I am wondering if it makes sense to fuse multiple GPS signals to improve my estimated result. This works fine for example for accelartion sensors, but this sensors have a white gaussian noise.
GPS sensors being mounted on the same board probably suffer from the same errors like drift or multi-path effects, which cannot be corrected by only fuse the sensor readings of this sensors. I imagine that like a constant offset in the same direction, which won t be correct just stays nearly the same.
Furthermore, I have diffrent sensor which I can mount on my drone, even RKT sensor. In my opinion, it makes no sense to fuse a d-GPS with readings from an RKT GPS.
Please correct my if I am wrong.
Thank you in advance and I hope this forum is the right spot to ask that question.
yes you can. Use EKF based approach with onboard multi GPS and multi IMU
The DJi is doing it, But it is can only prevent one of sensor failure, not the systematic drift patter. To avoid that, you need some more source such as visual odometry or lidar odometry to fuse in the EKF. GPS sate count is good meaure of how bad the position is. It ranges from 0 to 15. So when every one is 15, trust GPS more less variance. When everyone is lower than 6 add very high variance to GPS source.
Yes RTK might be better when you have direct line of sight. But once out of sight, then other GPS might be better. So totaly depends on your use case
I am using SharpDX and am fairly comfortable with it at the moment, but for an assessment for university, I need to create a demo which utilizes some sort of GPU acceleration. This is an 'independent research' task - what that means is, I assigned myself this task. I am legitimately interested in GPU acceleration in games, but right now it feels like I threw myself way too far into the deep.
I am planning to do a particle system (it will be a very BASIC system, with particles firing/falling/dieing) but I need a starting point.
Can someone point me in the right direction? Articles to read? things to consider? I have googled my heart out on things like "GPU acceleration DirectX", but I can't find any solid results! I wish I had a sort of 'hello world' for GPU acceleration..!
If you want to understand how to build a GPU particle system, I suggest you to read the book "Practical Rendering And Compution with Direct3D11", where you will find an entire chapter dedicated on how to implement a simple GPU particle system.
Then the most trickiest part is probably the sorting algorithm which is not detailed in the previous book, but you can have a look at ComputeShaderSort11 sample from the old DirectX June 2010 that could help you a lot (the implementation is quite efficient).
Also, I did a full particle engine on the GPU with SharpDX at my work, so It is perfectly achievable with SharpDX.
I wanted to know what steps one would need to take to "hack" a camera's firmware to add/change features, specifically cameras of Canon or Olympus make.
I can understand this is an involved topic, but a general outline of the steps and what I issues I should keep an eye out for would be appreciated.
I presume the first step is to take the firmware, load it into a decompiler (any recommendations?) and examine the contents. I admit I've never decompiled code before, so this will be a good challenge to get me started, any advice? books? tutorials? what should I expect?
Thanks stack as always!
Note : I know about Magic Lantern and CHDK, I want to get technical advise on how they were started and came to be.
http://magiclantern.wikia.com/wiki/Decompiling
http://magiclantern.wikia.com/wiki/Struct_Guessing
http://magiclantern.wikia.com/wiki/Firmware_file
http://magiclantern.wikia.com/wiki/GUI_Events/550D
http://magiclantern.wikia.com/wiki/Register_Map/Brute_Force
I wanted to know what steps one would need to take to "hack" a
camera's firmware to add/change features, specifically cameras of
Canon or Olympus make.
General steps for this hacking/reverse engineering:
Gathering information about the camera system (main CPU, Image coprocessor, RAM/Flash chips..). Challenges: Camera system makers tend to hide such sensitive information. Also, datasheets/documentation for proprietary chips are not released to public at all.
Getting firmware: through dumping Flash memory inside the camera or extracting the firmware from update packages used for camera firmware update. Challenges: Accessing readout circuitry for flash is not a trivial job specially with the fact that camera systems have one of the most densely populated PCBs. Also, Proprietary firmware are highly protected with sophisticated encryption algorithms when embedded into update packages.
Dis-assembly: getting a "bit" more readable instructions out of the opcode firmware. Challenges: Although dis-assemblers are widely available, they will give you the "operational" equivalent assembly code out of the opcode with no guarantee for being human readable/meaningful.
Customization: Just after understanding most of the code functionalities, you can make modifications that need not to harm normal operation of the camera system. Challenges: Not an easy task.
Alternatively, I highly recommend you to look for an already open source camera software (also HW). You can learn a lot about camera systems.
Such projects are: Elphel and AXIOM
I am right now working on one application where I need to find out user's heartbeat rate. I found plenty of applications working on the same. But not able to find a single private or public API supporting the same.
Is there any framework available, that can be helpful for the same? Also I was wondering whether UIAccelerometer class can be helpful for the same and what can be the level of accuracy with the same?
How to implement the same feature using : putting the finger on iPhone camera or by putting the microphones on jaw or wrist or some other way?
Is there any way to check the blood circulation changes ad find the heart beat using the same or UIAccelerometer? Any API or some code?? Thank you.
There is no API used to detect heart rates, these apps do so in a variety of ways.
Some will use the accelerometer to measure when the device shakes with each pulse. Other use the camera lens, with the flash on, then detect when blood moves through the finger by detecting the light levels that can be seen.
Various DSP signal processing techniques can be used to possibly discern very low level periodic signals out of a long enough set of samples taken at an appropriate sample rate (accelerometer or reflected light color).
Some of the advanced math functions in the Accelerate framework API can be used as building blocks for these various DSP techniques. An explanation would require several chapters of a Digital Signal Processing textbook, so that might be a good place to start.
I'd like to start messing around programming and building something with an Arduino board, but I can't think of any great ideas on what to build. Do you have any suggestions?
I show kids, who have never programmed, or done any electronics before, to make a simple 'Phototrope', a light sensitive robot, in about a day. It costs under £30 (GBP) including Arduino, electronics and off-the-shelf mechanics. If folks really get into mobile robots, the initial project can grow and grow (which I feel is part of the fun).
There are international robot competitions which require relatively simple mechanics to get started, e.g. in the UK http://www.tic.ac.uk/micromouse/toh.asp
Ultimate performance require specially built machines (for lightness) , but folks would get creditable results with an Arduino Nano, the right electronics, and a couple of good motors.
A line following robot is the classic mobile robot project. The track can be as simple as electrical tape. Pololu have some fun videos about their near-Arduino 3PI robot. The sensors are about £1, and there are a bunch of simple motor+gearbox kits from lots of places for under £10. Add a few £ for motor control, and you have autonomous robot mechanics, in need of programming! Add an Infrared Remote receiver (about £1), and you can drive it around using your TV remote. Add a small solar cell, use an Arduino analogue input to measure voltage, and it can find the sun. With a bit more electronics, it can 'feed' itself. And so it gets more sophisticated. Each step might be no more than a few hours to a few days effort, and you'll find new problems to solve and learn from.
IMHO, the most interesting (low-cost) competitions are maze solving robots. The international competition rule require the robot to explore a walled maze, usually using Infrared sensors, and calculate their optimal route. The challenges include keeping track of current position to near-millimeter accuracy, dealing with real world's unpredictably noisy environment and optimising straight-line speed with shortest distance cornering.
All that in 16K of program, and 1K RAM, with real-time interrupt handling (as much as 100K interrupts/second for some motor systems), sensor sampling, motor speed control, and maze solving is an interesting programming challenge. (You might make it 'easy' with 32K of program, and 2K RAM :-)
I'm working on a 'constrained' robot challenge (based on Arduino) so that robot performance is mainly about programming rather than having a big budget.
Start small and build up to something more complex. Control servos. Blink LEDs. Debounce inputs. Read analog sensors. Display text on an LCD. Then put it together.
Despite the name, I like the "Evil Genius" book for PIC microcontrollers because of the small, easily digestible projects that tend to build on one another. It is, of course, aimed at PIC programmers rather than the Arduino, but the material covered will be useful no matter what you're developing on.
I know Arduino is trendy right now, but I also like the Teensy++ development board because of its low price-point ($24), breadboard-compatible PCB, relatively high pin count, Linux development environment, USB connectivity, and not needing a programmer. Worth considering for smaller projects.
If you come up with something cool, let me know. I need an excuse to do something fun :)
Bicycle-related ideas:
theft alarm (perhaps with radio link to a base station which is connected to a PC by Ethernet)
fancy trip computer (with reed switch or opto sensor on wheel)
integrate with a GPS telematics unit (trip logging) with Ethernet/USB download of logged data to PC. Also has an interesting PC programming component--integrate with Google Maps.
Other ideas:
Clock with automatic time sync from:
GPS receiver
FM radio signal with embedded RDS data with CT code
Digital radio (DAB+)
Mobile phone tower (would it require a subscription and SIM card for this receive-only operation?)
NTP server via:
Ethernet
WiFi
ZigBee (with a ZigBee coordinator that gets its time from e.g. Ethernet or GPS)
Mains electricity smart meter via ZigBee (I'm interested now that smart meters are being introduced in Victoria, Australia; not sure if the smart meters broadcast the time info though, and whether it requires authentication)
Metronome
Instrument tuner
This reverse-geocache puzzle box was an awesome Arduino project. You could take this to the next step, e.g. have a reverse-geocache box that gives out a clue only at a specific location, and then using physical clues found at that location coupled with the next clue from the box, determine where to go for the next step.
You could do one of the firefighting robot competitions. We built a robot in university for my bachelor's final project, but didn't have time to enter the competition. Plus the robot needed some polish anyway... :)
Video here.
Mind you, this was done with a Motorola HC12 and a C compiler, and most components outside the microcontroller board were made from scratch, so it took longer than it should. Should be much easier with prefab components.
Path finding/obstacle navigation is typically a good project to start with. If you want something practical, take a look at how iRobot vacuums the floor and come up with a better scheme.
Depends on your background and if you want practical or cool. On the practical side, a remote control could be a simple starting point. It's got buttons and lights but isn't too demanding.
For a cool project maybe a Simon-style memory game or anything with lights & noises (thinking theremin-style).
I don't have suggestions or perhaps something like a line follower robot. I could help you with some links for inspiration
Arduino tutorials
Top 40 Arduino Projects of the Web
20 Unbelievable Arduino Projects
I'm currently developing plans to automate my 30 year old model train layout.
A POV device could be fun to build (just google for POV Arduino). POV means persistence of vision.