A little help needed regarding choosing right resistor, plz...

[Rian Jardrit]

I will build my saber soon, and want to use the electronic 2010 saber soundboard as well (I will make 3 sabers actually, so it will be some sweet practice, since they will be my first ever...).

I've put the buckpuck in my cart, but after reading this topic along the way, that seems to be a no go...

I want the following three LED types with the 4AAA battery holder:

All P4 LEDs:
White: Volt 3.25 Lum 240 mA 1000
Green:Volt 3.25 Lum 182 mA 1000
Blue: Volt 3.25 Lum 38 mA 1000

All with a 2010 soundboards, that I will pick up tomorrow from the toystores in my neighbourhood.

So I take it I have to get the 2.2ohm 5w resistor for all, even though the store says: Select 3.3 Ohm 5 watt resistor OR 1000mA buckpuck for Seoul P4 White, Green, and Blue?

That brings me to the transistor... you 'americans' get it @ radioshack... but I am a simple dutchy from the Netherlands and don't have Radioshack here! :P
The ones ya'll mention is the BD242 and the TIP42G PNP as being the right ones.

I can (and will)get mine @ conrad over here (http://www1.conrad.nl/scripts/wgate/zcop_nl3/~flN0YXRlPTQwMDc2NjU5Nzk=?~template=PCAT_AREA_S_BR OWSE&glb_user_js=Y&shop=NL2&p_searchstring=transistor&s_haupt_kategorie=&zhmmh_area_kz=&p_init_ipc=X&p_page_to_display=DirektSearch&~cookies=1&scrwidth=1440)!

This site doesn't have the TIp42G but they do have the BD242 (http://www1.conrad.nl/scripts/wgate/zcop_nl3/~flNlc3Npb249UDkwX05MX0IyQzpDX0FHQVRFMTM6MDAwMS4wM Dk4LjU2YmVlMjM5Jn5odHRwX2NvbnRlbnRfY2hhcnNldD1pc28 tODg1OS0xJn5TdGF0ZT0yNzI1NzYwOTE=?~template=PCAT_A REA_S_BROWSE&mfhelp=&p_selected_area=%24ROOT&p_selected_area_fh=&perform_special_action=&glb_user_js=Y&shop=NL2&vgl_artikel_in_index=&product_show_id=&p_page_to_display=DirektSearch&~cookies=1&zhmmh_lfo=&zhmmh_area_kz=&s_haupt_kategorie=&p_searchstring=bd242&p_searchstring_artnr=&p_searchstring_manufac_artnr=&p_search_category=alle&fh_directcall=&r3_matn=&insert_kz=&gvlon=&area_s_url=&brand=&amount=&new_item_quantity=&area_url=&direkt_aufriss_area=&p_countdown=&p_80=&p_80_category=&p_80_article=&p_next_template_after_login=&mindestbestellwert=&login=&password=&bpemail=&bpid=&url=&show_wk=&use_search=3&p_back_template=&template=&kat_save=&updatestr=&vgl_artikel_in_vgl=&titel=&darsteller=&regisseur=&anbieter=&genre=&fsk=&jahr=&jahr2=&dvd_error=X&dvd_empty_error=X&dvd_year_error=&call_dvd=&kna_news=&p_status_scenario=&documentselector=&aktiv=&gewinnspiel=&p_load_area=$ROOT&p_artikelbilder_mode=&p_sortopt=&page=&p_catalog_max_results=20).

So, CAN I, with your experience, using the three P4 LEDs, 4AAA holder, a 2.2ohm 5w resistor and the BD242 transistor make my lightsabers work?

Getting a bit dazzled by all the text in this topic... (and its kinda late -_-')

Anyone want to comment on this, in order to kick me in the right direction?

*EDIT: After carefully reading the following page (http://forums.thecustomsabershop.com/showthread.php?t=11296), I had done some calculations: I came up with a 1.5ohm 5w resistor, by calculating the values and using the LED Resistor Chart from the shop... Again... am I in the right direction here, or am I going downhill even more?!

I have posted this as a reply, in another thread: 2010 Electronic Lightsaber w/ DVD Tutorial.

The thing is... I need to know if I am in the right direction regarding the resistors that are needed for 2010 Hasbro electronic soundboards? Because first I thought Buckpuck because I use the P4 LEDS... then I had read in this thread that I would need 2.2ohm 5w resistors... but with my own calculations with my item setup... i come with the 1.5 ohm... PLEASE HELP if ya'll can! I would really appreciate it, cause I'm SOOO ready to order my parts... but I have to order the right stuff ofcoz! ;)

[RevengeoftheSeth]

V= 6V-3.25V = 2.75 (this is the extra voltage running through your line)
I=1 A (1000 mA) (this is the current)
R = 2.75/1 = 2.75 ohm (this is the required resistance to keep your electronics from dying)

Watts = 2.75 minimum (P=V x I) (Watts is the unchecked 'power' or energy)

So based on these numbers (2.75 ohms and 2.75 watts), you need the next highest (never lower) resistor. In standard resistors, this should be 3.3 ohms and 5 watts. I'm not sure how you got 2.2. I just checked it and that is the correct resistor that I just listed. Your resistor has to be able to disapate the unchecked power on the line effectively to keep your electronics alive. This is usually burned off as heat.

My LED requires 3.85V and 1500mA on a 6v (4xAAA) power supply. So to figure up the resistor, you take 6-3.85 to get 2.15V. Then you take 2.15/1.5 (convert mA to A) to get 1.43 Ohms. To figure up watts, take 2.15 x 1.5 to get 3.23 Watts. The next closest resistor value is 1.5 Ohms and 5 Watts.

I hope this clears up any questions about Ohms Law.

As far as using a transistor + resistor + sound board, you might want to confirm that with someone else. I've never used a sound board at this point in time.

[Rian Jardrit]

Well that was my whole point, the 2.2 ohm... they came up with that in this (http://forums.thecustomsabershop.com/showthread.php?t=10288&page=11)topic...

:confused: "I am so confused..."

[Rhyen Skytracker]

The 2.2 ohm 5 Watt resistor should be fine if you want to overdrive it a little. But keep in mind that when you overdrive LEDs you will lose some of the life of it. Still, with most LEDs having 50,000 - 75,000 hour life spans it won't really matter. Just be sure not to overdrive them too much. One thing I always to with the econo board set up is use a meter to measure the voltage and current going to the main LED. That way you can be sure you have the right sized resistor and the current and voltage going to the LED that you are looking for.

[RevengeoftheSeth]

Well that was my whole point, the 2.2 ohm... they came up with that in this (http://forums.thecustomsabershop.com/showthread.php?t=10288&page=11)topic...

:confused: "I am so confused..."

I can't say I want to sort through 10+ pages of a post to find what you are talking about since I didn't see it in the page you linked, but other factors that can affect what resistor you need will be the length of wiring (wire has natural resistive properties based on material and length) and any other electronics on the circuit (each board/LED/etc absorbs some of the energy off of the line, requiring less to be drawn off by the resistor).

Once you figure up what the 'loose energy' is on the circuit, you can figure out what resistor you need. The examples I gave were for the LED, Batteries, Switch, and Resistor only.

[Rian Jardrit]

The 2.2 ohm 5 Watt resistor should be fine if you want to overdrive it a little. But keep in mind that when you overdrive LEDs you will lose some of the life of it. Still, with most LEDs having 50,000 - 75,000 hour life spans it won't really matter. Just be sure not to overdrive them too much. One thing I always to with the econo board set up is use a meter to measure the voltage and current going to the main LED. That way you can be sure you have the right sized resistor and the current and voltage going to the LED that you are looking for.

Yeah, ok, now I get it again! That was why your 'experiment' with the soundboards came up with the 2.2... Well, a little overdrive is always sweet and I won't have it lit up for long periods anyways. Thnx, again, your explanations are always so clear! :)


I can't say I want to sort through 10+ pages of a post to find what you are talking about since I didn't see it in the page you linked, but other factors that can affect what resistor you need will be the length of wiring (wire has natural resistive properties based on material and length) and any other electronics on the circuit (each board/LED/etc absorbs some of the energy off of the line, requiring less to be drawn off by the resistor).

Once you figure up what the 'loose energy' is on the circuit, you can figure out what resistor you need. The examples I gave were for the LED, Batteries, Switch, and Resistor only.

Heheh I don't blame ya! It is indeed a big topic with a lot of trial and error! But I get it now, I've read trough the 10+ pages again, when I was a lot more awake (the time I've posted it was midnight and had already a busy week gone by due to a wedding of my own that needs some planning :P)

As soon as Tim has all/most items in stock, I'll order my parts for the three sabers I will be building and start fiddling with them. Already bought good new items for soldering (the one I had before wasn't really delicate for this kind of work, due to a bulky solderhead!) and Ill go check for a meter. I wanted to buy it, when I was at the hardware store for the solder items, but it was pricey and want to wait with it untill I have the saber parts!

[RevengeoftheSeth]

Yeah, it kinda stinks having to wait for items some times, but I tell you what - if Tim didn't carry them at all, then a lot fewer people would be out there with the ability to make sabers. :D He's really enabled an awesome hobby. I hope he restocks what you need, soon, so you can finish your builds and share them with the rest of us!

[Rian Jardrit]

well, he informed me about my items and almost all are in stock now, except for the covertec belt clip... I know atleast one saber is complete, and the other two have some small items still missing, but nothing big! So off to ordering VERY SOON!

[Marco]

Hey did you actually figured out the problem with the transistor? I live in Germany and the only one I can get is a TIP42C not the recommended TIP42G... you wanted to take the BD242 right?

I wonder how to find out what type of Transistor to chose and how the actually came up with the TIP42G so I can look for a good alternative out of europe...

[Rhyen Skytracker]

I just got one at my local Radio Shack and it was a TIP42G and I had great results with it. So, I ordered several more of them from mouser.com.

[RevengeoftheSeth]

I use the TIP42G as well that I got from my local RadioShack, and then between the TIP42 and the LED, I used a 1000mA buckpuck from the TCSS store.

[holloway]

I'm sort of in the same boat here, trying to do a white P4 with a 2010 Obi-Wan Hasbro board. I'm so close to having all my parts, but I'm at a loss for if I should go with a BuckPuck or a resistor.

I used the calculator on the TCSS site and it says I have two options: the 1000mA BuckPuck or a 3.3ohm 5watt resistor. Based on the big 30-page Hasbro 2010 topic, seems like a resistor is working just fine for most people and provides plenty of brightness, especially if it's overdriven with a 2.2ohm 5watt resistor like some of you have pointed out.

I really don't want to spend the money for the BuckPuck if I don't have to... so can someone just set my mind at ease and tell me if the resistor would be fine for my setup?

P4 White - 4AAA (6V) - TIP42G transistor

Thanks so much in advance. I'm so close I can taste it!

[RevengeoftheSeth]

A resistor will work just fine. I used a buckpuck because I had one laying around.