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View Full Version : Basic stamp embedded into PS/2 or USB keyboard to do video text overlay



justin weber
01-13-2006, 07:00 AM
I'm new to electronics, but what I want to do is embed just the necessary components into a standard full-sized keyboard. A low cost basic stamp, the SX video module with overlay, a one or two line LCD and a on/off switch. My keyboard has a little ledge on the top. I could easily mount the lcd in there. The height of the keyboard would allow RCA connectors to be mounted in the back. This would be a little work to close it back up and align a couple ports at the same time. It would have Video in, video out and power. I would cut or unsolder the ps/2 or usb cable from the board. How I imagine it working is the lcd would clear when powered on, then you could press the arrow down to go to the next line and then press the enter key to send the text for the overlay. I could paint the keys that won't be used and somehow disable Caps lock and remove the LEDS to save power. I need some IDEA's. What would be perfect is to "remove" the numpad and store the electronics inside that and make a face place with the lcd mounted to it. My first concern is space issues(how to cram everything inside). My next is how to interface the keyboard with the stamp and have enough IO lines left over for the overlay module. And lastly I would like to somehow be able to disable all but the normal text keys(such as A-Z,a-z,0-9 and the punctuation keys. So basically I want to send a line or two of text to the screen and that's it. If anybody knows how to select colors or create some kind of area in memory mapped to a certian key that could display a logo in the bottom right corner. That way you could turn on for a few seconds and turn back off. Think of the Comedy central logo on TV. It appears for a couple seconds here and there. Then if you wanted to send some text you could just type it in and press enter. A programmable overlay controller. Maybe the non-displayable keys could be mode keys that you could position a logo or text on the screen and another to select the OSD duration. I understand that the SX video model "genlocks" automattically. I want the cost as close to $100 as possible. If I can get a decent project out of this, I plan on building one for my cousin-in-law that does news studio stuff on the internet. Let me know what you guys think.

Bean
01-13-2006, 07:34 AM
Justin,
ˇ The SX Video Overlay is serial and needs only 1 pin http://www.parallax.com/detail.asp?product_id=30015
ˇ Here is a link to a PS/2 to serial keybaord interface http://www.multilabs.net/ezKEY.html
ˇ Here is a serial LCD http://www.parallax.com/detail.asp?product_id=27979

ˇ Note that the SX Video Overlay is strictly black and white (no color).

Sounds like a great project. I don't think you have to worry about what the keys are, you can convert the key to anything you want after you read it into the basic stamp.

For making a one-off product, I don't see how you could do it for $100. The video overlay is $50, the Keyboard adapter is $20, the Serial LCD is $40. Right there is $110 not counting the keyboard (cheap) or the Basic Stamp.
If you were making 100 or so you could probably get the prices down close to $100.

Is the LCD really needed ? That would save some $$$.

Bean.

▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔
"SX-VideoˇModule" Now available from Parallax for only $28.95

http://www.parallax.com/detail.asp?product_id=30012

"SX-Video OSD module" Now available from Parallax for onlyˇ$49.95
http://www.parallax.com/detail.asp?product_id=30015

Product web site: www.sxvm.com (http://www.sxvm.com)

"Ability may get you to the top, but it takes character to keep you there."


Post Edited (Bean (Hitt Consulting)) : 1/12/2006 11:40:26 PM GMT

justin weber
01-13-2006, 08:40 AM
you know what dude, you're right. no lcd is needed. If I know it is guarenteed to work when I'm finished, then $100 is flexible. Just don't want to buy stuff and then find out I need all this other stuff. And what does a one-off product mean. Does this mean there is something similiar to what I want to do already. I just want something easy to hook up to the tv. But if it's not color then I will only be building one. By cousin-in-law won't like B/W, but I wouldn't care. That ps/2 to serial looks cool. I could just tuck the keyboard cable back into the case and plug it into the board instead of unsoldering the adapter. That way if I want to use the ps2/serial adapter for something else I can just unplug the card. thanks for the opinion.

Bean
01-13-2006, 09:11 AM
"One-off" just means your only building one of them.
I don't know of any color overlay boards. Even if you find one it will likely be a couple hundred dollars.
Bean.

▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔
"SX-VideoˇModule" Now available from Parallax for only $28.95

http://www.parallax.com/detail.asp?product_id=30012

"SX-Video OSD module" Now available from Parallax for onlyˇ$49.95
http://www.parallax.com/detail.asp?product_id=30015

Product web site: www.sxvm.com (http://www.sxvm.com)

"Ability may get you to the top, but it takes character to keep you there."
ˇ

justin weber
01-14-2006, 02:57 AM
Ok, that about solves my project. No LCD and instead of messing with the keyboard I will get a ABS plastic enclosure with the electronics inside. That way I can reuse the parts if I do find a color overlay module. I did see a color video module, but it didn't genlock to an input. In fact it was advertised for creating games. It only had an output. I think it was by the same company as the ezkey keyboard adapter.

Bean
01-14-2006, 10:36 AM
Yeah that's the ezVid, but like you say it doesn't overlay. Color output is easy compared to color genlock.
Bean.

▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔
"SX-VideoˇModule" Now available from Parallax for only $28.95

http://www.parallax.com/detail.asp?product_id=30012

"SX-Video OSD module" Now available from Parallax for onlyˇ$49.95
http://www.parallax.com/detail.asp?product_id=30015

Product web site: www.sxvm.com (http://www.sxvm.com)

"Ability may get you to the top, but it takes character to keep you there."
ˇ