"Help!" for: Electronics

[Redshirt]

Electronics Wizards,

My airsoft Spartan Laser project is nearing completion. My electronics package is complete and does everything I've asked of it so far, but I've come to realize that my LED side markers will make me a BB magnet during night games. I'd like to add a selectable lower intensity option for my side marker LEDs. Can I accomplish this with a single higher resistor added up current from my 90 ohm resistors? If so, what formula would I use to figure that value? Is there some other way I should look at this problem?

My marker LEDs are in the upper left corner of this diagram. Only 4 would need to be in the dimmer circuit. The others are inside the BB hopper to charge the glow-in-the-dark BBs and need to stay brightly lit. Thanks for the help.

Redshirt

 

[Statyk]

It's been awhile since my Electrical Tech class in high school, but a higher resistor should do it. I would pick an adjustable resistor myself so I can hand-pick the intensity however needed. May also save you a bit on figuring out a formula for determining a specific ohm resistance.

I apologize if it's not the best advice, but would an adjustable resistor work? (it's like a lever in a semicircle. The more it's turned, the higher/lower the resistance) They use them in dimmer switches for houses as well.

 

[DBmike]

As mentioned above a variable resistor will do the job because then you can just adjust the brightness to your needs. Just from a brief glance at the diagram try one with a 500-1k range but to determine te exact amount you'll need to do the math.

 

[thatdecade]

Any potentiometer (variable resister) will do the job, but a lower value one will give you more control. 100 or 200 ohm

You can use a 1k pot, but only the first few degrees of the knob will do anything. The rest of the knob turn will have the LEDs off.

 

[Katsu]

I hate to ask, but I've been tinkering with a Teensy arduino platform to try and learn some electronics on my own time, and have hit a bit of a roadblock.

I've just gotten a 74HC595 shift register to try and control multiple LEDs, and it's set up to send signals from the IDE's terminal to determine which ones are on, but only the first LED lights up. I am pretty sure it's a grounding problem, but it's becoming a bit of a nightmare, and I am sure it's a very tiny minor issue. The software is sound, and is echoing right and works in simulations, but only the first LED (the left-most green one) will light up.

The wiring is a mess, I only have two colors.

 

[thatdecade]

Couldn't you control that number of LEDs from the arduino directly?

It's fine, can you link me to an example circuit that you based your protoboard wiring on? I can cross check your picture against that. When only the one LED lights up, tells me one of two things:
- Issue with your clock signal
- Issue with your software designated pinouts

 

[Katsu]

I hate to make the call, but I figured it out. I had a bum USB cable that was preventing me from uploading fixes to software.

The big problem was that my breadboard splits the rails on the side into two, rather than having it run the full length of the board, any LEDs on the rails the controller was on worked, but LEDs on the other set didn't receive anything. So I put all the LEDs on the far rail, and linked it to the rail the controller is on, works like a charm now! Thank you though.

 

[thatdecade]

Ah your right, glad you figured it out. Most breadboards are like that.

I add a short wire to connect the rails on mine.

 

[Spartan 010]

I feel absolutely terrible for asking about this again but my computer died and I lost the sites you posted a while back, thatdecade, regarding sound recording. I looked through the forum but seem to be skipping it somehow.

I want to make the Suppressor from Halo 4 and need audio to play only when the button is pressed, but stops when you let go.

I'm sure answering questions over and over again is annoying so I apologize. Thanks again a TON.

 

[thatdecade]

Sure, check out a sound module from electronics123

This is the one I use most often
http://www.electronics123.com/kits-...-Modules/300-second-USB-recording-module.html

 

[misfitjh]

Ok I couldn't find an active "Heads up display" thread so I thought I'd throw this in here. Samsung has a transparent display coming out for their lap tops

so if they could combine that with their flexible displays

then you could make a decent HUD. Just a thought.

 

[thatdecade]

Looks cool. Can you get your hands on one? the display part.

 

[H4xX3r]

HUD

From my experience, a straight display within the helmet wont work very well. whatever you display will be too close to your eyes to focus on, you need to move the focal length away from the visor, or all you'll get is a blurry mess and eye strain.

im working on this at the moment, once i have some sketches drawn up i'll upload them to here and get started with a prototype!

 

[Geodude487]

Motion Activated Electronics

I'm in the process building a life sized Dalek from Doctor Who and what i'd like to do is put some sort of motion activated device in the eye stalk so that when my friends walk past it it's "ears" and eye stalk lights up and it cries out "EXTERMINATE". The main problem is I know zero about any sort of electric engineering like this and have not the foggiest where to start. Any advice would be greatly appreciated.

 

[thatdecade]

H4xX3r, I've been toying with the idea of a visor HUD. I have some plans on paper to make the hud shapes on the visor glow with leds or el sheet.. Wouldn't do anything for you to see, but would look cool for other people photographing you. Lights would be very visible from outside the helmet.
edit: the end plan was to wire it up to a laser tag sensor. So then people could use my laser tag plasma rifle to shoot the helmet and see it go down in health.

GeoDude, are a couple of ways to add motion detecting to your project. The easiest is a light break detector, anyone breaking the beam of light would set off your circuit. The best however is a microwave motion detector, same thing they use for supermarket automatic doors.

For a prebuilt solution, try this. I have one, is pretty neat to load up your own sounds that are triggered by nearby motion. It does have a limited distance (like a foot) and cannot be mounted behind anything (needs line of sight).
http://www.electronics123.com/kits-...-usb-recording-module-with-motion-sensor.html

 

[Spartan 010]

I'm in the process building a life sized Dalek from Doctor Who and what i'd like to do is put some sort of motion activated device in the eye stalk so that when my friends walk past it it's "ears" and eye stalk lights up and it cries out "EXTERMINATE". The main problem is I know zero about any sort of electric engineering like this and have not the foggiest where to start. Any advice would be greatly appreciated.

With thatdecade's help, I found this: http://www.electronics123.com/kits-...H-LIGHT-SENSOR-PIR-FOR-MOTION-ACTIVATION.html

I think it's JUST the thing you're looking for. I want to make a Dalek REAL bad as well and do something similar. I would suggest making it from EVA padding foam. Debatable the best material in the universe!

 

[thatdecade]

Oh yeah, that is even better. Am thinking your can setup a laser pointer on the light sensor. Plus has a PIR like the other one I linked (heat detector).

 

[Geodude487]

Thanks for the direction to head guys I really appreciate it. Hopefully I'll be able to finish this by the end of the year (got a LOT of projects I wanna start with a current WIP that i'm about 1/4 of the way done with). For the EVA foam could I find that at say the local craft store or would it have to be specialty ordered. Also I think I found a video a while back on YouTube on how to build it out of foam from Pep but I'm gonna ask how you guys would tackle it. Would you cut the Pep files out then use those pieces as a template for the foam? (It's something I thought about doing for the Skyrim Armor I was making so I could use it for LARP as well)

 

[thatdecade]

Try asking in one of the pep or foam threads for better advice.
http://www.405th.com/showthread.php/38589-quot-Help!-quot-for-Foam
http://www.405th.com/showthread.php/26848-quot-Help!-quot-for-Papercraft-or-Pepakura

If it were me, I'd use the pep model to split into layers, then cut out each layer as a template in foam. A normal pep print only gives the outermost layer of the model.

 

[BlertZ]

What would be a good LED for the MkVI helment?