Wifi Shield — OpenBCI Forum

Does the SD card allow multiple data collections to be saved?

profeell — Mon, 25 Aug 2025 03:54:42 +0000

I'm planning to use the Wi-Fi Shield and Cython board to collect data and also want to save it to an SD card. However, I've noticed that the SD card only records data for a single session. If I stop and restart the session, the second data collection isn't written to the SD card. Is this normal, or did I do something wrong?

large EEG sample data amplitudes, how to process data stream

fnngn — Tue, 15 Apr 2025 01:54:48 +0000

Using Cyton Daisy Board, data is transmitted to the host computer via wifi, the sampling rate is 250hz, and the absolute value of the data I collected is between 15000 and 50000. The first question: If I multiply it by the 0.02235 scale factor as stated in the document, then my value is between 335 and 1117uv, but EEG signals are generally between 0 and 100uv. The second question: If I do not multiply it by the 0.02235 scale factor and directly pass the raw data through a 5~50hz filter, then the absolute value of the data is mostly between 0 and 100, but this time there is no multiplication of the scale factor, is this correct? The third question: If the raw data is multiplied by 0.02235 and then passed through a 5~50hz filter, the absolute value of the data obtained is between 0.05 and 0.5, which seems too small.
So how should the data be processed? I hope someone can help me, thank you very much

Wifi shield/Cyton not working after use

J_MCHA9782 — Mon, 11 Mar 2024 22:40:08 +0000

During a session, the cyton board/wifi shield seemed to crash after getting railed, and since then we have not been able to reestablish a connection with it or the board. The wifi shield will still show up in the wifi options, but it will not connect after clicking connect, nor will it show up in the GUI connection wizard. All LEDs on the cyton and wifi board indicate that it should be working as normal. This comes after several successful uses, and we have not been able to find a solution otherwise.

on open pins (not connected to anything), Is this signal normal?

Goldenhawk — Sat, 14 Jan 2023 02:48:46 +0000

I am seeing very odd noises from my cyton+daisy+wifi module when nothing is connected. Is this normal?
I tried both wifi station and wifi direct, it doesn't make any difference

Gerber files for Wifi Shield?

pluto — Tue, 13 Sep 2022 06:19:39 +0000

Hi @wjcroft,

Can you help in providing the gerber files for Wi-Fi Shield, as we could not find it in the Github repository (https://github.com/OpenBCI/V3_Hardware_Design_Files) ?

Thanks,
Pluto

Mqtt 'Route Not Found'

tjthales — Wed, 31 Aug 2022 06:40:28 +0000

Hi,
I got the wifi shield running firmware version 2.05 with a Cyton board running v3.1.2. It's working like expected, but I can't get mqtt to work. The route /mqtt says: Route Not Found. I'm not sure what I'm doing wrong. I vaguely remember reading somewhere online there's a command to turn mqtt on or off, but I can't find it anywhere in the docs.
Thank you,
Tije

wifi.sendStringLast() and printAll

msl052 — Wed, 31 Aug 2022 17:18:27 +0000

Hello. I am using a custom wifi cyton board and I want to see the wifi.sendStringLast() or printAll() message in the cyton library firmware. I am not able to see it in the console. Is there a way for me to see this properly?

You can find an example of the usage of these functions in OpenBCI_32bit_Library::processIncomingLeadOffSettings() of OpenBCI_32bit_Library.cpp from OpenBCI_32bit_Library.

If anyone have a good lead, then please let me know. That will help out a lot!

WIFI shield and MQTT?

Peter_Gamma — Tue, 19 Jul 2022 09:09:04 +0000

The WIFI shield has MQTT support. The WIFI shield is currently not available from the OpenBCI store.

https://openbci.com/forum/index.php?p=/discussion/comment/17661#Comment_17661

To make the old WIFI shield work properly, it needs as far as we know some soldering and programing skills:

“IMPORTANT NOTE: This product is in beta mode. The WiFi shield is known to have reliability issues (packet loss and cyclical noise spikes) when used with Cyton and CytonDaisy boards. Using it effectively requires advanced technical skills and programming knowledge. Please proceed at your own risk. OpenBCI cannot guarantee that the device will work with your configuration.»

This info can be found somewhere about the OpenBCI WIFI shield, we don t remember where.

If someone is interested in OpenBCI and MQTT and has soldering and programing skills, it would be highly desirable to take over this project and make the WIFI shield resurrect with it s great potential to stream over MQTT.

Options for Cyton/Daisy Sampling Rate

jctaylor — Thu, 14 Apr 2022 14:41:57 +0000

Hello,
As I understand things from previous forum posts, the Cyton samples at a fixed 250 Hz +/- a teeny error. If I plug the Daisy in, it drops to 125 Hz +/-.
Yet, on the OpenBCI Shop website, it states "However, if you select the "save data to microSD card" option in the OpenBCI GUI, you can take advantage of the 250 Hz sampling rate." This suggests that there is some way to boost the Cyton+Daisy sampling rate to 250Hz.
I am not using the OpenBCI GUI, as I need to incorporate markers for ERP into my stream. So I am using the Lab Streaming Layer. Is there a way to get the sampling rate up to 250Hz in the LSL. Alternatively, is there a way to use some other software that accepts markers to work at a 250Hz sample rate (and be exportable to EEGLab.
Would love for WifiShield to come back. But in the meantime, what are my options?
Thank you
Jamie

WiFi shield and MATLAB

TMKii — Wed, 02 Mar 2022 20:02:26 +0000

Hello.
Is it possible to listen data from CYTON+WiFi shield in MATLAB without using OpenBCI GUI?
If it is possible,
can you share any example of Matlab code how can I do this?

WiFi Shield availablity in store? (need higher sample rate)

Dilemma — Wed, 16 Sep 2020 03:44:23 +0000

Seems that the WiFi shield is not available in the OpenBCI store right now. Is there any way to purchase it? Thanks.

sample lossage with the wifi shield at 1000 Hz

Dreambuild — Sat, 12 Jun 2021 09:41:01 +0000

Was using the wifi shield to transfer data to my laptop, but there is constant samples lost. Each sample lost will cause some spike in the LLT and the green light on the wifi shield will blinks as the sample lost happened. Any suggestions to solve this?

How do we change the sampling frequency of the WiFi board?

ngeorge — Wed, 19 May 2021 20:28:48 +0000

I assume this has something to do with editing the .ino file and building the .bat file from the github repo (https://github.com/OpenBCI/OpenBCI_WIFI), but haven't figured it out. Can someone provide instructions for changing the sampling frequency for the WiFi shield? I want to use the maximum sampling rate possible (16kHz I think).

I can figure out the build part, but I can't figure out what setting or line of code needs to go in the .ino file to change the sampling frequency. Perhaps this needs to be done on the Cyton board + Daisy that I'm using anyway, and not the WiFi. I'm not really sure (I don't know how to change the sampling frequency on Cyton either besides doing it through the live arduino connection).

OPENBCI_GUI+cyton+wifi_shield :data stream interrupt

TZR — Sat, 08 May 2021 10:04:03 +0000

When I use openbcigui to connect to the cyton + WiFi board, the data flow often stops. Sometimes it takes three or four seconds, sometimes it takes three or four minutes. The WiFi connection mode is binding route. Because I need the Internet, I don't choose WiFi direct connection. At the same time, the code that I found on GitHub to connect WiFi through brainflow to send the LSL protocol also has this problem

a "stopped streaming" issue using WIFI shield programme

Henryw97 — Wed, 17 Mar 2021 02:55:15 +0000

I tried to connect the OpenBCI devices using Python code and found that “ stream stopped”.
It works on OpenBCI_GUI after all settings done (at least it could print and show all EEG wave images) which means all versions are latest (at least satisfied to run the programme). So I guess the device has already connected to the WIFI. However, after installing all requested packages (numpy, pyOpenBCI, ……) I found that the EXAMPLE.py file didn’t work as it showed “Stopping streaming…Stream stopped WARNING:……”. I still have no idea to figure out this issue after reading many tutorial resources so that I really want you to help me.
The GUI output, Python example code and its output screenshots are attached.

Cheers,
Henry

data format of http response used by Wifi Shield ?

ayushmh — Wed, 16 Dec 2020 08:47:21 +0000

developing my own hardware using esp32 instead of esp8266, I am having issues in sending the EEG signal data to openBCI GUI through wifi. Can anyone please let me know the data format of http response of the wifi shield which is sent to openBCI GUI.
or any other way to stream the data through a third party hardware on the openBCI GUI through wifi.

measured shield regulated 3.3V supply, has .6V dip at 1 second intervals, with resonant ringing

alwayswearshats — Tue, 30 Apr 2019 04:51:18 +0000

Hello,

I have been using my Cyton + WiFi Shield with success but I have noticed that there is an audible (5 kHz+) noise coming from the WiFi Shield. I am powering both boards with a 3.7V Li-ion battery. If I disconnect the Cyton, the audible noise is still present with the WiFi Shield alone.

To further investigate, I used my adjustable DC power supply (Agilent E3620A) with the WiFi Shield on its own, probing the Vbatt+ (directly across the power supply) with my scope.

With the WiFi Shield powered ON, there is a 10 Hz (1 ms duration) pulse that causes my supply voltage to pull down by 200 mV. I think this is some kind of beacon pulse put out by the ESP8266.

With the supply set at 3.50V, there was no audible noise, but as I increased this to 3.75V, I began to hear it and noticeable ringing appeared in the supply trace on my scope. Increasing further caused ringing to get larger in magnitude and appear before, during, and/or after the pulse. Once the supply voltage reached 5.25V, the noise was no longer audible, but there was still some ringing in the scope trace.

Here are scope screenshots with 0.25V increments in the supply voltage:

https://imgur.com/a/y8XE5nc

For the heck of it, I placed a 470uF capacitor across the supply and it did reduce the magnitude of the voltage droop slightly, but it didn't lessen the resonant ringing observed without it.

Wondering if anyone has come across this or has any suggestions on how to suppress the ringing.

Thank you

Wifi shield: channels 9-16 all giving 0uV [resolved]

buzz — Tue, 16 Jun 2020 23:54:33 +0000

Hello, I am new to Cyton+Daisy+ Wifi shield. I found my channel 9-16 gave 0uV reading and zero impedance. The Cyton+Daisy+dongle configuration works fine, which indicates wifi shield causes the trouble. Any diagnosis or suggestions? Thank you very much for your help!
all the best,

Cyton Wifi Streaming data not consistent

gerardkleelab — Tue, 16 Jun 2020 06:50:20 +0000

Hello,
I am working with OpenBCI Cyton with wifi for my research and data streaming started popping here and there. What I mean by popping is that streaming stops, goes, stops, goes and this repeats (the interval between stop and go is really short, though). Are there any ways to fix this issue or ensure that the connection is really good?
I'd appreciate any advice.

Getting data from wifi in raw format when it is set to json

tomas_v — Tue, 07 Apr 2020 18:38:48 +0000

Hello,
I am writing an app in javascript and I am trying to get data from cyton with a wifi shield.
I have a tcp socket server running, I send POST request with output set to json. The response contains connected: true and output: 'json' so it seems all is set up correctly.
Then I start the streaming and I am getting data as follows:

So it seem it is coming in the raw format.

Don't you know what should be done to get data in the JSON format? Thanks

cyton firmware: 3.1.2
wifi shield firmware: 2.0.4

Testing Wifi Shield to transfer data, without Ganglion or Cyton

hahafael — Fri, 03 Apr 2020 21:51:00 +0000

Hi everyone. I would like to know if it's possible to test the wifi shield funcionality to transfer data to open BCI without the ganglion or cyton.
Thank you.

Disable WiFi to remove all EMI

rick123 — Tue, 11 Feb 2020 11:50:26 +0000

Hi,
we need to ensure there are no EMI interference/emissions in the lab. Once we configure the Cyton to uSD is it possible to completely disable the wireless?
Thank you
Rick

Artifact pattern on WiFi Shield + Cyton [resolved]

Strikeroot — Thu, 06 Feb 2020 01:26:38 +0000

Recurring artifact pattern on WiFi Shield + Cyton. Happens whether powering WiFi Shield with 6V AA battery pack or 3.7V LiPo. Happens regardless of sample rate (250, 500, 1000). Does not happen when using bluetooth without WiFi shield.

instructions for updating firmware on WiFi Shield [resolved]

Strikeroot — Wed, 05 Feb 2020 18:54:12 +0000

Could someone please point me to the instructions for how to update the WiFi shield's firmware? I've looked at the readme in GitHub, and while I see many commands and examples, it's not clear to me that that those are the actual firmware update instructions.

Most reliable WiFi Shield configuration?

Strikeroot — Wed, 29 Jan 2020 09:31:33 +0000

I'm trying to get a higher sample rate than the Cyton provides. WiFi shield can purportedly raise this limit but is very buggy, with, in my experience, great difficulty successfully initializing sessions among other issues, as the purchase page states:

IMPORTANT: the WiFi shield is known to have reliability issues (cyclical noise spikes and dropped data packets) when paired with Cyton and CytonDaisy boards.

Question 1) Does this mean the WiFi shield is much more reliable when paired with Ganglion? (i.e. No cyclical noise spikes or dropped data packets.) I don't mind sacrificing channels if this is the case.

Question 2) I've also been told that some of the issues with the WiFi Shield can be resolved by avoiding the 3.7V LiPo battery and instead using one, or even two, AA battery packs.

Can't open WIFI shield PCB [solved]

xsept — Thu, 14 Nov 2019 18:58:12 +0000

Hi,
I have downloaded repo and I trying to open PCB, but it doesn`t open properly.
Last commit from here:
https://github.com/OpenBCI/OpenBCI_Wifi_Shield
I using KiCad 4.0.5

What I doing wrong?
Also when I trying to open schemas, I see errors:
Libraries not found:
\Users\aj\kicad\libraries\kicad-openbci\OpenBCI
\Users\aj\kicad\libraries\kicad-ESP8266\ESP8266
Is it related?

Actually my goal is to generate gerbers, maybe somebody can share gerber files?

Thank you!

No data from WIFI shield + Cyton after starting session

jake — Wed, 08 Jan 2020 20:03:47 +0000

Hello,
I was able to connect to the WIFI shield (Direct mode). I then clicked "Start Session" and it said everything was ready to go. However, when I clicked "Start Data Stream," there was no data sent to the GUI or the output text file.
For the Cyton board, should it be in the PC position? I've tried all combinations and it will connect but there will be no data.

Here is the output of OpenBCI GUI:

Console Log Started at Local Time: 2020-01-08_10-00-15
Screen Resolution: 1920 X 1080
Welcome to the Processing-based OpenBCI GUI!
For more information, please visit: https://openbci.github.io/Documentation/docs/06Software/01-OpenBCISoftware/GUIDocs
Launching application from local data dir
OpenBCI_GUI: hubStart: OS Detected: Linux
TopNav: Internet Connection Successful
Local Version: 417, Latest Version: 417
GUI is up to date!
OpenBCI_GUI::Setup: Is RX mulitcast: false
OpenBCI_GUI::Setup: Has RX joined multicast: false
OpenBCI_GUI::Setup: Sample Data exists in Documents folder.
ControlP5 2.2.6 infos, comments, questions at http://www.sojamo.de/libraries/controlP5
The file "/home/martin/Documents/OpenBCI_GUI/Settings/UserPlaybackHistory.json" is missing or inaccessible, make sure the URL is valid or that the file has been added to your sketch and is readable.
OpenBCI_GUI::Control Panel: Playback history file not found or other error.
OpenBCI_GUI::Setup: Setup is complete!
Instantiating hub object...
Hub: CheckHubInit: The GUI is connected to the Hub!
sourceList: click! 
setInterface: curInterface: -1
channel count set to 8
Setting Latency to 10000
Setting WiFi Internet Protocol to udpBurst
Setting WiFi style to dynamic
[DEFAULT]: Protocol Wifi Selected for Cyton
setInterface: curInterface: 2
Setting sample rate for Cyton to 1000Hz

sample rate set to: 1000
[DEFAULT]: Transfer Protocol set to wifi
Setting WiFi style to static
[INFO]: Using Static IP address of the WiFi Shield!
CP: WiFi IP: Using Static IP address of the WiFi Shield!
Settings: LogFileMaxDuration = 60 minutes
Static IP address of 192.168.4.1
initButtonPressed: Calling initSystem()


=================================================
||             INITIALIZING SYSTEM             ||
=================================================

OpenBCI_GUI: hub : Sent connect to Hub - Id: 192.168.4.1 SampleRate: 1000Hz Latency: 10000ms
InitSettings: Saving Default Settings to file!
SoftwareSettings: 3 active widgets saved!
LoadGUISettings: Applied Widget 0 to Container 4
LoadGUISettings: Applied Widget 2 to Container 9
LoadGUISettings: Applied Widget 11 to Container 3
Hub: sendCommand(String): sending '/0'
Cyton: setBoardMode to :DEFAULT
LoadGUISettings: Expert Mode Off
Hub: processCommand: success -- 9358
Networking: Protocol mode set to Serial
Networking Data Types || show num dropdowns = 13
Apply Serial Networking Mode
Ch 0, Not Active, x24, Normal, Dont Include, Off, Off
Ch 1, Active, x24, Normal, Include, On, Off
InitSettings: /home/martin/Documents/OpenBCI_GUI/Settings/CytonUserSettings.json not found or other error.
SoftwareSettings: Removed old/broken settings file.
[DEFAULT]: The new data source is LIVE (from Cyton  ) and NCHAN = [8]. User Settings Error: Default Settings Loaded.
[DEFAULT]: Attempting to establish a connection with your OpenBCI Board...
Hub: processConnect: made it -- 9855 code: 200
Hub: setBoardType(): sending cyton -- 9856
Hub: processBoardType: success -- 9856
[SUCCESS]: The GUI is done initializing. Settings Loaded! Press "Start Data Stream" to start streaming! --  Cyton firmware v3.1.2
[DEFAULT]: Data stream started.
Cyton: startDataTransfer(): writing 'b' to the wifi shield...
Hub: sendCommand(char): sending 'b'
OpenBCI_GUI: openNewLogFile: opened ODF output file: /home/martin/Documents/OpenBCI_GUI/Recordings/OpenBCISession_2020-01-08_10-00-16/OpenBCI-RAW-2020-01-08_10-00-26.txt
Hub: processCommand: success -- 11303

spikes & railed signals

ncnaret — Thu, 02 Jan 2020 12:06:47 +0000

Hi,
1. when I stack Cyton+Wifi+Daisy, I get spikes in regular intervals. It looks something like that:
https://imgur.com/a/pjJuWwQ
At first I thought there might be some source of interference, but I've tried it at different locations at different times and yet I saw these spikes. At some point I've realized the intervals get way shorter when the batteries are newly charged, intervals of < 3s. (Yes, I only use the provided battery holder with 4 x 1.2V chargeable batteries).

2.
after a while, the signals get often "RAILED", I don't even have a cap connected (only the y-cable is attached):
https://imgur.com/a/TFqg7un
I've been reading in some posts of this forum, that the "RAILED" signals should disappear after a while, but for me they rather appear. If I wait for like 5min, they sometimes disappear e.g.:
https://imgur.com/a/C3Wv9OR (yet you still see these spikes on some channels).
Yet, sometimes the "RAILED" signals appear again.
Is there anything I can do to un-RAIL these? or to prevent these to appear in the first place? What is the reason for this "RAIL".

I've tried to run without the WIFI-board, only Cyton+Daisy (via the COM emulation dongle). I don't have these spikes, yet the same "RAILED" behaviour. I've written my own software (for COM and UDP captures) and in both cases I get signals that are 0xff on many (if not all) channels. In my first (and only) run wearing the cap, I didn't have the "RAILED" issue, but I got weird signals:
https://imgur.com/a/AbJlNRz

Nowadays I get all channels "RAILED" when I try to connect the cap. I've tried to only connect "REF" and "BIAS", to ground the device, in this case it takes some time, but after a while all channels still end up "RAILED".

(Sorry if these questions sound very "beginner"; I'm a software engineer, no real electronics or medic-research experience, this is my first experience with EEG. All I've done (connecting the boards, cap cleaning, etc.) is based on the "Documentation"-area, but that's already where I've reached my limits of resolving these issues myself. I've contacted the mail support before, but they said I might get better answers asking here.)

Cyton not detected when connected to WiFi Shield

Strikeroot — Thu, 10 Oct 2019 01:51:39 +0000

Cyton isn't detected when connected to WiFi Shield. Every other query of the WiFi shield works fine, except for OPENBCI BOARD, which returns 'NONE'. And so of course a session can't be started.
The battery is plugged into the WiFi Shield, which has three blue LEDs on. The blue LED on Cyton is also on. No battery is plugged into Cyton.
Cyton works fine via bluetooth dongle when not connected to Wifi shield and has firmware 3.1.1. WiFi shield has latest firmware.
Grateful for any help.

Cyton Impedance commands not working through Wifi shield API [resolved]

drivas — Mon, 09 Sep 2019 21:29:43 +0000

Hi!

There seems to be a strange behavior when using the endpoint command/ and sending a impedance command such as "z101Z" during streaming with the WiFi shield. I receive a confirmation message from the server running on the shield: Success: Lead off set for 1, but in fact, the signal is left unchanged, and it seems the board simply performs a reset (stopping the resuming streaming immediately).

Cyton board: 32bit, firmware 3.1.2
WiFi shield: firmware 2.0.5
Daisy: yes

This happens no matter the connection parameters, (1 or 2ms latency), on 250Hz or 500Hz (1000Hz not attempted), and on TCP (UDP not attempted). Passing other commands have the expected outcome but sometime make the board "crash":

"V" works as expected and returns the correct firmware
"d" works as expected
test signals work as expected
sample rate setting works as expected
"a" crashes the board
"v" crashes the board
others not attempted

The cyton and daisy board we have work as expected over Bluetooth (as seen using the openBCI_GUI), including the impedance check, so it does not seem they are at fault. The impedance commands fail to have their intended effect whether sent through our Python code or via Postman.

All of this was tested using a custom Python-backed GUI that we have designed for our needs (based on fixes and modifications on your pyOpenBci), and the impedance commands work through bluetooth with our software too. I am unable to test the impedance commands with WiFi through your GUI since it has never succeeded in connecting, see: https://github.com/OpenBCI/OpenBCI_GUI/issues/590

The fact that the shield explicitly reports a success is the most puzzling part for us. As I understand, this message is generated on the Cyton itself so it cannot be a failure to transmit the message from shield to Cyton. Could there be an issue with the Cyton firmware code around https://github.com/OpenBCI/OpenBCI_Cyton_Library/blob/e601937cead66794231d4a9720672aa9f32e18c2/OpenBCI_32bit_Library.cpp#L1294 ?

We are approaching our data collection phase and impedance measurements are important to ensure data quality, any help would be greatly appreciated

Thanks,
Daniel