduino + hope xbee shield + xbee-adapter + rfm96w) failed with radio.cpp:657
I think I looked at the wrong MISO/MOSI definitions on teensy. right?
sorry for disturbing the forum
The little node on the photo indeed has slightly different wiring, but only on the DIO pins.
Are you using an RFM96W? The IBM LMIC library does not support the 433 Mhz band.
The error you’re getting either implies the SPI bus in not working (don’t cross-connect mosi/miso, but follow the connections as on the wiki), or the RFM96W has another version identifier than the RFM95W (=SX1276).
just an idea … is this feasible ?
sorry a typo, I’m using a HOPE RFM95W/868MHz
my node (arduino + hope xbee shield + xbee-adapter + rfm95w)
IBM LMIC with change in lmic/config.h
#define CFG_eu868 1
//#define CFG_us915 1
//#define CFG_sx1272_radio 1
#define CFG_sx1276_radio 1 <----
It would be nice, having a debug program printing all registers out and a library with extended debug statements …