Author Topic: So got some parts and have a few questions (radioshack parts)  (Read 4141 times)

Offline Balineseterror

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Okay, so I got the best IR LED they had (1.2 45 degree angle, 100ma part# 276-143) but they didn't have the battery case for a AAA battery. I got an easy push momentary switch for it and all of it should fit easily into a modified whiteboard marker case. However I am wondering if anyone who has used that LED and

1) What power source are you using?

2) Are you using a resistor?

3) To everyone else, any issues I should be made aware of? Have read a lot of threats esp. the 101 one. Going to try for the first time to solder something lol, probably going to put everything together and wait for finding the right power supply and a resistor if I need it.

Thanks in advance



Offline benpaddlejones

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Balineseterror ???
1. Go back to radioshack and get the product data sheet (maybe able to get online).
2. Read http://www.wiimoteproject.com/ir-pens/electronics-101-sharing-my-mistakes-updated-t834.0.html

All your questions and more will be answered!

Enjoy
Benpaddlejones


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Offline Balineseterror

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I did read but I am really confused.

People seem to be fine using 1.5 batteries with LEDs when I read the LED specs it says 1.2 forward voltage so unsure does one need a resistor or not?

Also, it doesn't matter it seems that N, AA, or AAA battery is used except for the knowledge that depending on the battery depends on the life of the pen.




Offline benpaddlejones

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Balineseterror
Other people will be using different IR-LED's which will have different forward voltage. The lesson's I provided are so you can look at YOUR exact setup and calculate what YOU need! I would say even Radioshack to Radioshack may have different IR-LED suppliers.

Given the basic information you have provided (1.5v source & 1.2v IR-LED) yes you will need a resistor. You will need to use your data sheet and Lesson 2 to calculate what resistance is required.

The other option is use a rechargeable AAA/AA as these are usually 1.2v and hence will not require a resistor.

You are correct about the battery size what matters is the source voltage.

Benpaddlejones :-)


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Offline benpaddlejones

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Balineseterror
Just relised you have bene looking at http://www.wiimoteproject.com/ir-pens/my-radio-shack-ir-marker-wii-light-pen-t1027.0.html

I should clarify:
- IR LED will still work when under powered (just gets progressively dimmer as voltage continues to drop)
- IR LED will still work when over powered (just has a shorter life)
- IR LED will last a microsecond when seriously over powered

Using 1.5v with a 1.2v IR-LED will work but will have a shorter life span. This is a problem if glueing IR-LED in place as many makers do.

A 15cent Resistor is a massive time saver.

Ben paddlejones :-)


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