USB POV!
- May 13th, 2011
- Posted in Uncategorized
- By rucalgary
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So I continuously recived the question… “How do you change the message?” As I answered this many times before, I began to realize that my “you use an ISP programmer along with a bash script in linux” answer wasn’t going to cut it for most people. I started looking at alternatives, and finally settled on an HID implementation. I used Objective Development’s VUSB firmware (a firmware only USB implementation for AVR microcontrollers) along with a few additional components. (ceramic resonator, three resistors, two capacitors, a voltage regulator, and of course the USB mini-B connector) I also added an aditional LED because I could.
Now is where I talk about interesting things…
I use a small delay to detect whether USB is present, resulting in the small delay before the message starts. I had Room for the LED, so I added it so I could pull off our local protospace logo.
I also added a bit of code in firmware to allow additional characters to be stored in EEPROM. I figured people would like the option to add some of their own.
I created a simple C# app (visual studio 2010 ) to connect, communicate, and download new messages onto the device. It is include in the source as well.
I can’t really think of anything else right now.
Any questions can be added below…
And… The source! Available here: USB POV source (417)
Hi! It’s great how you improved your works.
Can you please extend it to use RGB LEDs
More colors would be nice.
Regards
I had thought about it, but the RGB LEDs are extremely expensive. on top of this, I would either have to multiplex lines to transistors so I could actually drive all of them, or I would have to go to a more expensive uC.
Hi!! In my pov keychain I use the leds to program it. Its not necessary to modify the hardware.
Take a look to this http://www.wayneandlayne.com/blinky_programmer/
You can use the leds as inputs by using the capacitive effect on them. You have to measure the discharge time, if the led recieves light, this time will be shorter.
So you can comunicate it with the PC by aproaching the device to your monitor
That is very clever! I knew leds could be used for input, but that never occurred to me to use it like that.
Hi rucalgary
I wanted to know about the place that you buy your copper clad boards. I am very interested in buying a batch or two.
Ah, I actually buy all my copper boards from a local store (active electronics if you are anywhere near Calgary), but you can get them online from places like digikey (digikey.com) and mouser (mouser.com), and another place that I have bought from before, electronic goldmine (http://www.goldmine-elec.com/). From there, I print them using my resist printer and etch. I actually ended up making nice boards from a Canadian company ultimatePCB.com for my kits for university, but I have not yet put the files up for those or had much time for posting cool things.