EEVblog #67 – Hacking the Princeton Tec EOS LED Headlamp with a Cree XPG - Page 1
Forum section: electronics / general

author: TheDirty
author_rank: Frequent Contributor
timestamp: March 09, 2010, 11:40:32 pm
content: Cutter is pretty expensive.I can get Cree XRC's Warm White from Digikey for $6 USD or cool white for $5 USD. Do you think they would work with these 20mm stars?http://www.dealextreme.com/details.dx/sku.4512Ha. I remember posting about the EOS long back when you talked about the Princeton Tec flashing bike light.

author: EEVblog
author_rank: Unknown
timestamp: March 10, 2010, 12:21:05 am
content: How is cutter expensive?They are US$5.40, or US$6.50 for the 20mm star mount R4 bin I used.Dave.

author: TheDirty
author_rank: Frequent Contributor
timestamp: March 10, 2010, 12:37:24 am
content: I realize I was looking at the XRC's on the Cutter site and not the XPC's. Of course now their website is dead and I can't check it out.Quote

author: TheDirty
author_rank: Frequent Contributor
timestamp: March 10, 2010, 02:36:11 pm
content: I still don't get that. I get $6.50 for the LED itself XPCWHT-L1-WG0-P4-0-01 + $1.43 to be mounted on a 20mm Star MCPCB. What am I doing wrong?I remember first contemplating pulling my EOS apart, but I hesitated because I'm not certain how to reclose it after I've drilled out the plastic. What did you do to reclose it? Just a bit of epoxy?

author: Simon
author_rank: Unknown
timestamp: March 10, 2010, 06:07:43 pm
content: I got the impression that it will sit back in place and the battery cover will hold it all in place

author: TheDirty
author_rank: Frequent Contributor
timestamp: March 10, 2010, 06:10:03 pm
content: I think you're right. Unfortunately my 2 1/2 year old likes to put it on and run around with it on his head, so I can't find it right now.

author: shawn01
author_rank: Newbie
timestamp: March 11, 2010, 05:21:32 am
content: DaveDuring you final test of the headlamp you did not mention which setting you were using for the comparison. You also mentioned previously, The output current for the high setting was increased to 400ma. Could you please let me know which setting you were using when you shined the lamp in the garage/outsideThanks

author: TheDirty
author_rank: Frequent Contributor
timestamp: March 11, 2010, 01:07:04 pm
content: I think it is safe to say that he was using the max setting, as that was the setting he was modding.I still haven't found my headlamp. Kids are a pain.

author: TheDirty
author_rank: Frequent Contributor
timestamp: March 14, 2010, 02:07:07 am
content: I found my headlamp and took it apart.I also found a link on the candlepower forums for the XPG on cutter. For some reason it gives me a better price than when I just navigated through the website.http://www.cutter.com.au/proddetail.php?prod=cut937So what bin should I be getting? I'm not familiar with the bin number and what they mean in terms of light colour. I think I want an R5, but there are three choices in R5.XPGWHT-L1-1B0-R5-0-01XPGWHT-L1-1C0-R5-0-01XPGWHT-L1-1A0-R5-0-01I think 1A is the warmer colour and a little more expensive. If so, it's the one I would want.

author: Simon
author_rank: Unknown
timestamp: March 14, 2010, 07:16:04 am
content: if they give the colour in kelvin it's 5000 K for daylight, 2-3000 will look yellowy

author: TheDirty
author_rank: Frequent Contributor
timestamp: March 14, 2010, 02:17:16 pm
content: Looking closer at the binning documentation the 1A, 1B, 1C is not a colour temp level, but a chromaticity level that's measured in CCx and CCy coordinates. As far as I can tell the 1C is actually lower on the colour temp range.

author: TheDirty
author_rank: Frequent Contributor
timestamp: April 08, 2010, 01:19:55 am
content: Okay, Dave. My package came from Cutter and my friends bought a couple of EOS's as well, so I have my old EOS and their newer ones. The newer one seem lighter than the old. Not as sturdy.What value did you end up with for R12? I did some experimentation with just adding resistors on top of the R12 to lower the value. I have no real problem sacrificing an LED or even my older EOS to see how well it would work. I tried 1 Ohm, then 0.5 Ohm on top and it brightened it up pretty well. I then went crazy and tried another 0.33 Ohm sense resistor, effectively halving the value. It was pretty bright and I was going to do some measurements of the heat output, but going that low, I started to get a high pitch whistling from the board, so I gave up on that. I'll probably stick with the 0.5, but I need to make some actual measurements to make sure I'm not going to kill anything long term.

author: EEVblog
author_rank: Unknown
timestamp: April 08, 2010, 02:49:51 am
content: In the end I just used the old resistor, as I was happy with the light increase by just going with the XPG.In the video I think I used a 0.47ohm in parallel.But the comparison photos you see were done with the original resistor.Dave.

author: TheDirty
author_rank: Frequent Contributor
timestamp: April 08, 2010, 02:59:55 am
content: Thanks. I'm going to go with a 0.6ohm on top of the current 0.33 and see how it goes with one headlamp for a longer term test.

author: Janne
author_rank: Contributor
timestamp: April 10, 2010, 08:59:56 pm
content: Hi,I've been on the lookout for a good headlamp for a while, and after I saw this blog i decided to get the princeton head lamp. I have to say, that even in the factory setup it is quite impressive, and i already think the 38€ i spent to the lamp was well worth it.I also ordered a new led for it, XPG R5-binner, from kaidomain.. Hope it will arrive soon to make the good even better

author: TheDirty
author_rank: Frequent Contributor
timestamp: April 11, 2010, 03:19:16 am
content: I've found the mod looks better on the newer ones than the old. I think because of the slightly frosted lens.The sense resistor is a different value for new and old. The new ones had a 0.33 and the old had 0.25. The only resistors I had larger than 0.33 was 1.2, so I settled on putting 2x 1.2 ohm resistors on top of the current resistor. So far it works well. No inductor squeal.

author: TheDirty
author_rank: Frequent Contributor
timestamp: July 11, 2010, 11:18:59 pm
content: Thread resurrected. Just wanted to show the side to side comparison that I finally got around to taking.

author: saturation
author_rank: Super Contributor
timestamp: July 12, 2010, 11:20:42 am
content: Nice!