Led lamp flickers visibly at low brightness

[BigMike71]

PROBLEM DESCRIPTION

Led lamp flickers visibly at low brightness, sometimes more sometimes less.
I have several Teckin SB53 (and also other brands) where it stands out with a setting of color # 0000000001 or # 0000000002! (for rgb low level's flickering is visibly too!)
When testing different versions, there is no flickering up to version 8.1.0.4, after which this occurs, even with the latest 8.2.0 release.
in the Arduino Core I found them here:
esp8266/Arduino#7054
esp8266/Arduino#7057

REQUESTED INFORMATION

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• Device used (e.g., Sonoff Basic): _____
• [ x] Tasmota binary firmware version number used: release 8.2.0_____
  • [x ] Pre-compiled
  • Self-compiled
    • IDE / Compiler used: _____
• Flashing tools used: _____
• Provide the output of command: Backlog Template; Module; GPIO 255:

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• If using rules, provide the output of this command: Backlog Rule1; Rule2; Rule3:

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• Provide the output of this command: Status 0:

  STATUS 0 output here:

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TO REPRODUCE

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EXPECTED BEHAVIOUR

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[s-hadinger]

This is very annoying, and I think I understand why it's causing flickering. Can you please try 8.2.0 and remove the file tasmota/core_esp8266_waveform.cpp?

The problem is that to remove a flickering when multiple PWM are set, it creates a new flickering with a single PWM.

[BigMike71]

I don't have the opportunity to build it myself, I only use the releases from https://thehackbox.org/tasmota/ and the github releases ...

[effelle]

@BigMike71 Please test the annexed build compiled with @s-hadinger instructions and report back, thanks.

firmware.zip

[BigMike71]

looks good, no more flickering!
I tested each channel individually with 01 or 02 and watched for several minutes.

[s-hadinger]

This confirms that your flickering was caused by my anti-flickering patch. Oh boy...

I tried to reproduce with my MagicHome led controller, and I can't see any flickering. Are only Teckin flickering or do you see this phenomenon on all your bulbs?

Can you also paste the result of Status 0, I have no clue about your configuration.

[BigMike71]

I can see it with all brands!
have Teckin, Gosund, AWOW, Bakibo, KingSO, ChangM (all are E27 / E14 from 4.5W to 13W) RGBW and RGBCCT

10:44:03 CMD: status 0
10:44:03 MQT: stat/tasmota/STATUS = {"Status":{"Module":0,"FriendlyName":["Tasmota"],"Topic":"tasmota","ButtonTopic":"0","Power":1,"PowerOnState":3,"LedState":1,"LedMask":"FFFF","SaveData":1,"SaveState":1,"SwitchTopic":"0","SwitchMode":[0,0,0,0,0,0,0,0],"ButtonRetain":0,"SwitchRetain":0,"SensorRetain":0,"PowerRetain":0}}
10:44:03 MQT: stat/tasmota/STATUS1 = {"StatusPRM":{"Baudrate":115200,"SerialConfig":"8N1","GroupTopic":"tasmotas","OtaUrl":"http://thehackbox.org/tasmota/release/tasmota.bin","RestartReason":"External System","Uptime":"0T00:00:28","StartupUTC":"2020-03-24T09:43:35","Sleep":50,"CfgHolder":4617,"BootCount":37,"BCResetTime":"2020-03-13T17:44:42","SaveCount":331,"SaveAddress":"F5000"}}
10:44:03 MQT: stat/tasmota/STATUS2 = {"StatusFWR":{"Version":"8.2.0.1(tasmota)","BuildDateTime":"2020-03-22T13:27:39","Boot":31,"Core":"STAGE","SDK":"2.2.2-dev(38a443e)","Hardware":"ESP8266EX","CR":"354/699"}}
10:44:03 MQT: stat/tasmota/STATUS3 = {"StatusLOG":{"SerialLog":0,"WebLog":2,"MqttLog":0,"SysLog":0,"LogHost":"","LogPort":514,"SSId":["HFDD",""],"TelePeriod":300,"Resolution":"558180C0","SetOption":["00108009","2805C8000100060000005A00000000000000","00000000","00000000"]}}
10:44:03 MQT: stat/tasmota/STATUS4 = {"StatusMEM":{"ProgramSize":577,"Free":424,"Heap":25,"ProgramFlashSize":1024,"FlashSize":1024,"FlashChipId":"14400B","FlashMode":0,"Features":["00000809","8FDAE397","043683A1","000000CD","010013C0","C000F981","00000004"],"Drivers":"1,2,3,4,5,6,7,8,9,10,12,16,18,19,20,21,22,24,26,27,29,30,35,37","Sensors":"1,2,3,4,5,6"}}
10:44:03 MQT: stat/tasmota/STATUS5 = {"StatusNET":{"Hostname":"Lampe-42-TECKIN","IPAddress":"192.168.1.242","Gateway":"192.168.1.1","Subnetmask":"255.255.255.0","DNSServer":"192.168.1.1","Mac":"68:C6:3A:ED:35:42","Webserver":2,"WifiConfig":2,"WifiPower":17.0}}
10:44:03 MQT: stat/tasmota/STATUS6 = {"StatusMQT":{"MqttHost":"192.168.1.200","MqttPort":1884,"MqttClientMask":"Lampe-42","MqttClient":"Lampe-42","MqttUser":"DVES_USER","MqttCount":1,"MAX_PACKET_SIZE":1200,"KEEPALIVE":30}}
10:44:03 MQT: stat/tasmota/STATUS7 = {"StatusTIM":{"UTC":"2020-03-24T09:44:03","Local":"2020-03-24T10:44:03","StartDST":"2020-03-29T02:00:00","EndDST":"2020-10-25T03:00:00","Timezone":"+01:00","Sunrise":"06:43","Sunset":"19:09"}}
10:44:03 MQT: stat/tasmota/STATUS10 = {"StatusSNS":{"Time":"2020-03-24T10:44:03"}}
10:44:03 MQT: stat/tasmota/STATUS11 = {"StatusSTS":{"Time":"2020-03-24T10:44:03","Uptime":"0T00:00:28","UptimeSec":28,"Heap":25,"SleepMode":"Dynamic","Sleep":10,"LoadAvg":79,"MqttCount":1,"POWER":"ON","Dimmer":1,"Color":"0000000003","HSBColor":"0,0,0","White":1,"CT":500,"Channel":[0,0,0,0,1],"Scheme":0,"Fade":"ON","Speed":2,"LedTable":"OFF","Wifi":{"AP":1,"SSId":"HFDD","BSSId":"7C:FF:4D:91:3E:DA","Channel":6,"RSSI":100,"Signal":-47,"LinkCount":1,"Downtime":"0T00:00:06"}}}

[s-hadinger]

I got back my old Teckin SB50, and indeed I can see some flickering at low brightness, but it's hard to see in plain light. Hmmm. I will try experimenting when it's darker.

[BigMike71]

ok.
my Teckin SB53 is a big bulb so its easy to see, my others need a darker room too...

[s-hadinger]

I removed the cap of the SB50, I can't see the flickering anymore...

Can you try with Fade 0. There may be a bug here.

[BigMike71]

i flashed back to 8.2.0 release, fade 0 but the flickering is visibly, i also switched off and powered down completly

[Dlay2017]

This appears also with Blitzwolf LT21

[s-hadinger]

@BigMike71 I switched to a new and better PWM implementation from Arduino Core in #8246.
Once it is merged, can you please try this version?

Edit: it is merged now.

[s-hadinger]

@BigMike71 one last thing you should do is lower the PWM Frequency: PWMFrequency 223

[BigMike71]

ok i testet so far, a longer test the next days.
seems to be good!
i only see, if i set the PWM Frequency to 223, the light is brighter than set it to higher than 223 !?

I am afraid that the low frequency can cause headaches or something else. there is some experience due to low frequencies in LED light. Experts say a frequency in the kilo heart is only certain. I have this page that deals with it: https://www.derlichtpeter.de/en/light-flicker/

with my smartphone and camera app you can also see that the 223hz flickers quite a lot (thick bars) at 880hz or more, it is significantly better! But the main problem is solved at first, since they are 2 different things!
thanx

[ascillato2]

ok i testet so far, a longer test the next days. seems to be good!

Great. Thanks. 👍