LoPy stops detecting BLE advertisements

[jcaron]

@alanm101 did it stop finding any BLE advertisements at all, or specifically those you were looking for?

[alanm101]

Apologies for yet another post. Please issue a cease and desist if this it too much.

Anyway, back at the hotel, and further tests (sans my serial monitor that's pining away at home). Perhaps the complexity of the demo environment was a factor. The code I'm running now at the hotel suggests that volume of BLE advertisements overwhelmed the chip. So one must figure out how to code around this. A callback that intelligently discards? I'm getting out of my depth on this and will happily accept derision from the community but would prefer constructive guidance.

[alanm101]

@jcaron All advs. I specifically put in debug code to determine this. As mentioned, the machine.reset() had no impact, yet a physical reset via the reset button got the BLE scanning showing results.

[alanm101]

No code change. No power supply change. At the hotel, no problems. The hypothesis that the chip can't handle technologically complex environments appears to have some merit.

Hopefully a community member will highlight a solution.

[jmarcelino]

@alanm101
I'm afraid it's impossible to highlight any correct solution based on so little information.

You're saying that the module - mounted on the expansion board, not a breadboard or something custom - stops scanning BLE beacons in "complex technological environments"?

Can you post what appears in the serial output (from the Expansion Board USB port) from the module when this happens? This is crucial to understanding - and potentially fixing - the problem.

[jcaron]

I wouldn't be too surprised if some specific advertisements could break the scanning code. However without an idea of what that advertisement could be, it might be difficult to find out.

If you have some other device that can capture all BLE advertisements, it could be useful to get that capture so that each advertisement could then be tested again the BLE code to see how it handles it.

[alanm101]

@jcaron @jmarcelino Thanks for the comments guys. I will be spending quality time on this and will give feedback sometime. No problems when it ran all night at the hotel. Only my 4 iBeacons in range though.

[alanm101]

@papasmurph Please help me understand how you posted the code? When I try pasting inline, it's a mess. I don't have permission to upload a file.

[papasmurph]

@alanm101 Three left apostrophs (```) on separate lines before and after the code.

[alanm101]

@papasmurph Thanks!

[alanm101]

@jmarcelino My goodness j, I'm embarrassed. Somehow I concluded that the expansion board has a separate debug serial output. So I hooked up on pins G1, G2 and GND as per other posts and found it's the exact same serial output as via the MicroUSB serial output. I'm seeing no extra output other than my own debug print statements. I will post the full source code and the serial output a little later.

[alanm101]

@jcaron @jmarcelino Here's the code and the serial output. You will notice that, without warning or raised exception, the scanning becomes unsuccessful at around 3450 seconds (58 minutes). That's indicated by the repeated beacon ID and rssi, despite having moved that beacon out of range when the repetition started. As always, advice greatly appreciated. Options: a) repeat test on Lopy using standard espessif's standard firmware, b) repeat test with a standard ESP32.

from network import Bluetooth
import pycom
import time
import gc
import binascii
import machine

mybeaconids = ['d3e0f6cd4ca9','eea068fa3738','f51e1bced835','ea204c29bb1f','e9f1db4814ef']
enditall = False

pycom.heartbeat(False)
timeSleep = 0.01

bluetooth = Bluetooth()
starttime = time.time()

devid = ''
rssi = ''

def new_adv_event(event):
    global devid, rssi
    if event.events() == Bluetooth.NEW_ADV_EVENT:
        anydata = True
        while anydata:
            adv = bluetooth.get_adv()
            if adv != None:
                devid = binascii.hexlify(adv[0]).decode('utf-8')
                rssi = str(adv[3]*-1)
            else:
                anydata = False

bluetooth.callback(trigger = Bluetooth.NEW_ADV_EVENT, handler = new_adv_event)

print('Starting BLE scan')
bluetooth.init()
bluetooth.start_scan(-1)

p_in = machine.Pin("G17",machine.Pin.IN, pull=machine.Pin.PULL_UP)

loopcnt = 0
while True:
    loopcnt += 1
    if not bluetooth.isscanning():
        print('--------- Restarting BLE scan')
        bluetooth.deinit()
        bluetooth.init()
        bluetooth.start_scan(-1)

    # to keep the log manageable, print details only every 500 loops.
    if loopcnt%500 == 0:
        print(time.time() - starttime, devid, rssi)
    if p_in() == 0:
        print('pin')
        break
    time.sleep(0.05)

bluetooth.callback(None)
bluetooth.stop_scan()
bluetooth.deinit()

print('Run time in seconds ', time.time() - starttime)





------  Serial output. 


rst:0x1 (POWERON_RESET),boot:0x13 (SPI_FAST_FLASH_BOOT)
ets Jun  8 2016 00:22:57

rst:0x10 (RTCWDT_RTC_RESET),boot:0x13 (SPI_FAST_FLASH_BOOT)
configsip: 0, SPIWP:0xee
clk_drv:0x00,q_drv:0x00,d_drv:0x00,cs0_drv:0x00,hd_drv:0x00,wp_drv:0x00
mode:DIO, clock div:1
load:0x3fff9010,len:12
ho 0 tail 12 room 4
load:0x3fff9020,len:388
load:0x40078000,len:11584
load:0x4009fb00,len:848
entry 0x4009fc9c
Starting BLE scan
25 f51e1bced835 74
50 6c8009ac5ece 71
75 d5e2f8cf4eab 76
100 7e0504d53526 51
125 e9f1db4814ef 73
150 7e0504d53526 49
175 7e0504d53526 52
200 730088c7c467 49
225 6c8009ac5ece 78
250 6c8009ac5ece 72
275 d5e2f8cf4eab 75
300 d5e2f8cf4eab 75
325 d3e0f6cd4ca9 67
350 7e0504d53526 49
<snip>
...
</snip>
2850 6c28333b9548 52
2875 73bc08769bce 62
2900 d5e2f8cf4eab 66
2925 f7201dd0da37 76
2950 73bc08769bce 61
2975 6c28333b9548 50
3000 73bc08769bce 59
3025 d5e2f8cf4eab 63
3050 73bc08769bce 62
3075 ea204c29bb1f 69
3100 73bc08769bce 58
3125 73bc08769bce 58
3150 73bc08769bce 58
3175 6c28333b9548 51
3200 6c28333b9548 51
3225 73bc08769bce 62
3250 d3e0f6cd4ca9 63
3275 6c28333b9548 50
3300 73bc08769bce 58
3325 d5e2f8cf4eab 63
3350 6c28333b9548 51
3375 d5e2f8cf4eab 63
3400 6c28333b9548 50
3425 6c28333b9548 51
3450 73bc08769bce 62
3475 73bc08769bce 62
3500 73bc08769bce 62
3525 73bc08769bce 62
3550 73bc08769bce 62
3575 73bc08769bce 62
3600 73bc08769bce 62
3625 73bc08769bce 62
3650 73bc08769bce 62
3675 73bc08769bce 62
3700 73bc08769bce 62
3725 73bc08769bce 62
pin
Run time in seconds  3743

MicroPython v1.8.6-776-gd01a46cd on 2017-09-29; LoPy with ESP32
Type "help()" for more information.
>>> 

[jmarcelino]

@alanm101
Thank you, that information is very helpful.

Yes it would be interesting to compare with the C level ESP-IDF code on the ESP32.

I'll look into it in the coming days.

[jcaron]

@alanm101 What's the advertising interval of your beacons? If you change the advertising interval or the number of beacons, does the time scanning fails change?

[alanm101]

@jcaron Time to failure is random. Just ran another test in same controlled environment (home). Failed after 13 minutes.

Unfortunately I'm using Estimotes that cannot be transferred to me so frequency is a) fixed, b) unknown. The Estimote app refuses to divulge the info. Nordic's app can't list it either. If it will help, I can move them out of range and turn my phone into an iBeacon for a new test.

Update: Can't seem to set update frequency for virtual beacon. At least not with the software I have.

[jcaron]

@alanm101 AFAIK there’s no frequency selection in BLE, it uses frequency hopping on predefined frequencies.

[jcaron]

@jcaron ah sorry you meant the frequency of the advertisements. It’s usually not possible to find on the receiver side (as it does not necessarily listen all the time), but there are often ways to change it on the beacon (it’s a matter of compromise between time to discovery and power consumption)

[alanm101]

@jcaron Yes, I meant broadcast rate/frequency. Apologies. Sadly I can't configure these.

[jcaron]

@alanm101 this: https://community.estimote.com/hc/en-us/articles/204100806-What-are-the-default-settings-of-Estimote-Beacons-How-to-edit-settings- says you should be able to adjust them.

Alternatively you may want to try to see if varying the number of beacons has an influence on the time to failure. Just in case it’s a simple matter of the code failing after receiving a given number of advertisements (which would also explain the issue you had at the exhibition).

[alanm101]

@jcaron Sadly, you have to "own" the Estimotes to make changes. The ones I have were allocated to someone else who now has no access to the registered email.

I'm running a test with the native IDF on a DOIT ESP32 board. Hacked the gatt_client.c code. No problems so far (58 minutes).