Small PHR presentation pointer

I made a small presentation pointer because I did not have anything handy at hand except boring red DX pointers. I don't see myself using a 100+mW MXDL during class either.

The diode is powered by 5 button cells, without driver or resistor. I measured the internal resistance of the 5 batteries together to be 30 ohm and with a load of 100mA the voltage dropped to 4.5V. Fitting this data to a PHR's U-I curve and one finds that it will be very safe. After hooking an actual PHR (COD one) it consumed 50mA. I decided to go with the direct connection and not with an extra resistor because at 50mA the power is low enough for presentations.

[edit]I also added a small 100nF 0603 capacitor to the diode legs to minimize the shock of turning it on.

With new batteries it reached 20mW peak, but after using it for a few minutes, the average power is around 15mW. Compared to actual 5.0mW red it looks just a bit dimmer.

I used (parts of) a pointer I bought on the streets of Akihabara (Tokyo) and I added a paper isolator and o-ring. I reversed the battery compartment and used a spring from somewhere else.






Compared to 5.0mW red.


Smile, anyone?

thats awesome, i bet daguin wants one!

travislikescoolstuff said:

thats awesome, i bet daguin wants one!

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I like around 10mW of violet for lecture. I am also a big fan of side-button type hosts for lecture.

That being said, I am very impressed (once again) by the ingenuity of Zom-B. I like how Zom-B's mind works.

Peace,
dave

I also prefer side-button hosts, and I also wished I could power it by two 10440 or 14550 3.6Vs, but my only side button host capable of having >5V worth of batteries is my only 5.0mW precision red pointer (incidentally takes 10440s). I have lots of empty bullet pointer shells, but they won't fit 5 cell batteries AND a switch (switch could be handy sometimes).

Zom-B said:

I also prefer side-button hosts, and I also wished I could power it by two 10440 or 14550 3.6Vs, but my only side button host capable of having >5V worth of batteries is my only 5.0mW precision red pointer (incidentally takes 10440s).  I have lots of empty bullet pointer shells, but they won't fit 5 cell batteries AND a switch (switch could be handy sometimes).

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I've built a few presentation pointers using the PS3 diode. I wonder how they would like the button batteries? . . . . . . hmmmmmmmm . . . . . .

Oh yeah, +1 for creativity

Peace,
dave

I had two PS3 diodes dying at 86 and 133mA respectively, and one live still happily at 75mA (that's the one with the lowest kink :'() I have no record of the voltages at each current though but I guess they'll like it. It can't be that different, like 4V or something

Zom-B said:

I had two PS3 diodes dying at 86 and 133mA respectively, and one live still happily at 75mA (that's the one with the lowest kink :'() I have no record of the voltages at each current though but I guess they'll like it. It can't be that different, like 4V or something

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For use as lecture pointers, I have never taken one above 40mA (2 @ 10440 batteries).  That gives me between 9-15mW.  Brighter than that, I would worry about specular reflection into the audience.

Peace,
dave

My creativity has not depleted yet.

I was pondering how I can always carry it with me without it getting too dusty or turning on by accident. The front was sawed off to gut it and the aperture was reamed to let more light through in the original pointer. I finally figured that if I keep it in some sort of container I can take it out when I need it. I could not find a suitable container though.

At some moment as I was walking around while the laser was back in it's original shell (first photo). I was looking for suitable caps. I found that a certain AixiZ back fits almost perfectly over the top. and with some deforming, it fitted perfectly.

The problem of dust was solved but it could still accidentally turned on. When the top is pressed, the module moves backward and the switch presses against the back (this is how it originally operated when the sawed-off top still protruded a lot more).

While I was looking for some kind of ring big enough to fit over the internal module but small enough to fit in an aixiz, I found a conic spring. It worked perfectly. While I was thinking how I would prevent the spring from falling out and getting lost, I bent one end through the hole and back in, and doubled it for a keychain hole. Now I can even use the original keychain

Does that meter read 150mW? :-/

It's in the 0.1mW range. Because the panel meter only has on-board switches for the decimal point, I just decided to not have a decimal point at all.

Yea, 10 MW is fine for lecture!

Jono3289 said:

Yea, 10 MW is fine for lecture!

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Yeah, if you want to vaporize your students

If you're going to use your 10MW(MEGAWATT) laser in school, try to make sure that if the beam hits someone, it hits them in the head. Their death will be much faster and less painful if you vaporize their head first, instead of an arm or leg or something..

and watch out for reflections :

Zom-B said:

I used (parts of) a pointer I bought on the streets of Akihabara (Tokyo)

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I love Akihabara, all the lights everywhere are amazing. I like that you can haggle with everyone over prices too I went about 5 years ago when credit card digital cameras were just coming to be and got one of those, along with some crazy awesome headphones that I still use every once in a while.

nice laser too, very sleek design.

-Kendall

Jono3289 said:

Yea, 10 MW is fine for lecture!

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A big "M" is a billion times more powerful than a little "m"...

Anyways, you're driving that directly off coin cells? Ingenious!

How long do you think those batteries will last with that sort of drain?