Greetings All.

Complete and utter novice here when it comes to electronics stuff so bear with me.

Am I right in thinking that if I have an IR diode (correct term?) that is 780nm, I would need a suitable sensor to detect that exact nm? Or does it go by sensors detecting nm's within a certain bracket? For example a sensor that detects IR between ranges 750nm - 800nm etc?

I have a used RC battle tank that looks like it still has a working IR turret gun, but no IR targets, and would like to get it working by effectively making my own targets for it.

Thanks in advance, J.

 

Welcome to AAC!

There are very few and very specialized optical sensors that are capable of responding to light at one wavelength.
IR sensors that you can easily obtain are designed to respond to light in a range of wavelengths.

When designing systems to work with IR wavelengths one does not rely on detection of that single wavelength.
More frequently, one has to modulate the intensity of the emitted signal, usually with a coded message, in order to prevent false detection.

 

hi eman,
Welcome to AAC.
Yes the plots have a nm spread.
Look here.
https://www.google.com/search?sourc...pAhViWhUIHcsGDSoQsAR6BAgIEAE&biw=1605&bih=910

E

 

Hi.

So the targets that would have originally come with this battle tank would have had sensors (correct term?) that would have detected an IR within a certain bracket? And that further information that you call coding would have then filtered out other IR's to then only respond to 780nm coming from said tank?

Just so I can visualize this in my head, as I'm the sort of person that works better in seeing the physical hardware in front of me, the hardware I would need to get the ball rolling is:

- Arduino
- IR sensor(s) [would they be photo resistors/transistors etc]
- Power source(s)
- Push pull solenoid [for target flipping ability]
- Bread board,
- Resistors (?)
- LED's (?)
- Other stuff (?)

Apologies for the dumb sounding responses. This is all very new to me. I only discovered a few days ago that things called Arduino's and raspberry Pi's even existed!

 

Don't focus on the 780nm wavelength. This has little to do with signal differentiation.

The signal transmitted by the IR device is coded in two ways.
Firstly, it is modulated at 38kHz, typically,
Secondly, it is encoded in a similar fashion such as a garage door remote controller, or automotive key fob.

That is how your TV/VCR/Cable Receiver controller works.

 

Do you know if the IR LED is modulated & frequency ?
What test equipment do you have ?

 

Afraid not. Testing kit = zero. If it's something I would need anyway to build these targets, I can always get some when I start getting all the other bits of hardware needed.

 

hi eman,
I guess you know that you can use the camera on your mobile phone to check the working of an IR emitter.?
Just shield the camera from ambient light and hold the camera near the emitter, you should see a series of white flashes from the IR emitter on the camera.
Try a a test on your home TV remote control.
E

 

Is there any information printed on the tank as where did the 780 n m come from ?

 

Erm.....this is where I have to admit I'm still using my PAYG phone from years ago. No built in camera. Phone still going strong though and it has over a hundred ringtones. Regarding the 780nm, there's no other labels other than a part worn safety sticker on the underside that referenced just the words "780nm" along with other words such as "Ages 12 years and over" "Parental Guidance recommended". There is evidence of more information on that sticker, but it is so badly faded it is impossible to make out any letters. So based on that I'm just assuming the safety label is alluding to the IR thing in the tanks turret barrel being 780nm. There are a few sections on the underside that have little clock symbols with 1-12 etc but I think they are just injection molding marks to identify what month/year they were made.

I'll see if I can pick up a cheap camera phone and give that test a try. Will that determine any of that modulating/frequency stuff?

 

You can use any digital camera viewfinder (not through the lens) to "see" near IR. My old digital camera from 1998 did it just fine.

 

I'm thinking of buying one of those Arduino starter kits, just so I can begin to familiarise myself with how they work. Are there any specific kits that are more geared towards IR, solenoids etc, or will a standard starter kit suffice? Ideally I'd like to get it from here in the UK.

 

There are IR tank battles on the net; Newegg, Infra-Red Laser Battle RC Tank, but not much detail.