"That's ... probably a good idea," Robin agrees.

"Okay — so: a mental shielding talisman, generic reinforcement, hope and will batteries, maybe some emotion-based nonlethal weaponry if we can show that it's safe ... Oh! You mentioned maybe being able to do a gas-mask or similar as well, and it's always good to have backups there in case of failures. The shielding talisman looked pretty small; how big do you think an emotion-powered gas-mask would be? Or the batteries, for that matter?"

"It's hard to say? A lot of it depends on how long you want it to last, how durable you want it to be, and how much ambient hope you're expecting it to be exposed to. Or really, what the 'charger' situation is, because in principle it should be fairly easy to make a good amount of minimal devices that can gain charge from hope exposure out in the world and then use those to expand battery life of your stuff dynamically? I think... pretty small? The green lanterns can do what they do with a ring that's only an inch or two across, so the fundamental limits are pretty loose. Realistically... I could make something as small as the shielding talisman work or maybe a bit smaller, but making it bigger would help the battery life a good bit and make it a little easier to make it and get the most out of it." 

"So we're going to need to do some testing to determine exact battery life," they muse. "Our current masks target a 6-hour run time, although we almost never need them for longer than an hour. Getting a similar lifetime from your device would be nice, but not essential."

They turn to lean against the table, arms crossed.

"How much ambient hope we run into is ... harder to quantify. On the one hand, I think people who are scared often hope pretty fiercely? On the other hand, Gotham doesn't have the most ... hopeful air. Maybe what we should be thinking about is what test devices you could easily make to get a better understanding of the design parameters here. Could you make a really simple gadget that shows how much charge it has, and how much it is recharging? And ideally logs that information for later, but we can ducktape it to a sensor or something. That way I could wear it around for a few days or weeks, and we can get a better idea of how much of a problem charge is going to be."

"An indicator of how much it's charging is pretty simple - I think it might actually glow in response to that by default? A charge indicator would probably be a little more finnicky - giving someone who touches it at least a general idea of the charge state should be... relatively easy, though? Making some sort of more verbose system isn't out of the question, but my first thought was definitely to try to make it as simple as possible? Really, I'll probably just have to try out all the options at some point and see what trying to make it work like that looks like." 

"It does make sense to keep things simple. I guess I could get a photodiode and a microcontroller and let the microcontroller take the integral of the recharge rate ..."

They walk over to a set of shelves against the back wall, and rummage around for parts.

"I'll need to do the programming later," they remark, "but I think this case should do. Could you make a test unit that glows more or less in response to how much its charging that would fit in that little space there?"

"Yep! For what it's worth, the crystal isn't even strictly necessary - if you want, I can just scribble something down on a bit of paper that should technically do it, if that's all you are looking for?" 

The ideal design is pretty simple - honestly, it's barely really a 'design' at all. Just the blue sigil, and a bit of structure beneath the surface around the inner circle to encourage a small intuition-guided fraction of the input Capital B blue light out as lowercase b blue light, and a bit of flexibility to make sure someone can get out the power later. It's not worth handcrafting, and the shaping of the emotions is about as simple as it could be, really, so it'll be a breeze to make either way. 

"Does the material affect its absorbtion? If so, I'd like something made of the same material as the expected final product. If not, then a paper design would be great."

There's a swish of displaced air, and a single sheet of paper flutters to the table.

Crystallographic scans normal — no detectable difference from naturally occurring gemstones, other than face/crystal alignment. Dropping test items off with Zatara for magical analysis.

"It will, yeah." 

Okay, so... Just a wafer of the sapphire, then? Shouldn't take too too long either for the generation or the imbuement - just a bit of idle hope that she can bring hope, and that she can make something cool and exciting and keep on doing more and more of that! In a handful of minutes, it's done. 

"Here."

"Nice!"

Robin slots it into their ersatz device, and then running some calibration checks on the sensor.

"Okay — I'll wear this around, and we can meet to go over the results in a few days?" they suggest. "That data is probably pretty important for figuring out the designs of any civilian equipment as well, but perhaps we can brainstorm what might be useful or saleable in the meanwhile?"

She nods firmly. 

"Yeah! So... there's a few things that I want to work on, but that are a little out of scope for now? I know that lanterns can do space flight and even FTL, but that's probably a bit out of scope without a dedicated power making that easier. Something for flight could also be a good idea, though it might be a little hard to demonstrate that it's safe? Same goes for an environmental protection set up. I could probably make some sort of empathic holography device, but I'm not sure how much people would really be willing to pay a big premium for that? I know there's plenty of tricks that can approximate that sort of thing well enough if you're willing to deal with some fussy technology. There's divinatory tools as well, but making those in a way that doesn't make them really privacy invadey seems hard enough to make it a bad idea to start on." 

"Hmm ..."

Robin taps their finger to their chin contemplatively.

"So technological holography is actually pretty fussy. The focusing crystals are rare and expensive. If you could produce something that was cheaper or more robust there might be a market for it. But when you say 'empathic holography', are you thinking glowing blue wireframes, or could you produce something like a disguise talisman?"

She hums. 

"I could make something that makes a glowing blue and/or green wireframe, or even make it a physical object you could touch and manipulate? More speculatively, I could make some sort of device that records an impression of what someone focused on in their mind's eye that anyone could touch and get a sense of, but making a proper illusory disguise would either need magic or adding more colors to the mix - I guess in principle I could just add red to make an image out of rgb? It would be purely a visual thing, though, without adding even more complication, and the red light of rage isn't necessarily the most natural tool for the job. Physical robustness should be easy, but I'm less sure about making the disguise itself 'robust' persay." 

"Even if it's limited to playing with shades of blue and green, that's still somewhat useful. I'm not sure there will be broad uses for something like that, but you probably don't want to be producing millions of units anyway."

"Oh! What about emergency distress beacons? They make pretty good ones for hikers and so on, but they mostly require radio communications, which supervillains have been known to jam in the past. Could you make a remote distress beacon — or maybe even something more like a general phone — that doesn't rely on radio?"

"So... one of the simplest possible things you can do with the lights is just make a bunch of light? Making a distress beacon that just creates a giant blue or green spotlight in the sky would be really straightforward. Doing something better than morse code for communications would be tricky, though - I think the green lanterns have something like that, but I have only the vaguest idea of how you would go about making that work with my stuff." 

"Fair. 'Instantaneous giant blue or green spotlight' does have some applications, though. Actually, how bright can you make the produced light? Could you do flashbangs, maybe with debilitating emotional effects?"

Robin's face lights up a little bit at the idea of flashbangs, even though they've been generally staying away from the topic of weaponry.

"I could do a flashbang? The biggest problem with those would likely just be precisely capping it so that it's effective but not crippling. Emotional effects are possible but probably not very efficient - will and hope aren't the most natural tools for disabling people, and it'd probably be pretty fussy to make it linger the way you'd want it to. Another emotion could work, but again we have the problem of potentially creating some sort of spiritual or neurological injury, so..." 

"Ah, yeah, that makes sense. A dial-a-yield flashbang is still a useful thing to have, but maybe conventional would be better for that."

Robin frowns at the equipment for a while.

"My initial surge of ideas is kind of running out. Do you want to switch problems and/or spar to let our brains have a break? Batman sort of implied that you had additional plans."

"I mean... there's so many that it's hard to list them all! I have a few hairbrained schemes for things that might theoretically work if the details of the physics of a few things happen to work out in a nice way - if converting to hellenism is easy enough and the ward's power is unconstrained enough, it would probably be a good idea to create a giant underground and/or underwater metropolis of immortals? And you if Captain Cold's technology is anything like as thermodynamically ignorant as it looks like there's probably a lot of room for reglaciating the artic or working on global warming, say. Even if not, I could probably try something with Weather Wizard's technology and do a lot with that? My big problem is that I don't have a great sense of what's both tractable technically and politically, I guess? Honestly, I think that's probably the sort of thing that'd be best as a problem to sleep on and poke at later." 

She blinks. 

"Oh yes! I did want to try to get a bit more used to fighting! Do you want me to just use what I have right now or have me try to test out particular combat powersets? I'm fine with either, but Batman mentioned that he was interested in using me to test out some strategies for fighting particular foes, so leaning a little towards to see how well that works out?" 

She glances over at batman questioningly.

"I'm curious to see how you do with your current powerset," Batman replies. "Since it wasn't optimized for combat — but, if you plan to spend most of your time building things, you'll often have to respond to an emergency without a powerset optimized for combat."

"This is going to be great! Step up on the mat, here. The cave has holographic force padding, so neither of us will go flying off it. What's your prior experience with hand-to-hand combat, since I assume you haven't had much chance to practiced ranged combat with powers?"

She steps up to the mat, rings glimmering with excited focus on her fingers. 

"Not a lot! As a kid, I did a bit of karate, so I still know a little how to fall and maybe how to punch? But really, you should probably treat me as more or less totally green." 

Robin nods, and then starts doing a set of simple stretches.

"Falling safely is a good skill to have! I'm a red belt in karate, although it's not my main focus. So I should be good enough to keep either of us from getting injured. Go ahead and come at me when you're ready, although if you want to fall a few times to get a feel for the mat, be my guest."

"With my powers or?" 

"With powers! It'll be more fun that way, and we'll both get more out of it. Unless you overwhelm me immediately and I have to tap out, in which case that's good to know too."