Meddling with USB

[EngineHog]

I've gotten myself involved in a project that I belive will require USB. This being said, I know very little about USB, and I'm really not interested in writing drivers. I think that my project can be done this way, but I have no idea how to go about designing things.<p>Here's the project: Basically, it's 16 digital inputs (from switches). I intend to use these inputs as a gamepad of sorts, and that's how I would like Windows to treat it. The plan is to have 2 8-button controllers fed together into the USB converter. Multiple buttons on each controller can be pressed at the same time. The final product will be a pair of Dance Dance Revolution pads like this.<p>I'm expecting to have to program a microcontroller of some sort, seeing how every "good" project these days needs one . Since the input is very simple, I would like to have just one chip for the USB and control. So any ideas on what I need to do or which ICs I should look at?<p>Thanks

[dyarker]

There are 2 or 3 places that advertize in Nuts & Volts selling USB chips and mini PCBs. They come with driver software for Windows, maybe Linux.<p>Check out www.microchip.com too, I think they're making some PICs that support USB now. Probabably have driver for download. Go to library and check last couple of months of CircuitCellar Ink mag.

[erkanyigiter]

i advise you to use FT245 from FTDI chip.
it is a parallel to USB converter. you could find sample circuits and free drivers from the FTDI's web page.<p>-Erkan

[jollyrgr]

Here is a kit you might want to consider experimenting with. It even includes software and drivers. It does not have the required number of inputs but it could get you started in the right direction:<p>http://www.ramseyelectronics.com/cgi-bi ... &key=K8055<p>As another alternative you might want to consider hacking a USB keyboard. With a keyboard you get 104 inputs (more or less) and they cost under $20. With experimentation you might be able to use ALT or CONT keys. Simply lock the ALT or CONT key down (dead short) and use the letter key of your choice. No drivers or special software needed.<p>If you get real adventurous you can use a single chip. The USB100 has potentiometer inputs and your requested 16 switch inputs. See this example:<p>http://www.intel-u-press.com/usb_dbe/Ch ... B100ds.pdf<p>[ November 26, 2004: Message edited by: Jolly Roger ]</p>

[EngineHog]

Thanks for all your help so far.<p>Jolly Roger: Wow, that USB100 chip does exactly what I want. However, it looks like it didn't go into production. I wasn't able to find anything except a press release on Fairchild's website. Their other USB chips are not what I'm looking for. <p>I looked at the Microchip and Atmel sites and they both have USB enabled microcontrollers. However, these chips would require me to be proficient in USB and I'm not sure where to begin in that regard. <p>I want this device to be "plug and play" in the same way that you can plug in a USB keyboard or mouse and have it work without any installation. I believe this is a human input device (HID) and Windows supports this in some fashion. I don't think the USB I/O boards or the USB->Parallel drivers will let me do this.

[redrocker]

On page 38 of the September 2004 edition of N&V they feature a product made by Pololu Corporation that may be what you need. It is a USB-to-serial adapter for hobbyists. From what I understand, to the PC, it looks like a serial port. (They supply drivers.) Hence, you may have to multiplex your inputs by some scheme. It only costs $23, so it is hard to go wrong.

[pboese]

The November edition of Nuts & Volts has an article using an "FT2232C Dual USB UART / FIFO" chip that sounds like it could be adapted to your needs.<p>MULTI-PROTOCOL USB
Home automation with FFTs.
by Don Powrie