Unreliable connection to 6DOF v4

Wireless & IoT
1

Hello guys,

I got a 6DOF v4 the other to use for my Master thesis. And after taking the first hurdle of realizing that the batteries needed a charge up it worked fine for some time :wink:

Now I run into the following problem. I believe it’s easier to use the module in binary mode with Matlab (easier to handle the readings), but when I switch to binary mode sooner or later the connection drops and then the module can’t be used for some time.

I can still establish a connection (the red diode lightens up), but even Hypterterminal doesn’t get any response from it. No menu, no readings, nothing. Usually when I leave it for some time (unplugged from the power supply) it works again at some point (but that can’t be how it’s supposed to be)

When the connection drops, the sampling stops as well (if I remember well) and sooner or later the status LEDs start to blink in the form of “all on”, “all off”, “all on”. A mode, which is not talked about in the manual

Any suggestions on this? What I basically want is to have it work reliably in binary mode, 'cause then I wouldn’t have to bother with the String handling and half lines due to overwritten buffer etc.

(It is quite a pain in the ass to use with Matlab anyway, but I can live with that)

Thanks a lot for your comments,

Sandro

2

Hey,

Can you please explain what you meant by, i suppose a fresh battery should be needed for basically everything.

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I got a 6DOF v4 the other to use for my Master thesis. And after taking the first hurdle of realizing that the batteries needed a charge up it worked fine for some time :wink:

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Although, it reads that the bluetooth can go up to 100m, my personal experience with v4 is within range of 10m.

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Now I run into the following problem. I believe it’s easier to use the module in binary mode with Matlab (easier to handle the readings), but when I switch to binary mode sooner or later the connection drops and then the module can’t be used for some time.

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if you are using bluetooth, you need to update your bluetooth drivers (widcomm if you are using broadcom) and you have to ensure that you did select the right port number.

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I can still establish a connection (the red diode lightens up), but even Hypterterminal doesn’t get any response from it. No menu, no readings, nothing. Usually when I leave it for some time (unplugged from the power supply) it works again at some point (but that can’t be how it’s supposed to be)

}}

weird

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When the connection drops, the sampling stops as well (if I remember well) and sooner or later the status LEDs start to blink in the form of “all on”, “all off”, “all on”. A mode, which is not talked about in the manual

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don’t be lazy, either you can write an api for matlab or just use the copy and paste methodology. :slight_smile:

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Any suggestions on this? What I basically want is to have it work reliably in binary mode, 'cause then I wouldn’t have to bother with the String handling and half lines due to overwritten buffer etc.

(It is quite a pain in the ass to use with Matlab anyway, but I can live with that)

}}

3

Thanks for your answer…

Can you please explain what you meant by, i suppose a fresh battery should be needed for basically everything

In the beginning (when I had not yet accomplished to get anything out of the thing) I was not sure what the problem was. It seemed that the batteries were okay, as some LEDs were on. It turned out that the sensor part worked, but the BT module shut itself down due to low battery and that is why it didn’t work. When I realized that I changed batteries and everything was fine…

Although, it reads that the bluetooth can go up to 100m, my personal experience with v4 is within range of 10m.

The sensor is lying on my desk, so it’s at most 1 m away. And also: in ASCII mode it works reliably

If you are using bluetooth, you need to update your bluetooth drivers (widcomm if you are using broadcom) and you have to ensure that you did select the right port number.

Bluetooth drivers are up to date and I have the right port number. After all, it wouldn’t work at all with the wrong one, would it?

I guess I’ll go with the ASCII mode for the moment, but hints on the binary mode stuff would still be greatly appreciated.

One more question about the inputbuffer: I guess it is written to until it is filled and then it starts over from the beginning overwriting the latest data, right? The thing is that when reading from it I don’t always get proper lines of data. Sometimes another line starts in the middle of the first etc. Pretty annoying stuff when you want to extract the data via string manipulation from it. Any suggestions on that?

4

sorry, you are right with regards to this. i notice this too. but you should take note that it drains 150mA (see datasheet and doing some maths, should account you some batt juice accounting).

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In the beginning (when I had not yet accomplished to get anything out of the thing) I was not sure what the problem was. It seemed that the batteries were okay, as some LEDs were on. It turned out that the sensor part worked, but the BT module shut itself down due to low battery and that is why it didn’t work. When I realized that I changed batteries and everything was fine…

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i see, i have not used binary yet, i dont see the need, why do you see binary to be superior for matlab? i am using matlab with ascii

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The sensor is lying on my desk, so it’s at most 1 m away. And also: in ASCII mode it works reliably

which input buffer are you talking about? matlab? i notice that the matlab serial toolbox is crap. you have to enable your port even though it thinks i has, so just check if it is.

yeah, that input buffer issue is a problem. i think flushing should helps.

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One more question about the inputbuffer: I guess it is written to until it is filled and then it starts over from the beginning overwriting the latest data, right? The thing is that when reading from it I don’t always get proper lines of data. Sometimes another line starts in the middle of the first etc. Pretty annoying stuff when you want to extract the data via string manipulation from it. Any suggestions on that?[/quote]

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are you using the gyro idg300, did you realise that the bias is way off? the datasheet of idg300 says that it should be 1.5v +/-.1

but mine is way off,

when i placed the triads’ sensitive axis in the east/west direction, this is what i get

p=448.8922, r=475.9041, y= 425.1369

p= 448.8828, r= 475.8208, y= 425.1369

(i am at down under , so earth rotation should be insignificant)

i then used the dmm to look at the yaw rate output, it reads 1.37v, so if we assume buffering/impedance transfer was done appropriately, so where is the angular rate coming from???