snyderw@pawl18.pawl.rpi.edu (Wilson P. Snyder II) (03/15/88)
Hello, I would like to know if it is possible to make a very low power television transmitter. Here's the catch, it needs to fit into a HO Scale model railroad boxcar (About 2" by 5" by 5"). The data does not need to be transmitted onto the standard broadcast band, nor does the format need to be standard. Of course, if it is not a receiver is needed. I plan to use a small Semiconductor Imags sensor for the input, so the input could be digital (???). Finally, color is needed. Any help would be welcome. (The radio signal only needs to make it ten feet or so.) ______________________________________________________________________ Wilson P. Snyder II beowulf!lunge!snyderw@steinmez.UUCP 318 Crockett Hall, RPI (uunet!steinmez!bewulf!lunge!snyderw) Troy, NY 12180-3590 (518) 276-7189, or (802) 658-3799 if summer ----------------------------------------------------------------------
garnett@batcomputer.tn.cornell.edu (Roger Garnett) (03/16/88)
In article <533@imagine.PAWL.RPI.EDU> snyderw@pawl18.pawl.rpi.edu (Wilson P. Snyder II) writes: > > Hello, I would like to know if it is possible to make a very >low power television transmitter. Here's the catch, it needs to fit >into a HO Scale model railroad boxcar (About 2" by 5" by 5"). >is needed. I plan to use a small Semiconductor Imags sensor for the input, >so the input could be digital (???). Finally, color is needed. > Any help would be welcome. (The radio signal only needs to make it >ten feet or so.) > Yes! you can. There are some cheap and dirty ways to do it too. Of course things like this are 'officially' controlled by the FCC... If you have a composite vidio signal (output from camera, computer, vcr, etc), you can feed it in to a rf converter. Small, cheap rf converters can be made with few parts (I don't have details here) but an eaiser way is to use a converter from a vidio game, home computer, vcr, etc. Any old, dead VIC 20, sinclair, Atari, or VCR may be a good candidate. There were even some converters sold seperatly. You can take the output of the converter and feed it to an antenna of some sort (wire) and pick up the result on a nearby TV. Some rf converters are pretty amazing, Back about 15 years ago I fed the rf output from a Sony Porta-Pac VTR into our TV antenna and then aimed the camera at our neighbors house. I then went next door to "watch" TV. And what do you Know, guess what was showing on channel 3? My neighbor couldn't figure out why his house was a star... IF you do this it helps to have channel 3 or 4 unused by a local station, they would probubly kill your weak signal. And remember you don't know who might be watching. Also, you can feed audio into some converters as well as vidio. So, a camera mounted in a model train, huh? Nice ride. I have been noticing the increase of such subjects-eye-view cameras, in racing cars, those mad lughe (sic?) sledders in the olympics, etc. So, remember, some where, some time, some one may be watching, so smile! you're on candid camera... -------- Roger Garnett (garnett@batcomputer) / /||^^\ \ Cornell Phonetics Lab (garnett@tcgould.TN.CORNELL.EDU) | |\/ || _ | Ithaca N.Y. (bitnet: sggy@cornellC) | | || | | \ ||__/ / ------- SAFETY FAST! okbye
paulf@umunhum.STANFORD.EDU (Paul Flaherty) (03/17/88)
A far better solution would be to wait for Lionel's TrainCam, due out some time this summer, at a cost of about $500. -=Paul Flaherty, N9FZX | Computer Systems Laboratory | "panic: getfs: bad magic" Stanford University | ->paulf@shasta.Stanford.EDU | --4.3bsd Unix
david@daisy.UUCP (David Schachter) (03/18/88)
I read of an exceedingly cheap low power NTSC-to-RF converter. The power output may be too low; I'm sure someone will post a small amp design. The method, written in Electronics magazine a decade or so ago, is to put NTSC signal into a TTL inverter chip. One type of inverter (LS, I think) can't respond fast enough to the input signal, goes into it's linear range of operation, distorts horribly (since TTL gates aren't designed to be good linear amplifiers!), and generates the correct signal for various TV channels. Of course, it also generates lot of other crap too. And you can't get audio. And I doubt color will work too well. And the resolution may not be too great. But the cost is low. If you blow up something, don't blame me. I never built it; I simply read the article and was impressed by the simplicity and cleverness. -- David Schachter Standard disclaimer: the site I'm posting from doesn't adhere to my opinions. "I'm not home right now. Please wait for the tone, then hang up. Thank you."