--- In Electronics_101@..., John Woolsey <jwoolsey@...> wrote:
I am working on my project. Although I want to make a USB I/O device, I
have realized I just don't have the confidence for it. So I have decided
to buy a USB I/O device and get on with things. I will come back to this
later once I am done more of the project.
So I am trying to find Criteria for the USB device. At the current time
my list is:
Must have Linux drivers (accessible from Java).
Must have Pulse Width Modulation (probably two per device).
Reversible ports would be good Input or output on each pin.
Should have at least 16 ports.
It would be nice if you could time ports to flip on for a short period
(to not burn out solenoids).
It would be used for:
Turning on and off lights. (I think 9V bulbs. Might be 12V).
Sense switches closing.
Firing Solenoids at 48V for short periods so they don't burn out
Holding Solenoids via PWM to keep them fired but not burn them out.
For 48V I am looking to get a power supply and then use a power transistor.
I have looked over the internet and I have found tons of boards that
fit. But I have no experience on which one to choose or what is the
"best board". I am in Toronto ON Can so if there is a supplier there
that would be great.
So advice me please. Any suggestions would be helpful.
thanks
John
Another way to do it is with mbed:
All of the IO functionality needs to be programmed (in C or C++) and, of course, some command language needs to be implemented for communications with the PC. Basically, only connectivity exists.
However, on the up side, you can add an ethernet RJ45 jack and the LwIP stack is already available. Now your gadget can be networked. You still have to do all the code as above but you talk to a TCP/IP socket instead of /dev/ttyUSBx
mbed is unique: all software development is done with a web browser. The entire toolchain is out on the 'cloud' somewhere and you don't have to install anything. I suppose software could be developed on a smartphone as long as it has a browser.
Watch the "Take The Tour" video. In less than 2 dozen lines of code the author creates an application with an RF ID reader and TCP/IP to send a tweet when a user arrives at home. VERY clever!
BTW, the mbed appears as a mass storage device when plugged in to USB. The USB port also supports serial IO.
Richard
