Hi All,
After a couple of fallow years, I'm now revisiting an old project of mine to convert some old Oldham headsets to LEDs.  All the old sites I used to source LEDs (Cree XL/XM) and drivers are now either defunct or dollar price only.  Any suggestions on reliable sources for these?
Thanks
Martin

At risk of stating the obvious... http://www.customduo.co.uk/Pitlamp-Module-Fitting/

Thanks
Yes, I could just buy the (excellent) inserts, but having acquired a number of redundant sets, I was fancying a winter challenge of pure DIY - I don't intend these for serious use , as my main light is a Dragon from Mr. Fellows, but more of simple lend sets, and maybe for a couple of other home lighting projects.

Fastech (or summa like that Roy knows)

https://www.fasttech.com/

You pay by PayPal and its converted into dollars no no issues.
To covert an Oldham make a flat plate of aluminium or SWG 22 copper to fit into the lamp after dumping bulb holders. Mount drivers on the rear and LEDs on the front.

Best for low voltage are 7135 based drivers, but beware of silly flashes and strobes. You can remove the anti reverse polarity diode which wastes 0.33 volts (assuming Schottky) off whatever battery is supplying. The drivers are for torches and the diode is to safeguard against silly buggers putting batteries in the wrong way round. Standard diodes waste 0.7V.

Each 7135 gives 350mA, so they paralleled. For a multi mode you will get about 50mA on top off the microcontroller.

Another good supplier is kaidomain, they do a lot of the stuff without the flashes, or you can solder a little bridge to get rid of them.
http://www.kaidomain.com/

If is a 7135 based multimode, you can take one 7135 out of the microcontroller to set a realistic bottom brightness level.

Remember that if you a first timer when you start modding stuff you will start trashing stuff, so best buy in  a few of everything.

Thanks for that, if all goes well, I'll report back - but I'll keep quiet about all the ones that end up in the bin....

Martin

Another good supplier for "naked" LED's is RS components BUT they're generally sold without the MCPCBs surface mount LEDs live on and you'll have to sift through quite a few Cree data sheets to get the correct one (bin, colour, etc.).

Mountain Electronics was great for all your light building needs until they stopped shipping to the UK.

More useful for updating say Scurion LEDs, having a play around and making specialised lights (in my case I wanted very high CRI).

Just found this browsing FastTech

https://www.fasttech.com/p/1122302

The lowest mode is too low you will find, so use a craft knife to take one of the 7135 chips away from the microcontroller, dump the schottky, and resolder as necessary the orphaned chip.

The is another similar one.

I have come back on this thread from the MOSFET controversy on another.

Lamp builders beware the reverse polarity protection diode on the Chinese drivers!

There for good reason, as all these drivers are generic to torches, bike lamps, head torches and whatever, where the user loads in loose batteries. Obviously, nothing to prevent some fool putting them in backwards, hence the diode. problem is that efficiency goes down due to the 0.33V (approx) Vf drop on Schottky Diode. Hope they do use Schottky, not ordinary diodes, they much worse!

So, if say 1 amp is going through it, you loose 0.33 watts as heat. So if not needed, remove.

So, to MOSFETS. If you must have reverse polarity protection you can use a MOSFET wired backwards. So its Drain to voltage in, Source to load. Gate is still either P signal or N signal as appropriate to the diode. N needs gate P, P needs gate N. Credit where its due, I learned this many years ago from Mr Mike.

Now, a question for Chris JC, he is bound to read this.

I have spent hours trawling through data sheets and have found an alternative low Rds MOSFET.
I have been seeing product descriptions on RS Online that do not agree with data sheet. Descriptions are giving stuff like Rds = 0.0016 ohms, and data sheet clearly states 1.6 ohms, a bit high for a MOSFET. Data sheet clearly states Ohms not milliohms.
Any ideas?

Of course, this is relevant to their use as a RP protection, it also explains why on a lot of the Chinese off-the-shelf drivers you have massive 40 amp switching diodes.

It does sound like a cockup - it ought to be clear which side has missed off the 'milli' from the other parameters.

The other thing to do is to load the model into LTSpice and do some virtual testing of it.

Which one is it?

Chris.

I just wondered if you had come across this. There were several from same manufacturer. Didn't note the part numbers.
I have actually, found one which fits what I need after a lot of searching. 20 in stock, I ordered 10 of them.
We will get there in the end, it just takes along time

Have you ever read "The Gold Mines of merioneth" Vol 1 by George Hall?
It has a dream by T A Redwin who was a rather unsuccessful gold entrepreneur in the 19th century. Part of it was where he takes gold bearing quartz to a very sceptical  London jeweller

"It must take a skill twix that of a dentist and a watchmaker to get the gold into the quartz"

A bit like what we do with our fine tip soldering irons

royfellows said:

I have spent hours trawling through data sheets and have found an alternative low Rds MOSFET.
I have been seeing product descriptions on RS Online that do not agree with data sheet. Descriptions are giving stuff like Rds = 0.0016 ohms, and data sheet clearly states 1.6 ohms, a bit high for a MOSFET. Data sheet clearly states Ohms not milliohms.
Any ideas?

Click to expand...

I come across this often whilst searching for new parts - data entry errors probably due to not very technical people putting it in. Similar thing with orders that arrive wrong due to no idea of what the picker is picking - some basic training in component identification would be good. It would stop you receiving 2 way pcb headers when you order 28 pin microcontrollers....

Nice to see you Mike, long time.

royfellows said:

A bit like what we do with our fine tip soldering irons

Click to expand...

I ran across this old board I modified whilst looking for something else. We wanted to try a different processor, so I purchased one in a smaller package (BGA), glued it on upside down within the footprint of the old, then soldered on 104 tiny wires running from the solder balls out to the existing pads. Then I built the power / ground network over the top. The solder balls were on a 1mm pitch, 0.4mm balls.

That is my 'fine tipped soldering iron' piece-de-resistance (pun there!!)

It worked.

Chris.