I'm a newbie using LabView for my project. So I'm developing a program that gathers data from sensors that attach in the DAQmx board and also a spectrometer from STS-VIS ocean optic. At the first developing, I combine both devices in one loop inside the same flat structure, but I got an error saying: "The application is not able to keep up with the hardware acquisition." I cannot get the data showing on the graph for both devices, but it was just fine if I run it separately. And I found the solution saying that I need to separate both devices in a different while loop process because it may have different buffer size (?). I did it and it worked that all the sensors are showing in each graph. But the weird thing is, I need to stop the program first at the first run, then run it again for the second time for getting the graph showing in the application. Can anyone tell me what I did wrong and give me a solution? Due to the project rule I cannot share my Vi here publicly, but if anyone interested to help, I'd like to share it personally. Thank you.
you are doing right thing but you have to understand how Data acquisition work in LabVIEW and hardware.
you can increase hardware buffer Programmatically using property node or try to read fast as possible then you dont need two separate loop.
NI
I work currently with a NI DAQmx device too and became desprate using LabView because there is not good documentation and/or examples. Then I started to use Python which I found more intuitively. The only disadvantage is that the userinterface is not so easily generated, but for this one can use the QT Designer (open source programm avaiable online).
I'm using a USB-6356 DAQ board to control an IC via SPI.
I'm using parts of the NI SPI Digital Waveform library to create the digital waveform, then a small wrapper VI to transmit the code.
My IC measures temperature on an RTD, and currently the controlling VI has a 'push for single measurement' style button.
When I push it, the temperature is returned by a series of other VIs running the SPI communication.
After some number of pushes (clicking the button very quickly makes this happen more quickly in time, but not necessarily in number of clicks), the VI generates an error -200361, which is nominally FIFO buffer overflow on the DAQ board.
It's unclear to me if that could actually be the cause of the problem, but I don't think so...
An NI guide describing this error for USB-600{0,8,9} devices looks promising, but following the suggestions didn't help me. I substituted 'DI.UsbXferReqCount' for the analog equivalent, since my read task is digital. Reading the default returned 4, so I changed the property to write and selected '1', but this made no difference.
I tried uninstalling the DAQ board using the Device Manager, unplugging and replugging, but this also didn't change anything.
My guess is that additional clock samples are generated after the end of the 'Finite Samples' part for the Read and Write tasks, and that these might be adding blank data that overflows, but the temperatures returned don't indicate strange data, and I'd have assumed that if this were the case, my VIs would be unable to interpret the data read in as the correct temperature.
I've attached an image of the block diagram for the Transmit VI I'm using, but actually getting it to run would require an entire library of VIs.
The controlling VI is attached to a nearly identical forum post at NI forums.
I think USB-6356 don't have output buffers used for Digital signal. You can try it by NI-MAX, if you select the digital output, you may find that there is no parameters for Samples. It's only output a bool-value(0 or 1) in one time.
You can also use DAQ Assistant in LabVIEW, when you config Digital output, if you select N-Samples or Continuous samples, then push OK button, here comes a Dialog that tell you there is no buffer for lines that you selected.
As explained here:
http://www.edn.com/design/sensors/4407580/Brushless-DC-Motors-Part-II--Control-Principles
, switching the motor windings should occur when the back-emf voltage across the 1/2 VDCC value. How to effectively perform that in stm32f4 which don't has embedded comparator module?
It seems the only way is using analog watchdog with selecting next single waited channel at every moment when interrupt happens?
And how to be if I want drive 4 bldc from single stm32 chip?
There are few ways you can achieve this. The most popular way with STM32's are sensing the floating phase. The technique is little different to what your link is suggesting, nevertheless there are plenty of example codes to get this going.
Here is a nice explanation of ST's patented 3 resistor BLDLC position sensing method (and some other techniques).
A nice starting point would be this manual.
STM32 supports for two motor control timers (TIM1 and TIM8). You can use them to drive 2 BLDC motors. Nonetheless, it would not limit you to use other timers in combination in order to drive more BLDCs but would demand some additional programming complexity.
I am planning on doing a small arduino project and would like to know if what I'm thinking would work with a regular arduino board. I'm thinking of buying an Arduino Uno for my project, along with an IR LED and an IR sensor. So here's what I want to go with this:
I want to point the LED towards the sensor, so that the sensor is always detecting light. Then', I'll start "cutting" that light (say, with with my hand) several times. I want the arduino program to time the intervals between the times the light is "cut" and send these times to my computer via USB, so I can process this data.
I've seen many people talk about serial communication between an arduino board and a computer, but I'm not sure how that works. Will it use the same usb connector I use to upload programs to the board, or do I have to buy anything else?
EDIT: tl;dr: I guess my question, in the end, is twofold:
1) Am I able to "talk" to my computer using the built-in USB connector on the board, or is that used solely for uploading programs and I need to buy another one? and
2) Is this project feasible with an Arduino Uno board?
Thanks for the help!
Yes, your project is very feasible.
You use the built in USB connector to both program the device and communicate with it. Check out some examples on the Serial Reference Page
For reading the sensor, you'll want to use either a digital or analog input. For a digital input, you'll likely have to external components to control the light threshold, but it will provide a simple yes or no if something is in front of it. With an analog input, you can use a threshold in code to determine when your hand passes.
Timing can either be done on device with the Millis() function or on the connected computer.
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.