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by drhastings
Thu Nov 05, 2015 9:32 pm
Forum: C/C++
Topic: could not insert module test.ko: Invalid module format
Replies: 1
Views: 830

Re: could not insert module test.ko: Invalid module format

Hi, I think you built against the wrong Modules.symvers, it looks like you built the module to run against the kernel used on the rpi but you are using an rpi2. I think if you download this and replace the Modules.symvers in the base of your source tree with it, then re-build the module it should wo...
by drhastings
Sat Jun 13, 2015 11:15 pm
Forum: General discussion
Topic: Installing Wireshark: "Failed to fetch" errors
Replies: 3
Views: 13833

Re: Installing Wireshark: "Failed to fetch" errors

Have you tried

Code: Select all

sudo apt-get update
first?
by drhastings
Sat May 23, 2015 3:33 pm
Forum: General discussion
Topic: Batch bash command files
Replies: 26
Views: 3442

Re: Batch bash command files

Or you could just call rm. What is the sleep supposed to accomplish?
by drhastings
Fri May 22, 2015 8:21 pm
Forum: General discussion
Topic: Batch bash command files
Replies: 26
Views: 3442

Re: Batch bash command files

Not once have I ever wished that rm had a 5 second delay, but you showed us a way to make removing files more complicated and more time consuming.

I'm not sure if I should laugh or cry.
by drhastings
Thu May 07, 2015 8:45 pm
Forum: Automation, sensing and robotics
Topic: Mapping indoor spaces
Replies: 4
Views: 2995

Re: Mapping indoor spaces

Its the lidar from a Neato xv11 vacuum cleaner, purchased from ebay.

https://xv11hacking.wikispaces.com/LIDAR+Sensor, useful info was found here.
by drhastings
Thu May 07, 2015 8:22 pm
Forum: Automation, sensing and robotics
Topic: Mapping indoor spaces
Replies: 4
Views: 2995

Mapping indoor spaces

Hello, I've been trying to teach a robot how to map indoor spaces and then navigate autonomously. I'm using a 360 degree lidar ranging sensor, wheel encoders and a 6-axis gyro/accel combo for sensors. And of course a raspberry pi 2 to do all the number crunching. I'm starting to get decent results. ...
by drhastings
Sun Apr 26, 2015 3:43 pm
Forum: Off topic discussion
Topic: Programming a TI Launchpad Microcontroller
Replies: 11
Views: 2182

Re: Programming a TI Launchpad Microcontroller

I think you would be more likely to get a useful answer to that question on a different forum.
by drhastings
Tue Jun 17, 2014 6:46 pm
Forum: Automation, sensing and robotics
Topic: An experiment in pointing a sonar ranger at a wall
Replies: 38
Views: 8422

Re: An experiment in pointing a sonar ranger at a wall

Yes, there are other factors, but I think that the factors you listed would be of smaller magnitude than the affect you have shown above. The sensor I'm using only has a single transducer that is used for both sending and receiving which simplifies the situation somewhat and I've observed the same p...
by drhastings
Tue Jun 17, 2014 4:37 pm
Forum: Automation, sensing and robotics
Topic: An experiment in pointing a sonar ranger at a wall
Replies: 38
Views: 8422

Re: An experiment in pointing a sonar ranger at a wall

From my own tests, I think the reason that you aren't getting the closest reading at 0 degrees is because the sonar will pick up a return in a somewhat sizeable volume of space in front of it. Imagine the sonar pointing straight at the wall. You could draw a circle on the wall that represented the a...
by drhastings
Wed Jun 11, 2014 7:59 pm
Forum: Automation, sensing and robotics
Topic: Balancing robot with camera
Replies: 29
Views: 8009

Re: Balancing robot with camera

https://github.com/drhastings/balance, this is pretty up to date and has the blob tracking functionality. Good luck! Things started to sprawl as I neared the end. If you can find a comment, chances are it is incorrect.
by drhastings
Tue May 27, 2014 5:04 pm
Forum: Automation, sensing and robotics
Topic: MPU-9150 Nine-Axis IMU rotation matrix
Replies: 5
Views: 2804

Re: MPU-9150 Nine-Axis IMU rotation matrix

Hi,

Why don't you just generate a matrix from the quaternion?

http://web.archive.org/web/200609142241 ... t.html#Q54
by drhastings
Mon May 12, 2014 4:40 pm
Forum: OpenGLES
Topic: Performant reading of data from GL
Replies: 6
Views: 3969

Re: Performant reading of data from GL

The way I did it was to render to an offscreen buffer, then use that as a texture on a quad that filled the viewport, rendered by three different shader programs. The first shader program converts from RGB to YUV and packs the Y values into an output frame buffer that is (width / 4) * height in size...
by drhastings
Wed May 07, 2014 6:04 pm
Forum: OpenGLES
Topic: Performant reading of data from GL
Replies: 6
Views: 3969

Re: Performant reading of data from GL

Although there is no easy way to encode shaded video, it can be done if you are willing to forgo full resolution. I've managed to feed the output from glReadPixels into the hardware encoder. I'm currently running at [email protected]. I had to write some shaders that split the rgb encoded frames to thre...
by drhastings
Fri Apr 18, 2014 2:18 am
Forum: Interfacing (DSI, CSI, I2C, etc.)
Topic: Fixed address I2C expander (PCA9536D) on a shared bus
Replies: 5
Views: 1333

Re: Fixed address I2C expander (PCA9536D) on a shared bus

i2cdetect uses the userspace i2c interface, i2c-dev. If you want to use this interface you need to un-blacklist it. The sound card is doing its i2c comms in kernelspace and does not depend on the userspace interface so it will work regardless of whether the userspace module is loaded or not as long ...
by drhastings
Fri Apr 11, 2014 5:01 am
Forum: C/C++
Topic: Please Help with my undefined reference problem
Replies: 3
Views: 2940

Re: Please Help with my undefined reference problem

Append -lpigpio to your gcc invocation to link the library.

Code: Select all

gcc -Wall -o Constant -lpigpio Constant.c
by drhastings
Sat Apr 05, 2014 5:23 pm
Forum: Automation, sensing and robotics
Topic: Directional motion detection
Replies: 15
Views: 4436

Re: Directional motion detection

[quote]That's my plan, if I can find a suitable detector - Kalman or simple complementary is enough - I don't think GPS is up to the job regardless of filter type - its 1m resolution means the quad can pick up quite a lot of speed before GPS would recognise the movement, so the quad would overshoot,...
by drhastings
Sat Apr 05, 2014 2:55 pm
Forum: Automation, sensing and robotics
Topic: Directional motion detection
Replies: 15
Views: 4436

Re: Directional motion detection

Kalman filter on the gps and accelerometer data? What rate do you acquire gps coordinates?
by drhastings
Wed Mar 05, 2014 5:48 pm
Forum: Automation, sensing and robotics
Topic: Pi robot can see
Replies: 13
Views: 2848

Re: Pi robot can see

That's impressive. How have you speeded it up? A number of small tweaks and I discovered a bug in the vision pipeline that was basically quartering the sensitivity to the post its. After fixing that bug I found I was just able to up the speed. Most of the factors, ie linear and rotational accelerat...
by drhastings
Wed Mar 05, 2014 3:54 am
Forum: Automation, sensing and robotics
Topic: Pi robot can see
Replies: 13
Views: 2848

Re: Pi robot can see

This seems fast!

Faster than I can drive it by remote and hit the targets that quickly anyway.
by drhastings
Tue Mar 04, 2014 4:31 pm
Forum: Automation, sensing and robotics
Topic: Pi robot can see
Replies: 13
Views: 2848

Re: Pi robot can see

New video from the robots perspective https://www.youtube.com/watch?v=BYAU8YbTF9g.
by drhastings
Tue Mar 04, 2014 12:23 am
Forum: Graphics programming
Topic: Openmax -> OpenGLES Blob tracking demo
Replies: 2
Views: 2778

Re: Openmax -> OpenGLES Blob tracking demo

Pan tilt tracking of a tennis ball from the robots point of view while balancing in place: https://www.youtube.com/watch?v=nUQT2Wj ... e=youtu.be
by drhastings
Mon Mar 03, 2014 8:13 pm
Forum: Graphics programming
Topic: Openmax -> OpenGLES Blob tracking demo
Replies: 2
Views: 2778

Re: Openmax -> OpenGLES Blob tracking demo

So I've made some progress and found some issues with this implemenation. I'm starting from 512x512 and I'm finding that the downsampling to a 1x1 pixel for reading back the result is causing smaller sized blobs to disappear as I can only use 8 bits of precision in each channel and I start losing th...
by drhastings
Thu Feb 27, 2014 10:37 pm
Forum: Automation, sensing and robotics
Topic: Real Time ISR with Quadrature Encoder
Replies: 22
Views: 14746

Re: Real Time ISR with Quadrature Encoder

Are you trying to do this in user space or as a kernel module? I think you can do better than 100us in kernel space although still with potential for jitter when linux turns off interrupts while doing other things like writing to the sd card.

What kind of latency do you need?
by drhastings
Thu Feb 27, 2014 10:05 pm
Forum: Automation, sensing and robotics
Topic: 'Integrating' accelerometer readings to get speed
Replies: 10
Views: 2927

Re: 'Integrating' accelerometer readings to get speed

The problem I'm looking to improve upon is that over time, the 'integrated' accelerometer drifts, probably due to 'integration' errors, so I'm looking at ways to minimize those errors. I may try the simple solution just to see if it helps. Error is a fact of life and once you start integrating sens...

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