LCD Hud for Airsoft

Projects General Guidance
1

Hi there so I've been learning a bit about ardunos and stuff for work (to the point that I want one for myself, ordering my own mega from Sparkfun this week)
And I've been plotting something.

So I was wondering if they make an LCD display, with no back to it. I don't really mind the pinout for it too much but I want to make it into an info screen for inside of my mask when playing airsoft. Readout random things like time, temperature, Maybe throw in one of those GPS shields so i know where I am.

That whole thing I know I can do, and it won't be too much trouble to even use one of the little 2x16 displays. But what I really want to try to do for the luls is make an LCD display that sits in the center of my helmet (or maybe a couple), using some of those 128x64 screens I know they have. But take the backs off of them (if thats possible). Then using a gyro on the gun, and one mounted in my helmet, constantly test where the gun is pointed. And while its pointed in the direction that a screen is covering, generate a crosshair or a circle over where the gun is aiming for when I fire.

I know theres no real point to this, but it seems like a fun experiment to try. I already know there will be lots of error in aiming with this due to the distance between the helmet and the gun and stuff like that. But I know that if I had an even slightly working rendition of something like this, I'd be able to talk my friends into helping me with future arduno projects (or maybe even start their own)

So if this seems even slightly feasible to anyone, please gimme a shout, I'd like someone elses input on this please.

2

How are you going to be able to focus on something that close to your eye?

3

The helemt I plan on wearing for this, the glass sits about 3-4in away from my face. On top of that the goal isn't really to do something for accuracy, just a little something that gives you a reticle (could be a large one so you dont even need to focus) to point generally where the shots may land. It would take a bit of fine tuning, probably would end up operating over just 1 eye in the first test so I dont have to deal with trying to get things lined up to be visible for both eyes.

4

You might be better off starting with something like this:

and modifying it. I have seen cheap Chinese made versions of those sell for less than $50 USD.

5

wizdum:
You might be better off starting with something like this:

http://www.amazon.com/Myvu-Personal-Viewer-Universal-MA-0483/dp/B000VKY0J6/ref=sr_1_41?ie=UTF8&qid=1326742069&sr=8-41

and modifying it. I have seen cheap Chinese made versions of those sell for less than $50 USD.

I don't know if modding one of those would be feasible or not. The issue on those is whether they use a backlit LCD, or an OLED for the display. If the latter, you can't mod it for "see-thru" (whereas at least in theory you can remove the backlight and polarizing pieced on an LCD and use it in a "see-thru" way; though I doubt this could be done with standard text or graphic LCDs as there is the PCB to consider).

For the OP:

I would advise you to look into a small graphical VFD instead of an LCD, mainly for the contrast; VFDs are much brighter than LCDs, and you will be able to easily see everything even in daylight. Then, I would build your HUD so that you mount the VFD in such a manner that you can bounce the image with mirrors in a periscope fashion to your eye, with the final mirror being, of course, half-silvered, so it is see-thru (this is also a reason to use a VFD, because of optical transmission losses). You might need a lens or two along the path from the VFD to the first mirror to magnify it as well.

You might also be able to get away with using a small OLED display; there are a few out there that are small, and use an SPI interface (and have an on-board memory buffer); the only issue again is daylight viewing and transmission losses - but they might be easier to source than a small VFD.

6

Nikarus:
Hi there so I've been learning a bit about ardunos and stuff for work (to the point that I want one for myself, ordering my own mega from Sparkfun this week)
And I've been plotting something.

So I was wondering if they make an LCD display, with no back to it. I don't really mind the pinout for it too much but I want to make it into an info screen for inside of my mask when playing airsoft. Readout random things like time, temperature, Maybe throw in one of those GPS shields so i know where I am.

That whole thing I know I can do, and it won't be too much trouble to even use one of the little 2x16 displays. But what I really want to try to do for the luls is make an LCD display that sits in the center of my helmet (or maybe a couple), using some of those 128x64 screens I know they have. But take the backs off of them (if thats possible). Then using a gyro on the gun, and one mounted in my helmet, constantly test where the gun is pointed. And while its pointed in the direction that a screen is covering, generate a crosshair or a circle over where the gun is aiming for when I fire.

I know theres no real point to this, but it seems like a fun experiment to try. I already know there will be lots of error in aiming with this due to the distance between the helmet and the gun and stuff like that. But I know that if I had an even slightly working rendition of something like this, I'd be able to talk my friends into helping me with future arduno projects (or maybe even start their own)

So if this seems even slightly feasible to anyone, please gimme a shout, I'd like someone elses input on this please.

You'd be better off with a semi-transparent piece of plastic, and beaming an image on to it. you should google "HUD" (Heads up display). To give you an example, there are HUD units for cars that use a piece of film you stick to the corner of your windshield, and the device beams an image of your speed onto it, which allows you to see the image as if it were hovering in space.

I have never seen a consumer lcd display that is transparent (in small sizes). plus, what if you fall..you want LCD glass in your eyes?

7

I would say that you have zero chance of determining which way the gun is pointing and it's position relative to your head well enough to tell whether the impact point was within your field of view, let alone to give any meaningful crosshairs.

What might be more feasible is to put a camera on your gunsights, perhaps to record it but also to give a live feed to your goggles. (Being able to shoot from behind cover could be quite handy?)

So far, I don't see Arduino being any help with either of these projects, though.

8

wizdum
thanks for reply, though what you describe is a little out of the scope of what I know or can probably work with for now. TY anyways.

cr0sh
nice call on the OLED display (that would be the ultimate of what I'd want to do, but those probably cost a lot more then I'd be willing to pay) I'm gonna look into the VFDs, they seem like the best shot for what I could go with and yeah I've got space to bounce light a bit in my helmet (its pretty big in there, got a couple CPU fans to keep me cool too) And yeah it'd probably be pretty impossible to use an LCD display for this. But hey isn't that the point of asking, now theres 2 conceptually feasible ways to make the "screen" appear, TY for that.

evanrich
yep gonna be looking into the VFDs that cr0sh brought up which is basically what you suggested. As for the glass in the eyes, There'd definately be a layer of plastic that I place between me and the screen in-case of stuff like that.

PeterH
I've done the camera before, adn yeah it works but the screen can be quite annoying. I still ahve the screen (with me) and the camera on my gun most of the time in games now for proof of what I've done when 16yr olds try to argue with the ref that they haven't been hit. But for shooting from cover and things, just use mirrors mostly, or I have one of my friends flank, though usually I'm in a manner in which I have a good view from cover and can fire regularly without getting seen or fired back at (best method).

Since this project is mostly a "hey guys check out what I built" project, it's not that big of a deal. But I don't understand why it would be difficult to tell where the gun is pointed relative to the head.

3 axes of gyro on the head, 3 axes of gyro on the gun, and 3 axes on the chest (chest is there solely for a setpoint and extra layer of math for exactness) Compare 1 direction of the head and gun to eachother, you know how far apart they are in that angle, compare them in another you got another. After getting the screen in the helmet, measure the angle of view that it accounts for, then make it so that when the difference between the helmet and the gun is within that range, it generates the crosshair. Yeah there will be error, and it won't be accurate at close range, but IDC about that for now. There'd definitely be a way in the program to calibrate it, turn on, aim down the sights normally to set "Home" for the gyros, then hit a button to save that and use it for the match. Even if it moves a little bit through to the course of a game I could reset it. Or maybe a couple dials to manually adjust it.
Umm if you could explain why the data from the gyros would be useless I'd like to know.

And well, thanks for the input guys, since I'm gonna spend a bit of time reading about a lot of stuff. Even without a screen I guess one thing i could do to test, make a row of LEDs on the top and bottom of the view, and one on the left and right. Have them light up in a manner that if you crossed them that'd be where the crosshairs would be (hypothetically). Then after programming the arduno to play battleship for me, try aiming around. Don't have that many LEDs on hand though and I haven't got my personal arduno yet (i don't think my boss would like me bringing my airsoft guns into work either). I'd like to see any other suggestions of arguments people may have.

9

Nikarus:
nice call on the OLED display (that would be the ultimate of what I'd want to do, but those probably cost a lot more then I'd be willing to pay)

Actually, they don't cost that much off chinese suppliers on Ebay (I bought one recently for, IIRC, around $20.00 USD?) - the problem is most of those don't have a very easy way to attach the thin ribbon cable; some suppliers offer breakout boards (mine did - but it was separate from the LCD - I am still not sure how I am going to bond the ribbon cable to the breakout board; the standard way uses a specially heated pressure press - not something typically available in a "home shop" - heck, you probably couldn't even buy one used easily - and if you could, it would be expensive).

SparkFun and others do sell "pre-interfaced" and mounted OLEDs, and they aren't what I would call "expensive" (certainly more than $20.00 USD):

http://www.sparkfun.com/products/9676 - $60.00 USD (not too bad)

4-wire SPI - easy to interface (programming it might be a different thing - but maybe there's a library that would work somewhere).

:slight_smile:

10

Yeah I went and read about those a little after I had posted last nite (probably should have edited the post)
I think for my project righ tnow, jsut to prove the concept I'm just gonna go with a bar of LEDs (like 17 across teh top, and 10 up the sides) is gonna be what I try for right now. Cause its easy to build. Shouldn't be too hard to program the lights to work. Main reason why I guess I can't go with any of these displays is cause they all use the SPI interface. What going with the tri axis gyros on sparkfun, they either work on the I2C, or the SPI. But AFAIK theres only 1 set of pins on the Mega (i think like 50-53) for SPI and 2 pins for I2C which only gives space for the 2 gyros plus regular digital and analog I/Os (more then enough digitals to make the LEDs work, and still have room to play)

On the other hand, if someone could clear this up for me. If I'm not mistaken, the 6 pins on most Arduino models I've seen, the ICSP ones, those are able to be used for a SPI setup. Does this mean that the Arduino can support 2 SPI supported things (so say 2 SPI gyro boards, or maybe more normally an SD card reader as well as an SPI screen) at the same time?

11

Nikarus:
Yeah I went and read about those a little after I had posted last nite (probably should have edited the post)
I think for my project righ tnow, jsut to prove the concept I'm just gonna go with a bar of LEDs (like 17 across teh top, and 10 up the sides) is gonna be what I try for right now. Cause its easy to build. Shouldn't be too hard to program the lights to work. Main reason why I guess I can't go with any of these displays is cause they all use the SPI interface. What going with the tri axis gyros on sparkfun, they either work on the I2C, or the SPI. But AFAIK theres only 1 set of pins on the Mega (i think like 50-53) for SPI and 2 pins for I2C which only gives space for the 2 gyros plus regular digital and analog I/Os (more then enough digitals to make the LEDs work, and still have room to play)

On the other hand, if someone could clear this up for me. If I'm not mistaken, the 6 pins on most Arduino models I've seen, the ICSP ones, those are able to be used for a SPI setup. Does this mean that the Arduino can support 2 SPI supported things (so say 2 SPI gyro boards, or maybe more normally an SD card reader as well as an SPI screen) at the same time?

I2C and SPI are serial bus protocols - you can have a number of devices (something like 126 - though the standard supports up to 254?, on the Arduino it is only 7 bit - the full standard is 8 bit; a couple of slots are reserved, IIRC). Each device is addressable. Now - this is great in theory, but just like everything, there is a catch: Each device must have a different address, or a way to change the address. If the addresses conflict, then you can't use both on the same bus. As long as they don't, or as long as you can change the address on one of the devices to something different, you are good.

12

There are for sure transflective LCDs that are basically transparent. I think the little ones from the nokia cellphones (3310/5110) for example and those are quite cheap.

Don't know about all the focussing issues but if you're young enough maybe...

13

Cr0sh, Currently reading a bit about the addressing and stuff (didn't realise that it supported multiple devices)

Wondering however, would I maybe be better off going with regular 2axis gyros that go into the analog inputs. From what I read, SPI doesn't like long wiring, which for the rig on the gun would probably require about 2-2.5ft of wires from the arduino board. Also it'd be a lot easier to get information from simple analog ports with my current arduino experience then trying to jump in and go for SPI addressing. At the same time IIRC theres a hobby shop near me that sells cheap single axis (yeah ill need a bunch) gyros for model airplanes that are like $5 each. Probably not as accurate as say a IXZ500 but enough to get the project off the ground and have something to show for.

Bill2009, I can look into those but kinda planning until the concept is down to go with a couple rows of LEDs, cause their cheap and they can prove teh idea works. TY anyways. And on the note of focusing. Well when I used to have a camera mounted on my gun, and a little screen mounted on my helmet (it could flip up out of the way but was still annoying) I could focus on that pretty well. So I'm pretty sure an indicator over where the gun was aiming wouldn't be too bad.