yj
yj
About
- Username
- yj
- Location
- France , Bordeaux
- Joined
- Visits
- 595
- Last Active
- Roles
- Member
- Location
- France , Bordeaux
- Interests
- Neurosciences
Comments
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Profeell, concerning " improving the sample rate ", V3 or V1 does not make any difference: If you write the data on the SD using the "block mode" one need to write this block betwwen two samples. If your sample rate is 8kHz you have only 1…
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Hello profeell, You write to me: > I want to use WIFI shield to get the data, I am not the best person to answer because I do not know in detail the code of the library of the last version (v3?) which transmits the data acquired by wifi. …
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@yttuncel, Its a fact that I never went back from my code to the previous initial version... Your hypothesis is good, it could be because I used differently the EEPROM... The basic code (there under in blue) supposes that variables fileOnes and …
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@yttuncel, The last 512 bytes block begins by a short ascii message and is filled with zeros. If you do not have zeros (at least 256) at the end , it might be a SD card problem. Try any 8gb SD card ... Some good quality and very fast 16gb cards…
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@yttuncel, I do not have the V2, but someone from the forum or from OBCI project, should be able to quickly tell you if SD writing is ok or not... Can you read the footer at the end ? It should be ascii. y.j.
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@yttuncel, Pushtheworld is right, first of all, ensure yourself that your SD card works. These SD are rather ticklish, I got incredible problems with 16gb using the very same ref, one works the other dont... Have you red : http://docs.openb…
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@yttuncel, The command 'a' generates à 512 blocks file, a block 512 bytes ; 512*512 = 262.144 = 262.128 (last value of your counter) +16 bytes (content of the last line) as you write. Thus it seems correct. You should see at the end of this f…
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@yttuncell , - Do you have aproximately 5 x 60 x 250 lines in the last "not empty" 5' recorded txt file? - What do you get in the *.txt files from the un-modified code? (Some SD cards that perfectly work on your P.C., will not be usable on the …
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Isn't it the case with current connection as well? Yes , "every thing is relative" If we lost raw datas, the values of the new incoming datas are true. After ADCPM "uncompression" the new uncompressed values are no longer reliable. One no longe…
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@yttuncel Hello yttuncel, If you are ready to modify the pic32 code and the pc code (device and host) then you could compress the 16bit data by a factor of 4, using ADPCM : see "Adaptive Differential Pulse Code Modulation Using PIC® Microcontro…
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Hello, @pushtheworld. The setup function in question is well this one? : void setup() { // Declare the radio mode and channel number. Note this channel is only // set the first time the board powers up OR after a flash of the non- // volati…
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@PedroMen, 1) 2kHz is the highest sampling rate one can get without problems. 2) If the sound track of the video is not already used, if you can associate some sounds to the images then you could use the sound card output of the P.C. to…
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@ PedroMen, If you need 500Hz and accept to record on the SD only using the command 'N' then upload the yj-xxxiii. Else use Winslow_Strong version but you will have to build a hardware link. Can you describe a bit what you want to do? (If your pr…
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@pushtheworld, yes, sure, it is not the same code... Nevertheless note that this "new" code could run as well and faster, just looking at the AD_ready signal instead of looking at the flag risen by an interrupt itself triggered by this same AD_r…
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Thank's for the links @PushTheWorld. I have just flew over the v2, and I must confess that I did not fully understand all the improvements. Despite this I have the feeling that it is a wonderfull work and I already feel desire to try to include…
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Hello everybody. What a pleasure it is to read a such news. This wakes me up. Is https://github.com/OpenBCI/OpenBCI_32bit_Library the right link to the new firmware? @pushtheworld : First of all, thanks for that work. Could you briefly co…
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@nhatminh84, Yes , you have to write that and to send an "N" command to start recording. The file FI_7204.bin will be a binary file... To get a *.txt file, more readable , send a single 'B' , it toggles .bin / .txt y.j.
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Hello @nhatminh84, You must send the chars one by one. '.' send "2" send I see that you wrote ".2" in the input window. If you want to send the string ".2" then write +.++2+ and send. (I use windows XP...) What do you mean by "see the 2kH…
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Thank's @biomurph, I imagined/(wondered if) , that this "clock" signal could be "sample rate" dependent and could have forced the Daisy_ADS to follow the rate and sync... So we must write as I already wrote and asked to Winslow_Strong : WREG(CO…
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It is a frequent phenomena which also appends with the Raspberry family. Many low cost 8GB SD work. "Best is the enemy of the good" the 8GB one recommanded by OBCI always worked for us. This said one of our 32bitsV3 suddenly stopped working with a…
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@Winslow_Strong, Have you tested the sample rate change when the Daisy is present? In the library when the daisy is present the bit to enable the clock is set (0x90->B0) in the BOARD_ADS's CONFIG1 register , that's all... Since after the ADS-1…
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@Winslow_Strong, if you have time... I am not sure but try (Sorry , currently I have no available card to test these suggestion modifs) : 1) To not to ignore the Daisy_Board (at least this should be done ) In the function void Open…
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@Winslow_Strong, I had a glance to the code, my memory is bad , the code does more than I wrote in the previous post... I need a time for calm reflection... y.j.
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@Winslow_Strong, Yes, sorry I do not have and use the daisy board. The code does nearly nothing in case of a present Daisy. It's already a chance that it does not completly crashes... Your hardware is OK, that's sure... Do you obtain flat lines …
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@Winslow_Strong, Sorry , I am afraid that you are probably right ! ! ! The boolean "firstDataPacket" is true at start : line 175 & 590 and after that always false... Strange affair... The code seems to do an average at each sampling step…
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@Winslow_Strong, you make me doubt, I was thinking that : at t1= 0mS channels 1-16 are sampled at t2= 4mS channels 1-16 are sampled again average t1,2 ch 1- 8 are sent in frame 1 (odd ) time stamp = 2mS at t3= 8mS channels 1-16…
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@Winslow_Strong, just a note : averages are sent alternatively ( or successively , sequentially, serially, [1:8,9:16], like any bits...) but the 16 channels have been sampled synchronously @ 250Hz. y.j.
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@wjcroft, Thank you very much William for these references to papers (not easy to read, at least for me) and discussion which I discover. The u-Law is not loss less... When the signal increases small details disappear. I wonder how it would af…
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Hello, @Winslow_Strong, Do you realy need 1kHz to performe neurofeedback? Which kind of EEG "high frequency" feature dou you want to use/study? Have you thought about data compression? Most of the time 16bits are enough, then using 16 instead 24…