I am developing a software which needs a fingerprint ID to get access or login. Meanwhile, I can't work with Arduino and fingerprint sensors, because There is no mushc time ahead. I am thinking about using the integrated-Fingerfrint of my laptop to get Finger's ID. Is it possible to do such operation?
The short answer is yes.
The long answer is you will need a lot of things to do so. The first is you will need to find out which fingerprint scanner you have in your laptop. Then you will need to find out what SDK's that device manufacturer offers. Most will provide a image acquisition API that you can use to capture images. Most of those SDKs are going to have a C api that you will need to wrap in PInvoke calls.
Once you have images you will need an algorithm. There is a chance that the Device manufacturer sells an SDK that includes an algorithm, if not there are other companies that just build algorithms that you can purchase.
NIST also has an algorithm that is free, but it only has a C interface so again, you will have to do some work.
You might want to checkout https://www.fulcrumbiometrics.com. They support a large number of device manufactures and may be able to help you find what you are looking for.
Related
I am building a temporary controller that needs to monitor 20 separate button pushes along with another 15-20 analog and digital signals.
It also needs to output at least 20 different digital signals.
Which Netdurino will let me get all these different ports together on a single device?
It seems like the Netduino Go with multiple shield bases (image) is the way to go.
Can anyone confirm that this is the hardware solution I am looking for with the most analog and digital ports available?
Thank you,
Keith
Seeing as you're settled on the Netduino platform, I'd suggest you ask either on the Netduino forums or in their live chat room http://forums.netduino.com/index.php?/chat/
Alternately, https://electronics.stackexchange.com/ might yield better answers than stackoverflow.
Note that in the forum post you link to for the shield base, they indicate that only one shield base is supported per Netduino (at the time of writing, this may have changed):
Another noob question: How many shield bases can one connect to a NGO? Is more than 1 a viable option?
Currently just one. But with the final release I'm hoping on more :)
I've been looking for a detailed description for how USB protocol and cabling works for a long time with no luck. I am looking for a detailed yet not overcomplicated explanation of how things work on the software and hardware side of USB. Links and explanations would be appreciated. I've really run out of ideas, so it would be great if you can help me out.
This is what I do know:
USB hardware carries 4 lines- 5V power, ground, and 2 full duplex lines.
When connecting, the device can ask for a specified amount of current.
The transfer speeds for USB are quite fast compared to traditional serial connections.
When connecting, a device will output descriptors to the host describing itself. These descriptors will also be used for data.
What I don't know:
How does a program in C/C++ write directly to a USB port? Does it write to an address in the port?
How do some devices describe themselves as HID?
How do drivers work?
Everything else...
Thank you!
Identification
Every device has a (unique) Vendor and Product ID. These are provided (sold) by usb.org to identify a device. You can use a library like libusbx to enumerate all connected devices and select the one with the Vendor and Product ID you are looking for.
HID Descriptors
The point of HID descriptors is actually to do away with drivers. HID descriptors are a universal way of describing your device so you don't need to waste time on a driver for every system/architecture/etc/. (Same concept as the JVM.)
Reports
You will use either the input, output, or feature reports to read or write to your device. You send a stream to your device on the input or feature report. This is typically 8 bytes I believe. Only one of which is a single character you wish to write. The HID descriptor contains all the information you need to put together a report. Although I'm struggling to find a related link to clarify this.
Potential Libraries
In an effort to be open-minded here are all the libraries I am familiar with and some info about them.
libusb-0.1
First off is libusb-0.1. This used to be the go to and was built in to many Linux kernels and Windows I believe. It is very easy to use and there is a lot of documentation. However, the owner never updated and it wasn't edited for many years. It supports only synchronous transfers. (If an error occurs, the program can wait infinitely while it expects a transfer.)
libusbx
Next is libusbx. This is what most people would suggest today and I agree. It was published by those frustrated by the owner of libusb-0.1. The code is much more lightweight, up-to-date, and importantly does not require root privileges like libusb-0.1 and libusb-1.0 (Discussed in a second). It supports synchronous or asynchronous transfers.
libusb-1.0
Then there is libusb-1.0. This was the first update to libusb-0.1 in some number of years. It is not compatible with libusb-0.1. This was published the same day as libusbx as a retaliation (I assume) and an attempt to rectify the lack of updated content and conserve a user-base. It supports synchronous or asynchronous transfers.
hid.h
Finally, there is the hid library. This was built on top of libusb as another layer of abstraction. But honestly, I think it's just really confusing and it just adds more overhead than necessary.
Some Good Resources
Understanding HID Descriptors
Control Message Transfer Documentation (Very Good Link IMO)
Rolling Your Own HID Descriptor
Good Visual of HID Reports for Transfers
Great List of bmRequestType constants (You will need this or similar)
A simple terminal app for speaking with DigiSpark using libusbx and libusb-0.1
I know this isn't exactly what you are looking for, but maybe it will get you started!
This website has a general overview of how USB devices work:
https://www.beyondlogic.org/usbnutshell/usb1.shtml
Particular sections give answers to things from the list of things you don't know yet about USB.
E.g. to find out how USB devices identify themselves, read about USB descriptors:
https://www.beyondlogic.org/usbnutshell/usb5.shtml#DeviceDescriptors
To learn how a C/C++ program can talk to a USB device, see examples on using the libusb library:
https://github.com/libusb/libusb/tree/master/examples
To learn how USB drivers work, see a tutorial from Bootlin:
https://bootlin.com/blog/usb-slides/
I want to embed a video stream into my web page, which is part of our own cloud based software. The video should be low-latency (like video conferencing), and it would be preferable, but not required, for it to include audio. I am comfortable serving streaming binary data from the server-side, and embedding it into the page using HTML5 video.
What I am not comfortable with is the ability to capture the video data to begin with. The client does not already have a solution in place, and is looking to us for assistance. The video would be routed through our server equipment, and not be an embedded peice that connects directly to the video source.
It is a known quantity for us to use a USB or built-in camera from the computer. What I would like more information is about stand-alone cameras.
Some models of cameras have their own API documentation (example). It would seem from what I am reading that a manufacturer would typically have their own API which they repeat on many or all of their models, and that each manufacturer would be different in their API. However, I have only done surface reading and hope to gain more knowledge from someone who has already researched this, or perhaps even had first hand experience.
Do stand-alone cameras generally include an API? (Wouldn't this is a common requirement, so that security software can use multiple lines of cameras?) Or if not an API, how is the data retrieved from the on-board webserver? Is it usually flash based? Perhaps there is a re-useable video stream I could capture from there? Or is the stream formatting usually diverse?
What would I run into when trying to get the server-side to capture that data?
How does latency on a stand-alone device compare with a USB camera solution?
Do you have tips on picking out a stand-alone camera that would be a good fit for streaming through a server?
I am experienced at using JavaScript (both HTML5 and Node.JS), Perl and Java.
Each camera manufacturer has their own take on this from the point of access points; generally you should be able to ask for a snapshot or a MJPEG stream, but it can vary. Take a look at this entry on CodeProject; it tackles two common methodologies. Here's another one targeted at Foscam specifically.
Get a good NAS, I suggest Synology, check out their long list of supported IP Web Cams. You can connect them with a hub or with a router or whatever you wish. It's not a "computer" as-in "tower", but it does many computer jobs, and it can stay on while your computer is off or away, and do thing like like video feeds, torrents, backups, etc.
I'm not an expert on all the features, so I don't know how to get it to broadcast without recording, but even if it does then at least it's separate. Synology is a popular brand and there are lot of authorized and un-authorized plugins for it. Check them out and see if one suits you.
I am a ME undergrad and am designing an implant device that requires programming knowledge. I honestly have no idea how to get started and am looking for advice. Basically what I need is a way to control a stepper motor. Stepper motor's use steps (pulses) to rotate the gear head. Now this motor I'm using needs 20 steps to revolve once. I need to be able to control the # of steps I want in a day per say. The motor I'm purchasing comes with an encoder which I'm guessing connects to the circuit board. Now what I want to do is have an external control (like a remote control for a toy)that can set these rates. I don't know anything about radio transmitters, or how to program the circuit board to do this for me. Any help would be appreciated, or books I can look into, websites, or tutorials. Thanks.
There are many ways of solving this problem, but it is more of a systems engineering question than a programming question; until you know what the system looks like, there is no way of determining what parts will be implemented in software. More details would be required to provide a specific answer.
For example what are the security/safety considerations?
What wireless technology do you need to use? e.g. RF or IR, if RF then licensing may be an issue, and that may vary from country to country. You could use BlueTooth, ZigBee, or even WiFi, but these technologies are probably more expensive and complex than necessary for such a simple application. If IR then is immunity from interference from TV remotes or PC IrDA ports or similar required?
If the commands/signals from the remote are complex you will probably need both the remote and the motor driver to incorporate a micro-controller and software. On the other hand if you just need increase/decrease functions then it would be entirely possible to implement the remote functionality you describe without any processing at all (depending on teh communication technology you choose).
What is the motor encoder for? Stepper motors do not normally need an encoder since the controller can simply count steps executed in either direction to determine position. Is the encoder incremental or absolute? If it is incremental, then it is certainly not needed; if it is absolute than it may be useful if you need to know the exact position of the motor on power-up without having to perform an initialisation or requiring end-stop switches.
You mentioned a "circuit board"; what hardware do you already have? What does it do? Do you have documentation for it? If it is commercially available, can you provide a link so we can see the documentation?
As you can see you have more system-level design issues to solve before you even consider software implementation, so the question is not yet ready to be answered here on SO. I suggest you seek out your university's EE department and team-up with someone with electronics expertise do design a complete system, then consider the software aspects.
Well worth taking a look at the Microchip site:
http://www.microchip.com/forums/f170.aspx
They produce microcontrollers that can be programmed to do exactly what you require (and a lot more).
As a hobby project to keep myself out of trouble, I'd like to build a little programmer timer device. It will basically accept a program which is a list of times and then count down from each time.
I'd like to use a C or Java micro controller. I have used BASIC in the past to make a little autonomous robot, so this time around I'd like something different.
What micro controller and display would you recommend? I am looking to keep it simple, so the program would be loaded into memory via computer (serial is ok, but USB would make it easier)
Just use a PIC like 16F84 or 16F877 for this. It is more than enough.
As LCD use a 16 x 2 LCD. It is easy to use + will give a nice look to your project.
LCD
The language is not a matter. You can use PIC C, Micro C or any thing you like. The LCD's interface is really easy to drive.
As other components you will just need the crystal and 2 capacitors as oscillator + pull up resister. The rest of the components depend on the input method that you are going to use to set the times.
If you are using a computer to load the list then you will need additional circuit to change the protocols. Use MAX 232 to do that. If you want to use USB, you need to go ahead and use a PIC with USB support. (18F series)
(source: sodoityourself.com)
This is a set of nice tutorials you can use. You can purchase the products from them as well. I purchased once from them.
I would go with the msp430. An ez430 is $20 and you can get them at digikey or from ti directly, then sets of 3 microcontroller boards for $10 after that. llvm and gcc (and binutils) compiler support. Super simple to program, extremely small and extremely low power.
There are many ways to do this, and a number of people have already given pretty good suggestions AVR or PIC are good starting points for a microcontroller to work with that doesn't require too much in the way of complicated setup (hardware & software) or expense (these micros are very cheap). Honestly I'm somewhat surprised that nobody has mentioned Arduino here yet, which happens to have the advantage of being pretty easy to get started with, provides a USB connection (USB->Serial, really), and if you don't like the board that the ATMega MCU is plugged into, you can later plug it in wherever you might want it. Also, while the provided programming environment provides some high level tools to easily protype things you're still free to tweak the registers on the device and write any C code you might want to run on it.
As for an LCD display to use, I would recommend looking for anything that's either based on an HD44780 or emulates the behavior of one. These will typically use a set of parallel lines for talking to the display, but there are tons code examples for interfacing with these. In Arduino's case, you can find examples for this type of display, and many others, on the Arduino Playground here: http://www.arduino.cc/playground/Code/LCD
As far as a clock is concerned, you can use the built-in clock that many 8-bit micros these days provide, although they're not always ideal in terms of precision. You can find an example for Arduino on doing this sort of thing here: http://www.arduino.cc/playground/Code/DateTime. If you want something that might be a little more precise you can get a DS1307 (Arduino example: http://www.arduino.cc/cgi-bin/yabb2/YaBB.pl?num=1191209057/0).
I don't necessarily mean to ram you towards an Arduino, since there are a huge number of ways to do this sort of thing. Lately I've been working with 32-bit ARM micros (don't do that route first, much steeper learning curve, but they have many benefits) and I might use something in that ecosystem these days, but the Arduino is easy to recommend because it's relatively inexpensive, there's a large community of people out there using it, and chances are you can find a code example for at least part of what you're trying to do. When you need something that has more horsepower, configuration options, or RAM, there are options out there.
Here are a few places where you can find some neat hardware (Arduino-related and otherwise) for projects like the one you're describing:
SparkFun Electronics
Adafruit Industries
DigiKey (this is a general electronics supplier, they have a bit of everything)
There are certainly tons more, though :-)
I agree with the other answers about using a PIC.
The PIC16F family does have C compilers available, though it is not ideally suited for C code. If performance is an issue, the 18F family would be better.
Note also that some PICs have internal RC oscillators. These aren't as precise as external crystals, but if that doesn't matter, then it's one less component (or three with its capacitors) to put on your board.
Microchip's ICD PIC programmer (for downloading and debugging your PIC software) plugs into the PC's USB port, and connects to the microcontroller via an RJ-11 connector.
Separately, if you want the software on the microcontroller to send data to the PC (e.g. to print messages in HyperTerminal), you can use a USB to RS232/TTL converter. One end goes into your PC's USB socket, and appears as a normal serial port; the other comes out to 5 V or 3.3 V signals that can be connected directly to your processor's UART, with no level-shifting required.
We've used TTL-232R-3V3 from FDTI Chip, which works perfectly for this kind of application.
There are several ways to do this, and there is a lot of information on the net. If you are going to use micro controllers then you might need to invest in some programming equipment for them. This won't cost you much though.
Simplest way is to use the sinus wave from the power grid. In Europe the AC power has a frequency of 50Hz, and you can use that as the basis for your clock signal.
I've used Atmel's ATtiny and ATmega, which are great for programming simple and advanced projects. You can program it with C or Assembly, there are lots of great projects for it on the net, and the programmers available are very cheap.
Here is a project I found by Googling AVR 7 segment clock.
A second vote for PIC. Also, I recommend the magazine Circuit Cellar Ink. Some technical bookstores carry it, or you can subscribe: http://www.circellar.com/
PIC series will be good, since you are creating a timer, I recommend C or Assembly (Assembly is good), and use MPLAB as the development environment. You can check how accurate your timer with 'Stopwatch' in MPLAB. Also PIC16F877 has built in Hardware Serial Port. Also PIC16F628 has a built in Hardware serial port. But PIC16F877 has more ports. For more accurate timers, using higher frequency oscillators is recommended.