View Full Version : portable pocket tv's
02-01-2007, 09:28 AM
I bought a $16.00 color portable rca tv on ebay but it does not have any input jacks, I added the 560ohm resistor to pin 15 and tried to get the baseband feature working, but the only frequency I see referenced in the code is a used channel 2 5500000, is there a list of channel frequencies somewhere? or a broadbandtv object?
02-01-2007, 09:29 AM
I also have the demo board, I think its already set up for broadband right?
02-01-2007, 10:15 AM
The Demo Board is set up for low band VHF. The comments at the end of tv.spin describe the mode settings. The comment says that channel 2 uses 55_250_000 for the frequency (54-60MHz). You might do better using 55_000_000. Channel spacing is 6MHz, so channel 3 is 60-66MHz, channel 4 is 66-72MHz, channel 5 is 72-80MHz, and channel 6 is 80-86MHz. You'll get a better signal if the frequency is a multiple of the crystal frequency, so you could try substituting a 6MHz crystal for the standard 5MHz one to do well with all the low VHF channels.
Do look at this thread near the end: http://forums.parallax.com/showthread.php?p=627973
02-01-2007, 11:23 AM
Depending on the chipset your TV uses, there is probably a place somewhere on the board where an ordinary baseband video signal is generated from the VHF or UHF received. Back in the 70's when Don Lancaster wrote his TV typewriter book, most TV's didn't have baseband video inputs, so the TV Typewriter cookbook included instructions for finding the video signal inside a TV box and tapping into it. Of course, those were analog TVs and your pocket TV is digital, but it's still highly likely that somewhere on the board the high frequency antenna input gets converted to an ordinary baseband video signal before it goes into the video processor chip. Particularly if your set contains the Sharp IR3Y29AM or IR3Y29BM, then you should be able to inject a video signal on pin 3 of that chip and see the image on the display.
02-01-2007, 05:57 PM
Considering the $16 price tage you might consider wipping the back off to have a look at the LCD, a lot of these things use off the shelf modules so the LCD part may have a PCB attached with a video connection to it.
02-01-2007, 09:48 PM
I think you all are on to something, if I can crack it open and tap into it, then I can put the display in a project box, and whalla, a 16.00 display unit!
02-01-2007, 09:51 PM
I would like to do the same thing to a broken camcorder I have with a 2.5x3" lcd display, the camcorder also has no inputs for rca, maybe I can sniff it and find the baseband line.
02-02-2007, 08:44 AM
That reminds me of something, I have the eye piece from an old camcorder, it has a tiny LCD in it and video input. I can make a propellerscope!
02-02-2007, 07:18 PM
02-02-2007, 07:21 PM
Man My tournament season is aproaching real fast, I have to get ready for the Bassmaster wekkend series, I am trying to find a prop project for bass fishing, like a digital culling system, weigh and tag your fish hit one of 5 buttons, color code the tags in the livewell, color code the led's.....
Another few Ideas: 1·is a gps data logger, that is a one button solution from the trolling motor foot pedal, hit it with your foot and it saves the spot on the sd card. 2. a solar charger for my 3 batteries the cranking battery is charged when the 200hp vmax is running, but the TM 24v system drains pretty quoick in high wind, maybe monitor voltage with the prop and use a small paddle wheel to charge the batteries from the transom.
This is fun.
Post Edited (bassmaster) : 2/2/2007 11:30:20 AM GMT
02-02-2007, 07:56 PM
Sonar glasses obviously :)