Creating an Eddystone beacon?

[Lucio Flavio]

This post is deleted!

[b.veen]

Hi everybody, I have come a little step closer to my goal.
By using bluetooth.set_advertisement(service_data=bytes([0xAA, 0xFE,0x10,0xF8,0x00,ord('p'),ord('y'),ord('c'),ord('o'),ord('m'),ord('.'),ord('i'),ord('o')]))
the WiPy is simulating a 'Physical Web Beacon' with the Eddystone Url http://www.pycom.io

The framedata looks like this
LEN, TYPE, VALUE
2, 0x01, 0x06
2, 0x0A, 0xEB
5, 0x12, 0x20004000
14 ,0x16, 0xAAFE10F8007079636F6D2E696F

Question is: how to add the field 'Complete 16 bit service UUID list' containing the Eddystone uid (AAFE) ?
I would expect it should be possible to add this line to the raw data above.
LEN, TYPE, VALUE
0x03, 0x03, 0xAAFE

[b.veen]

I actually managed to get the 16 bit UUID in the frame by using the full 128-bit ID.

from network import Bluetooth
b = Bluetooth()
b.init()
b.advertise(True)

uuid = bytes([0xfb, 0x34, 0x9b, 0x5f, 0x80, 0x00, 0x00, 0x80, 0x00, 0x10, 0x00, 0x00, 0xaa, 0xfe, 0x00, 0x00])
data = bytes([0xAA, 0xFE, 0x10, 0xF8, 0x00, ord('p'), ord('y'), ord('c'), ord('o'), ord('m'), ord('.'), ord('i'),ord('o')])
b.set_advertisement(service_uuid=uuid, service_data=data)

This seems to work to create an Eddystone URL frame.
But, to be Eddystone compliant you need an UID frame too.

The frame takes all 32 bytes, so there is no room for extra information.
The Pycom framework unfortunately adds TX power and beacon interval information. This is hardcoded in modbt.c

adv_data.set_scan_rsp = false;
adv_data.include_txpower = true,
adv_data.min_interval = 0x20;
adv_data.max_interval = 0x40;

[papasmurph]

@b.veen You don't have to advertise UID as well. TLM is practical though. I got it working too, but from where did you get the UUID?

[b.veen]

@papasmurph
For my purposes I do not need TLM so I did not try to get that working.
My solution was to change the bluetooth.setadvertisement function to include an extra option to enable/disable the TX and interval information.

I have got the UUID working by providing the full google eddystone UID as registered on the bluetooth website. This resulted in a 'Complete 16 bit service UUD list'.

The broadcasting of the URL is working too.

(Since this project I have bought a couple of commercial beacons, it was fun experimenting with the PyCom though).

[papasmurph]

@b.veen Changing the firmware is not an option for me, considering how much maintenance is still done on it. E.g. continuous Bluetooth scanning (that I need in another project) is still unstable. The UUID insertion seems "magical", as the data is only partly available in the actual packet. I have a slew of dedicated beacons as part of my main offering CliqTags (I even sell beacons, not successfully though). What I'm experimenting with is making a remotely configurable beacon. Especially changing the URL for Eddystone would be interesting, so I've made a converter to the compressed URL format used by Eddystone. What remains is essentially pushing or pulling (more likely the latter, to avoid firewall issues) the URL.

[patrick]

@b-veen You have successfully implemented an iBeacon. I'm doing the same thing but struggling with the bluetooth.set_advertisement method. Can you help? What should I put in the manufacterer_data and what in the service_data? Should I put the complete 31 bytes in the manufacturer_data and in what order...

[surly]

I tried with data = bytes([0xAA, 0xFE, 0x00,
0x29,
0x00, 0x11, 0x22, 0x33, 0x44, 0x55, 0x66, 0x77, 0x88, 0x99,
0xAA, 0xBB, 0xCC, 0xDD, 0xEE, 0xFF,
0x00,0x00]) , but it doesn't work!

[papasmurph]

@surly I can help you with Eddystone-URL, if that's interesting, but this seems to be Eddystone-UID.

[surly]

@papasmurph yes, sorry! I mean the Eddystone-URL is ok, but what I really need is the Eddystone-UID ( also the IBeacon version would be usefull ) !

[papasmurph]

@surly Here's a complete example of iBeacon and Eddystone-URL. I don't have an example of UID or TLD, as I didn't need those.

In my iBeacon example, the UUID is encoded in the packet. That's the only UUID I needed (my own), but would be easy to create dynamically from a string.

from network import Bluetooth
import pycom
import time

# https://docs.pycom.io/pycom_esp32/library/network.Bluetooth.html
# https://support.kontakt.io/hc/en-gb/articles/201492492-iBeacon-advertising-packet-structure
# https://github.com/google/eddystone/blob/master/protocol-specification.md
# https://github.com/google/eddystone/tree/master/eddystone-url/
# https://forum.pycom.io/topic/1120/creating-an-eddystone-beacon
# https://www.mkompf.com/tech/eddystoneurl.html

MODE_IBEACON = 1
MODE_EDDYSTONEURL = 2
mode = MODE_IBEACON

def twocompl(x):
    if x < 0:
        x += 256

    return x        

timeSleep = 1

bluetooth = Bluetooth()
bluetooth.init()

power1m = -59

if mode == MODE_IBEACON:
    major = 22240
    minor = 234

    data = [
        0x4c, 0x00, 0x02, 0x15, # Manufacturer data
        0xA6, 0xE3, 0xE0, 0x06, 0xBB, 0xC4, 0x4D, 0xD1, 0x9C, 0xA3, 0x3E, 0x86, 0xC4, 0x95, 0x7D, 0xF0, # UUID (CliqTags)
        (major >> 8) & 0xFF, major & 0xFF, # Major ID
        (minor >> 8) & 0xFF, minor & 0xFF, # Minor ID
        twocompl(power1m) # Power
    ]

    bluetooth.set_advertisement(name = None, manufacturer_data = bytes(data))
elif mode == MODE_EDDYSTONEURL:
    url = 'https://www.abiro.com'

    uuid = [0xfb, 0x34, 0x9b, 0x5f, 0x80, 0x00, 0x00, 0x80, 0x00, 0x10, 0x00, 0x00, 0xaa, 0xfe, 0x00, 0x00]

    url = url.replace('http://www.', chr(0))
    url = url.replace('https://www.', chr(1))
    url = url.replace('http://', chr(2))
    url = url.replace('https://', chr(3))

    url = url.replace('.com/', chr(0))
    url = url.replace('.org/', chr(1))
    url = url.replace('.edu/', chr(2))
    url = url.replace('.net/', chr(3))
    url = url.replace('.info/', chr(4))
    url = url.replace('.biz/', chr(5))
    url = url.replace('.gov/', chr(6))
    url = url.replace('.com', chr(7))
    url = url.replace('.org', chr(8))
    url = url.replace('.edu', chr(9))
    url = url.replace('.net', chr(10))
    url = url.replace('.info', chr(11))
    url = url.replace('.biz', chr(12))
    url = url.replace('.gov', chr(13))

    data = [
        0xAA, 0xFE, # Eddystone ID
        0x10, # Eddystone-URL
        twocompl(power1m), # Power
    ]

    for c in url:
        data.append(ord(c))

    bluetooth.set_advertisement(service_uuid = bytes(uuid), service_data = bytes(data))

bluetooth.advertise(True)

while True:
    time.sleep(timeSleep)

[surly]

@papasmurph Great! it works! Thank you very much

[zaphodbb]

@papasmurph Thanks for doing the work to make the Eddystone beacon. I have your version up and running on WiPy 3.0. The eddystone beacon can send broadcasts the basic url but not a url with a path attached.

For example, if the url is https://pycom.io, the physical web app on my iphone gets the url and shows a notification. If the url is https://pycom.io/news, the phone app does not see any beacon.

Is this is a limitation of the bluetooth library? If so, is there a fix?

[jcaron]

@zaphodbb Have you tested with those specific URLs, or with different URLs?

There's a limit on the (compressed) URL length in the Eddystone format which you may hit if your URL is long. The two URLs you gave should fit, but https://forum.pycom.io/topic/1120/creating-an-eddystone-beacon/14 won't, for instance.

If you have longer URLs, you'll need to use an URL-shortener.

[zaphodbb]

@jcaron I used the two urls in my original post. I used the code from @papasmurph and added a print statement to look at the data bytes sent to the Bluetooth function. In both cases the data stream is properly formed.

When transmitting “https://pycom.io” it gets picked up by the physical web app on my phone. When I add the path “/news” and restart the code, the data stream is still properly formed but the app does not see an Eddystone beacon. Removing the path gets the beacon to be seen again.

My conclusion is that there is something happening when a path is added to the url. This is important as any shortened url (ie goo.gl/ads23g) won’t be seen.

[jcaron]

@zaphodbb I think the issue is that the code uses a long (128 bit) UUID instead of the short 16-bit UUID, so there's a very short limitation on the max URL size.

Try replacing the value of uuid with [0xaa, 0xfe] or 0xfeaa, it should give you 14 more bytes for your URL (haven't tried it).