Laser dalek!!

[Bald head]

Hi everyone, first off let me say I'm new to this site and I'm not very good with electronics, as you are about to find out!! I have a rather superb 18inch r/c dalek which is also voice interactive and really quite good, it has a 'gun' with a blue LED at the end of it, when the dalek says exterminate the LED lights up, I also have a green laser pen which produces a superb bright beam, I thought it would be fantastic to join the two up, the dalek says exterminate and a bright green laser appears, but although trying a few different methods I can't get it to work, I've used a multi meter on the dalek, it puts out 3.0v when it wants to exterminate, the laser pen uses two 1.5v AA battery's, but according to the multi meter the battery's put out 1,800 MA and the dalek puts out 0.01 MA, I was thinking of using the battery's to light the laser and having the circuit broken with a relay or transistor which would use the power from the dalek to join the circuit when it says exterminate, but to be honest I'm no electronics expert, does anyone know of anyway it can be done? any help would be fantastic, cheers!!!!!

 

[davenn]

hi there
welcome to EP

how exactly did you measure the current from the batteries ?

Dave

 

[Bald head]

Hi dave, what a great site! I put the battery's in a proper battery holder with the positive and negative wires already attached, then I just used the multi meter, do you think this is a realistic project? Or am I just dreaming? Cheers for your help!

 

[Arouse1973]

Kris this is one for you

 

[Arouse1973]

Hi dave, what a great site! I put the battery's in a proper battery holder with the positive and negative wires already attached, then I just used the multi meter, do you think this is a realistic project? Or am I just dreaming? Cheers for your help!

Hi
Yes I would think its no problem. Just waiting for our resident Darlek expert Kris to come on line.
Adam

 

[davenn]

Hi dave, what a great site! I put the battery's in a proper battery holder with the positive and negative wires already attached, then I just used the multi meter, do you think this is a realistic project? Or am I just dreaming? Cheers for your help!

yes BUT how did you connect the multimeter ? Do you know that the multimeter needs to be in series with the circuit to measure current ? I seriously doubt that a handheld laser pointer draws 1.8A. more likely a few 10's of milliamps

Dave

 

[Bald head]

I did try to connect the laser directly to the dalek, it worked but very dim, I've now come up with a new idea, if the voltage from the dalek can work a small servo, I could put a metal connector on the end of the servo arm so that when it's operated (the dalek says exterminate) the arm could rest on the broken wires of the laser circuit which will use its own battery's to power the laser, good idea or just silly?

 

[BobK]

Much easier to jus use a transistor as a switch.

Are you sure about your the 0.01mA reading? That sounds very wrong as well. How did you measure this, with the laser in the circuit, I hope?

Bob

 

[Bald head]

Hi bob, yeah I think you are right, I've got the readings all wrong, if I get the correct readings in the next few days I will post them, I think it's better for the the laser to work off its own battery's and have the power from the dalek to operate some sort of switch to join the laser circuit, I did think of a transistor but I really don't know how to wire it up or if it needs anything other than just a transistor, any help would be great, cheers.

 

[BobK]

We have a resource for that:

https://www.electronicspoint.com/resources/using-a-bipolar-transistor-to-turn-a-load-on-and-off.30/

Bob

 

[Bald head]

Cheers bob, I'm gonna get my parts and give it a go, I'm a little confused about wiring the transistor though, the dalek gun has positive and negative wires coming from it, I take it the positive passes through the resistor, but transistors have 3 prongs, I haven't a clue which goes where, plus I've only got 2 wires coming from the dalek

 

[(*steve*)]

Have you considered that having a laser on a toy (especially a green laser from a laser pointer) is a little dangerous?

 

[Bald head]

Hi steve, the dalek is actually a collectors dream at the moment as it was only made for a very short time, i think adding a real laser would add some realism to it and obviously make it much more exciting to watch, but dont worry, the laser i want to use cant burn, sure its not good for the eyes if you look directly at it, the idea is mainly for effect, im 47 and i wont be letting any kids get their hands on it thats for sure!! I think the DR WHO fans are gonna love it if i pull it off, youtube videos to follow if i do!!!!

 

[donkey]

ok so the laser doesn't burn..... burn what?
A simple laser pointer is enough to temporarily blind someone with possible permanent disability.
being a Whovian I love the idea. Davros would be proud that even a miniature version of his creation could at least blind someone. having said that I would not do this for 2 extremely important reasons.
1 Danger Wwill Robinson danger. Lasers, even those little suckers in pens are not something you put on a "toy." damage to the retina is a very real possibility.
2. as you stated this was only released for a short time. as with all items in limited release any modifications lowers its value.

I WOULD however make my own. I WOULD use this one as a mould. I WOULD NOT put a laser on it. I WOULD put a nerf gun on it. I WOULD seek to exterminate all timelords and T.A.R.D.I.S.'s. I WOULD make Davros proud. but that's just me.

Oh and another quick thing to add. I would make this Dalek like the 2005 iteration and give it hovering capabilities... those damn stairs were annoying before.

If you get really stuck show us the circuit, show us where you got your readings from and we could possibly help

 

[BobK]

Using an NPN transistor:

- wire from Dalek to - wire of laser battery
+ wire from Dalek to resistor to base of transistor
+ wire of laser to + of battery
- wire of laser to collector of transistor
emitter of transistor to - wire of laser battery

Bob

 

[Bald head]

Bloody hell cheers bob!!! That's fantastic! You know your stuff! my parts should be here in the next couple of days, I got the weekend off work so I shall sit Down and give it a go, can't wait to see what happens, I'll keep you posted, I feel the only way this is not going to work is if I've ordered the wrong parts (a very real possibility!!) cheers for your help once again!

 

[Bald head]

Bob are you out there? Your instruction worked!! But I still have one problem, the laser that worked was a very low powered red laser, I upgraded to a more powerfull and brighter green laser but now it doesn't work, even though the red and green lasers use the same battery's, I reconnected the red laser and it works again, any ideas anyone?

 

[BobK]

Yep, I am here!

How much current does the green laser need? What transistor and resistor did you use?

Bob

 

[Bald head]

Hi bob, I used a bc548 transistor and a 390 ohm resistor, the red laser is a 5mw output and works fine with the dalek but the green laser is 200mw output, it would look unbelievable on the dalek but just doesn't work even though both lasers use the same battery's, is it a case of changing the resistor and transistor? Cheers for your help bob.

 

[(*steve*)]

The green laser is very dangerous to eyesight. This is not only from the green laser beam but also from the IR that is doubled to create the green light.