low voltage LED replacement - Page 1
Forum section: electronics / beginners

author: Trebby123
author_rank: Newbie
timestamp: May 17, 2021, 08:12:37 pm
content: HiWe have a night light projector for my daughter which is fitted with LEDs. Unfortunately we are now on our 3rd projector as the LEDs don't last long at all. I'm wondering if it's possible to replace them but can't find/I'm not quite sure what I'm looking for. It is powered by a 5v USB DC charger. There are some photos of the LEDs in the links below. If the LEDs are replaceable I would plan to remove and then solder in new LEDs. Would be grateful for any thoughts as to whether this is possible and where I can find similar LEDs. Please let me know if any more information would be helpful, and thanks again for your help.https://drive.google.com/file/d/1CFFKNGpa6pefwImMtFao6FZbQoziDIV1/view?usp=sharinghttps://drive.google.com/file/d/1FOqPfzEmEPb47u9XC9pm7jFqdZJPkfU_/view?usp=sharinghttps://drive.google.com/file/d/1Zx-7nN9jCXfKoQMGcX6RE7k6i-LeL17H/view?usp=sharinghttps://drive.google.com/file/d/1unFEmqsCCNuU5KTj7aQKjlLT4wpqX2j1/view?usp=sharing

author: Kleinstein
author_rank: Super Contributor
timestamp: May 17, 2021, 08:34:42 pm
content: The LEDs look a little odd. The main question would be the needed focussing / divergence of the light. Another variable is the brightness - this can vary quite a bit between LED types.The LEDs nearly look like they are damaged machanical by abrasion.

author: Trebby123
author_rank: Newbie
timestamp: May 17, 2021, 08:36:57 pm
content: Thanks for your reply.The brightness isn't a big concern to me, but divergence would be useful. Is there a specific type of LED bulb that I should be looking for that will work with this circuit?

author: Kleinstein
author_rank: Super Contributor
timestamp: May 17, 2021, 08:51:57 pm
content: The broken LEDs don't tell much about the required LEDs. It would need mire a photo of the whole product, so one could see the approximate optics used.

author: tunk
author_rank: Super Contributor
timestamp: May 17, 2021, 09:01:21 pm
content: Could look like straw hat LEDs:https://www.eevblog.com/forum/beginners/led-fail-on-magnifying-glass/If you don't mind a dimmer light, you could use e.g. a 25ohm resistor in series.This should increase the LED life.

author: Trebby123
author_rank: Newbie
timestamp: May 18, 2021, 11:03:04 am
content: Thanks for your replies. The product is this onehttps://www.amazon.co.uk/gp/product/B085LZH566/ref=ppx_yo_dt_b_search_asin_title?ie=UTF8&psc=1I'm not too worried about longevity of the LED if I have an easy source to replace them. Is there any way of telling if those straw hat LEDs will fit?Thanks

author: Trebby123
author_rank: Newbie
timestamp: May 18, 2021, 11:08:44 am
content: Do you think this would work as a replacement?https://www.switchelectronics.co.uk/white-5mm-water-clear-led-2000mcd-30

author: Kleinstein
author_rank: Super Contributor
timestamp: May 18, 2021, 11:34:24 am
content: The LEDs look kind of OK, though still a little small angle. One could work around this by mountig the LEDs at slightly different angles.The indensity also does not look very high, but it can be worth a try.

author: Trebby123
author_rank: Newbie
timestamp: May 18, 2021, 11:35:26 am
content: Thanks again - I'll try this and let you know how I get on!

author: EntropyWizard
author_rank: Contributor
timestamp: May 18, 2021, 04:33:06 pm
content: I have seen something like this in the backlight strips of LCD TV's. These are a little bigger but have the clear bead lens:https://www.ebay.com/itm/202720399879. Notice they also have a "concave" lens option as well. I don't know if you can get these unmounted fron the metal core board, but that is probably for heat sinking, which may be why yours are going bad so fast. Maybe you can fit some of these in your device.

author: Trebby123
author_rank: Newbie
timestamp: May 18, 2021, 08:00:28 pm
content: Thanks for your thoughts on this. I'm not quite sure how I would fit this. I'm going to try the smaller LEDs to start with.