Search found 1026 matches

by Coen
Mon Oct 18, 2021 2:43 pm
Forum: BioSemi Software (ActiView executable)
Topic: ActiView responding to keyboard commands even when it does not have focus
Replies: 1
Views: 52

Re: ActiView responding to keyboard commands even when it does not have focus

In the latest 9.00 Windows version of ActiView (put on our website today), I have deleted the arrow Left/Right/Up/Down and Pgup/Pgdn keyboard shortcuts. In LabVIEW 2021, the "key focus" property node does not work for the Menu Ring controls, and therefore I could not get the shortcuts to work fully ...
by Coen
Thu Sep 30, 2021 12:49 pm
Forum: BioSemi Software (LabVIEW programming)
Topic: Correct way to index AUX channels?
Replies: 1
Views: 227

Re: Correct way to index AUX channels?

The senso signals are sent from the AD-box in a block of 16 channels. Installed sensors generate data on dedicated channels in the block, uninstalled sensors generate flatliners. ActiView processes the 16 channels into 7 sensor channels (displayed and saved to BDF file). Inspect the LabVIEW source c...
by Coen
Fri Sep 24, 2021 11:44 am
Forum: BioSemi Hardware
Topic: CM out of range with more than 64 electrodes
Replies: 3
Views: 347

Re: CM out of range with more than 64 electrodes

We do not offer a daisy chain option for two 64 channel systems on the same subject.

Best regards, Coen (BioSemi)
by Coen
Wed Sep 22, 2021 9:00 pm
Forum: BioSemi Hardware
Topic: CM out of range with more than 64 electrodes
Replies: 3
Views: 347

Re: CM out of range with more than 64 electrodes

You can only use the channels that are actually installed in the AD-box. To check: inspect the offsets with no electrodes connected to the AD-box, installed channels are maximally negative, uninstalled channels are zero. You will probably find that only channels 1-64 are installed. In order to use m...
by Coen
Wed Sep 22, 2021 8:58 pm
Forum: BioSemi Hardware
Topic: Combing 10-20 and ABCD electrodes for recording 128 electrodes
Replies: 2
Views: 275

Re: Combing 10-20 and ABCD electrodes for recording 128 electrodes

You can only use the channels that are actually installed in the AD-box. To check: inspect the offsets with no electrodes connected to the AD-box, installed channels are maximally negative, uninstalled channels are zero. You will probably find that only channels 1-64 are installed. In order to use m...
by Coen
Mon Sep 20, 2021 1:02 pm
Forum: BioSemi Software (ActiView executable)
Topic: the unit of EMG data
Replies: 1
Views: 288

Re: the unit of EMG data

The scaling of each channel is found in the BDF header, see https://www.biosemi.com/faq/file_format.htm (physical and digital min/max values). The electrode channels are LSB = 31.25 nV (1/32 uV). The scaling in ActiView does not affect the BDF file. All settings in the left sidebar only affect the d...
by Coen
Mon Sep 13, 2021 2:17 pm
Forum: BioSemi Hardware
Topic: Weird noise
Replies: 4
Views: 458

Re: Weird noise

Determine the frequency of the interference (zoom in, make spectrum), it looks like 50 Hz from the mains supply. Test with electrodes in water. Increase/decrease the area of the included loop between cables of CMS/DRL and other electrodes to determine whether an electric or magnetic field causes the...
by Coen
Sun Sep 12, 2021 9:42 pm
Forum: BioSemi Hardware
Topic: Weird noise
Replies: 4
Views: 458

Re: Weird noise

Gel bridge between CMS and DRL, see viewtopic.php?f=7&t=810&p=3048

Best regards, Coen (BioSemi)
by Coen
Fri Aug 27, 2021 12:08 pm
Forum: EEG data analysis
Topic: Biosemi data format/Reading .bdf into Matlab
Replies: 9
Views: 19110

Re: Biosemi data format/Reading .bdf into Matlab

Use the digital and physical min/max values in the file header to scale the data, see https://www.biosemi.com/faq/file_format.htm . From the file header, you can conclude that the scaling for the EEG channels is LSB = 31.25 nV (1/32th uV) Using the BDF --> EDF converter to rescale the data is possib...
by Coen
Thu Aug 19, 2021 12:38 pm
Forum: BioSemi Hardware
Topic: Battery Life
Replies: 1
Views: 580

Re: Battery Life

A 64 channel system should work more than 12 hours on a new battery, and still more than 6 hours on a battery that is a few years old. 2.5 hours is certainly too short, you should replace the internal cells of the battery.

Best regards, Coen (BioSemi)
by Coen
Mon Aug 16, 2021 1:26 pm
Forum: BioSemi Software (ActiView executable)
Topic: Defining in code the number of channels
Replies: 2
Views: 583

Re: Defining in code the number of channels

The above is in principle possible by modifying the (open source LabVIEW) code of ActiView.

Note that you can save the settings (including TCP/IP selections) in the CFG file.

Best regards, Coen (BioSemi)
by Coen
Mon Jul 26, 2021 2:02 pm
Forum: BioSemi Software (ActiView executable)
Topic: ActiView example client raw data transformation
Replies: 2
Views: 736

Re: ActiView example client raw data transformation

Each sample is a 24-bit word from the Analog-to Digital converter. Each 24-bit sample is sent as 3 bytes.

TCP blocksize is in samples
Buffersize is in bytes

Best regards, Coen (BioSemi)
by Coen
Thu Jun 24, 2021 1:26 pm
Forum: BioSemi all other topics
Topic: Synchronizing EEG signal with EMG and speech
Replies: 2
Views: 995

Re: Synchronizing EEG signal with EMG and speech

The ActiveTwo system can measure EEG, EMG (with flat electrodes and headbox, see https://www.biosemi.com/accessoires.htm) and microphone (via ERGO input), all simultaneous, synchronized and up to 16 kHz sample rate. Trying to use other devices for EMG and sound acquisition seems a needless complicat...
by Coen
Wed Jun 16, 2021 5:29 pm
Forum: EEG data analysis
Topic: 1Hz Unexpected Frequency in Signal
Replies: 1
Views: 928

Re: 1Hz Unexpected Frequency in Signal

"Is it possible that something in the hardware is causing this?"

No, the BioSemi system does not generate any signal of exactly 1 Hz.

Best regards, Coen (BioSemi)
by Coen
Thu Jun 10, 2021 3:27 pm
Forum: BioSemi all other topics
Topic: Strange activity on a single electrode
Replies: 11
Views: 17425

Re: Strange activity on a single electrode

You should indeed first remove the flat/bad channels, and then reference to one or more of the remaining valid channels.

Best regards, Coen (BioSemi)
by Coen
Fri May 07, 2021 11:54 am
Forum: BioSemi Hardware
Topic: Is this the problem of battery?
Replies: 3
Views: 1475

Re: Is this the problem of battery?

You probably left the batteries too long (several months) is a discharged state. Always charge the batteries before storing and recharge them every few months. The cells can sometimes be recovered with a few charge/discharge cycles. If not, then contact your local BioSemi representative for replacem...
by Coen
Thu May 06, 2021 11:59 am
Forum: BioSemi Hardware
Topic: Is this the problem of battery?
Replies: 3
Views: 1475

Re: Is this the problem of battery?

Does the second battery work ?

Check the fuse of the battery. If OK, then replace the internal cells.

Best regards, Coen (BioSemi)
by Coen
Tue Mar 16, 2021 12:50 pm
Forum: BioSemi Software (ActiView executable)
Topic: strange event names of triggers on Actiview
Replies: 5
Views: 2306

Re: strange event names of triggers on Actiview

In analog trigger display mode, you see 16 colored dots/bars, indicating the separate trigger lines (bits). It will probably show that there is something wrong with bit 8 (grey, 2^7 = 128). You did not follow my recommendation to inspect the bits in analog trigger display mode. I cannot further help...
by Coen
Mon Mar 15, 2021 8:36 pm
Forum: BioSemi Software (ActiView executable)
Topic: strange event names of triggers on Actiview
Replies: 5
Views: 2306

Re: strange event names of triggers on Actiview

Inspect in "analog" trigger display mode to see which trigger lines are faulty.

Best regards, Coen
by Coen
Wed Mar 10, 2021 1:26 pm
Forum: EEG data analysis
Topic: Different event codes (triggers) in EEGLAB
Replies: 1
Views: 1825

Re: Different event codes (triggers) in EEGLAB

- Use the ""analog" display mode to inspect the 16 separate trigger lines.
- Use positive logic: pull all 16 lines low between the triggers.
- To see the same numbers as "decimal" display mode: split the 16 trigger bits in two 8-bit groups.

Best regards, Coen (BioSemi)
by Coen
Thu Mar 04, 2021 6:31 pm
Forum: BioSemi all other topics
Topic: Can I change the sampling rate to 1000Hz?
Replies: 1
Views: 1623

Re: Can I change the sampling rate to 1000Hz?

Only integer divisions or multiples of 2048 Hz are possible. Sample-rate are available in powers of 2 from 32 Hz (speedmode 4, decimation = 1/64) to 16384 Hz (speedmode 7, decimation = 1). Note that the analog bandwidth is always approx. 1/5th of the sample-rate (indicated in the right sidebar). For...
by Coen
Tue Feb 16, 2021 6:03 pm
Forum: BioSemi Software (ActiView executable)
Topic: ActiView: LabView Resource not found
Replies: 3
Views: 2036

Re: ActiView: LabView Resource not found

lvanlys.dll, lvinput.dll and RingBuffer.dll are in the zip download from our website. Make sure that these three dll's are in the same folder (or a subfolder) as the ActiView.exe.

Best regards, Coen (BioSemi)
by Coen
Tue Feb 09, 2021 12:46 pm
Forum: EEG data analysis
Topic: Swapped head side and amp slots
Replies: 3
Views: 2326

Re: Swapped head side and amp slots

Yes
by Coen
Mon Feb 08, 2021 7:07 pm
Forum: EEG data analysis
Topic: Swapped head side and amp slots
Replies: 3
Views: 2326

Re: Swapped head side and amp slots

The B slot does not have the CMS/DRL connections. If you did not use a separate CMS/DRL, then the Common Mode was not in range (blue light blinking) and unfortunately your data is useless (no power to active electrodes).

Best regards, Coen (BioSemi)
by Coen
Fri Feb 05, 2021 12:14 pm
Forum: BioSemi Hardware
Topic: Unknown(and unexcpected) noise
Replies: 1
Views: 2232

Re: Unknown(and unexcpected) noise

Blue light blinking ? Common Mode was not in range, confirm by checking the trigger/status channel in the BDF file. For solutions, see https://www.biosemi.com/faq/check_electrodes.htm . Data measured with blinking blue light is meaningless because power to the active electrodes is cut off. Best rega...
by Coen
Fri Jan 22, 2021 6:58 pm
Forum: BioSemi Hardware
Topic: Triggers with arduino board
Replies: 1
Views: 2007

Re: Triggers with arduino board

Connect the digital outputs of the Arduino to the trigger port of the USB-receiver (pin 1-16 are trigger inputs, pin 37 is ground, see https://www.biosemi.com/faq/trigger_signals.htm ). Both 3.3V and 5V output will work OK.

Best regards, Coen (BioSemi)
by Coen
Tue Jan 19, 2021 2:44 pm
Forum: BioSemi Hardware
Topic: Post hoc measurement of EEG quality
Replies: 3
Views: 2686

Re: Post hoc measurement of EEG quality

Offset is just the average of a few seconds data (or low-passed data with a cut-off frequency < 1 sec) Inject just enough gel to fill the holder, but not more (or you may introduce gel bridges). Use (rotate) the tip of the syringe to gentle work the gel between the hair onto the skin. The electrode ...
by Coen
Thu Jan 07, 2021 10:54 pm
Forum: BioSemi Hardware
Topic: Post hoc measurement of EEG quality
Replies: 3
Views: 2686

Re: Post hoc measurement of EEG quality

Offsets are readily extracted from the data, see http://www.biosemi.nl/forum/viewtopic.php?t=56

Best regards, Coen (BioSemi)
by Coen
Tue Dec 08, 2020 5:55 pm
Forum: BioSemi Software (ActiView executable)
Topic: send ECG data measured by Biosemi to another device.
Replies: 4
Views: 3088

Re: send ECG data measured by Biosemi to another device.

Use the TCP/IP link in ActiView and a client example from https://www.biosemi.com/download.htm (available in LabVIEW or MatLab).

Best regards, Coen (BioSemi)