LoPy Nano-Gateway

[kgadeshi]

@Roberto
Is it possible to implement some kind of ranging algorithm in LoRa. So that one can calculate the distance between the nodes to the gateway or something along those lines? Thanks.

[livius]

time measurement should be then in nanoseconds i believe
you can send signal and wait for receive and calc distance divide time by two ;-)

[daniel]

@kgadeshi with the RSSI of the received packet and knowing the amount of power that was used to transmit it, the free space loss formula can be used to estimate the distance between the 2 nodes.

[Batilan]

You might also have a look at these resources:

• An extensive discussion on the TTN forum
• An article by Linklabs stating the issues especially for LoRa (they do have competing products, but the reasoning seems sound)

[Xykon]

After quite a bit of trial and error I have managed to get the LoPy to "talk" in P2P mode to a Dragino LoRa/GPS hat (which uses the same SX1272 chip that's in the LoPy.

For anyone interested I have posted some more details here and have made the source code for the LoPy and Raspberry Pi available on github.

[arista]

This is extremely exiting, since I have exactly the same hardware! I hope I'll have some time this month to test your code, @Xykon, and make the bits fly.

[angel.imaz]

Hello.

It would be great to get a proper tutorial on how to do a http request from a lora through a nano gateway.

I backed you in KS because you made a big point of making this possible. It is great to have the device. But really not very user friendly at all. And you are already launching a new one with more radios. Yet you still have not make LoPy work as promised.

Please help!

Thank you!

Angel

[bioagbob]

Ditto. What's LoRa without a gateway!? Time for proper documentation on this product feature.

[daniel]

@angel-imaz please see my post here:

https://forum.pycom.io/topic/98/lopy-as-lorawan-basestation/20

Our team is working on examples and there will be in the docs soon. If you need a HTTP client library, please try this one out: https://github.com/micropython/micropython-lib/tree/master/http.client

[Oneillsite]

A good way to test it:
2 Lopy's with PymakrBoard connected on 2 usb ports
2 instances of Pymakr

[microman7k]

Hi,

I test this sample but after about one hour of working i get "ValueError: buffer too small" on nano gateway. Any clues why?

Firmware: (sysname='LoPy', nodename='LoPy', release='0.9.7.b1', version='v1.8.6-234-g765f2bc on 2016-12-02', machine='LoPy with ESP32')

Best Regards

[Oneillsite]

@microman7k Hi, first of all you should update the firmware of your Lopy.

[microman7k]

@Oneillsite On the latest firmware (1.0.1.b1), results are even worse. After one event i get:

execfile('nanogw.py')
D: 1 P: b'22.5'
E (200196) wifi: error malloc bcn_param

Traceback (most recent call last):
File "<stdin>", line 1, in <module>
File "nanogw.py", line 20, in <module>
ValueError: buffer too small

[Oneillsite]

@microman7k i can't figure out why the message mention "wifi"...

[borjam]

I have been playing with it, actually receiving the packets on a Raspberry Pi with a Dragino Lora+GPS Hat and it works. (The "hat" is based on the SX1276).

There is a possibility of making an ugly hack in order to support multiple channels for a gateway. It wouldn´t be a multi channel gateway, but a channel hop capable gateway :)

The trick (I'll try next week) is to use the CAD functionality. Given the length of the prefix it may be possible to do something like this:

• Set frequency

• repeat
  CAD
  if CAD_DONE // this means timeout
  next frequency in list
  until CAD_DETECTED

. receive packet

It may be a bit tight, but it should be possible to monitor three frequencies. I'll get back with the results.

[microman7k]

@Oneillsite

Hi, on latest firmware version (1.2.0.b1) you get "MemoryError: parser could not allocate enough memory"

execfile('nanogw.py')
Traceback (most recent call last):
File "<stdin>", line 1, in <module>
File "nanogw.py", line 23
MemoryError: parser could not allocate enough memory

Pycom, can you please provide working sample with the latest firmware version or is this another bug?

[lmetcalfe]

@microman7k
I am getting same error.

[daniel]

Hello,

We are checking what's happening with this nano-gateway example and we'll get back to you shortly. The memory error can be explained due to the newly added interrupt handler task which is using some of the GC memory and the Bluetooth system also consuming a big chunk. Espressif is due to provide some good memory optimizations to sort this out and give us back several tens of KBs of precious RAM.

[lmetcalfe]

@daniel
It would be great if the RAM is not consumed if we do not use some modules like BT or Wifi or Lora as many applications may only use one of these radios. In my case I only use Lora.

[iber]

Would it be possible to use SSL on the LoRa with f.e: ssl.wrap_socket to secure it with a self signed certificate?