Please elaborate, for those of us who missed out on and never heard of this now 20-year old bit. What happened? Why was it so funny?
It’s my impression that, in the comics, he has in fact donated the signal they use. And he does in the first Burton movie as well.
A bit of a hijack, but how is it possible that the police department and city government could openly advertise that they cannot enforce the rule of law and need the help of a vigilante? At a minimum, Batman would have to have permanent deputy status, and there is simply no way that could be extended to someone of unknown identity, unanswerable to civic oversight. I could just see it if it were a matter of superhuman villians who can only be taken down by other superhumans, but Gotham’s freak show mostly doesn’t qualify.
Of course, this is like asking why the Joker hasn’t received a bullet to the back of the head long ago, but still…
It was used on buildings and clouds. There were many newspaper articles about it throughout the 30s, though this is one of the few magazine articles that is linkable to. You can also find mentions of it in sites about Harry “Death Ray” Grindell-Matthews.
Some articles give the projectors the ability to project images that would be visible even without clouds.
What, you thought the guy writing Batman comics could make cool stuff up? 
Lumpy, the 1940s Batman started out as a vigilante wanted by the police but soon turned into a beloved honorary member of the police force, acclaimed by everyone and a public daytime figure celebrated by all decent people. Just like Superman was an honorary avenger for all the nations of earth. Forties comic portrayals of superheroes are nothing like they are today.
This is way off-topic, but reading this I recalled how when the first burton movie came out, I thought the symbol was of an open mouth i.e. the subtration image of the bat shape. :smack:
In fairness I was a child at the time, and in the logo it’s the outside that’s solid.
That also never happens in Gotham.
Ohhh. Um, this is embarrassing to admit, but I always saw that as a mouth too, and assumed it was meant to be a bat’s mouth. :o In fairness, I didn’t look at it all that closely.
That was pretty cool. I wonder if it actually worked. I say that because if it did, why isn’t something like that used any more? I’ve seen billion jiggle watt search lights for night time events but never anything like that. I feel cheated.
I also note that the article doesn’t show any actual photographs of it in action. Were I the cynical sort, I’d suspect that they had an idea that they had almost working, and just needed a little more funding to finish it, and then after that they’d just need a little more, and so on. Oh, wait, I do think that… I guess I am the cynical sort.
You’ll notice that they didn’t just slap a transparency on the searchlight, though. It looks as if they built themselves a projector, which is a whole 'nother thing.
Thank you. You made my day. 
I vaguely recall it was along the lines of “Okay, the crisis is over and everything’s okay, so they end the movie testing the Bat-signal. Does Batman come running in, saying in ‘Yeah, whaddya want?’ and they’d be ‘We’re just testing it, sorry.’”
The DC Comics Roleplaying Game, derived from canon materials, mentions that a beeper-type device has been intergrated into the Batsignal.
Re: DC Comics, & Beepers.
In the Gotham Central comic book series they forced a secretary named Stacy to switch it because legally the officers couldn’t.
It’s implied that when Gordon did it, he just never gave a shit about the rules.
Nowadays Batman should have a cellphone that can only be traced to a shell company and no further, say a Jersey Company. Then Batman is smart enough to reprogram the GPS tracking on it so that it is encrypted and can only be accessed by Alfred, not by some idiot with a search warrant. Hell, it will probably alert him with a harmless text message when someone accesses it, so as not to give away to third parties that he knows he’s being tracked.
The 1960s Batman TV series answered that in Episode 6 “Batman Is Riled” when Batman told the Joker “as a duly deputized agent of the law,” he was arresting the Clown Prince of Crime.
These are not the droids you’re looking for. He can go about his business.
The sky projector certainly worked, and was demonstrated several times (there’s a photo of it in operation in the other link in Exapno’s post – it just doesn’t seem to have attracted sufficient backing as a commercial proposition, for some reason.
Other than that, though, you’ve pretty much summarised Grindell-Matthews’ entire career.