DIY torch hosts and what you can put into them
Posted: Fri Sep 18, 2015 5:56 pm
One bit of gear you can buy from places like Fasttech, Dealextreme and other Chinese 'lectronics places is flashlight "hosts" or bodies. These have pretty much everything except the LED and driver circuit. So you can pick the right sort of host and put your own electronics in.
Want a small pocket torch with a high powered LED in it?
A mid sized thrower?
Something with an unusual LED - coloured, infrared, etc?
You can use DIY hosts to do these things.
The host I'm using is an Ultrafire C10 which is a mid sized torch for a singe 18650 battery or pair of 123's, that makes a decent mid range thrower for outdoor use or gun mounting.
https://www.fasttech.com/products/1618/ ... flashlight
I'm building two red ones for my young bloke's use over summer for shooting bunnies. One to be hand held and the other rifle mounted.
I've used this LED, a red Cree XP-E. You can of course use whatever you want.
https://www.fasttech.com/p/2116101
A 1.4A driver to suit. This will drive the XP-E a bit higher than the recommended 1A of current, but it won't be a problem and is what I normally use with the XP-E.
https://www.fasttech.com/p/1127404
Some plastic centering discs to keep the LED locked into the reflector, which has a big hole for the much larger Cree XM-L.
https://www.fasttech.com/p/1576101
Here's the host consisting of the body, the aluminium "pill" that holds the LED and driver which includes a press fit brass ring to hold the driver board, a positive contact spring for the driver board and a plastic insulation gasket.
Plastic spacer, LED and driver board.
First thing to do is stick the LED to the pill. Many folks will use a thermal glue, TBH I just use a small blob of high temp silicon and it's never been an issue. I roughen the face of the pill and the bottom of the LED board before sticking down.
For some reason, Ultrafire make the pill with a 19mm well in it for the LED. The issue here is that LED's come on 20mm or 16mm boards.... Someone in China knows why they do this, to us roundeyes it remains a mystery. So I use a 16mm board, and carefully centre it by eye. Note the two holes where the + and - wires will feed through. Don't clog with silicone or stick the LED board over them.
Most driver boards are slightly oversized or with little dags or tabs on them where they've been stuck to a large PCB board. You can file them slightly to fit snugly. I've done that, so the board fits the brass ring that comes with the pill, and soldered the + contact spring on.
I've pressed the brass ring into the bottom of the pill, run my power leads through and soldered the red to the + pad and the black to the -. The excess wire just coils up inside the pill when you press the driver board in. At this point you can press fit the board into the pill, screw the lot into the torch and power it up to see if it works. You don't need to put the reflector in to do this.
After I tested that it works, I solder the driver board to the brass ring to keep it in place.
I then pop on the inner centering disc, then the outer gasket that comes with the host.
The whole lot screws into the body - I use a pointy knife to screw the pill in.
Put the reflector on, screw the lens and bezel on.
And we have a red thrower torch.
You could build a throwy white version with this LED:
https://www.fasttech.com/products/1609/ ... -7500k-led
And this driver:
https://www.fasttech.com/p/1122301
Or a high powered version with decent range with this LED
https://www.fasttech.com/products/1609/ ... ed-emitter
and driver:
https://www.fasttech.com/products/1612/ ... t-driver-c
Want a small pocket torch with a high powered LED in it?
A mid sized thrower?
Something with an unusual LED - coloured, infrared, etc?
You can use DIY hosts to do these things.
The host I'm using is an Ultrafire C10 which is a mid sized torch for a singe 18650 battery or pair of 123's, that makes a decent mid range thrower for outdoor use or gun mounting.
https://www.fasttech.com/products/1618/ ... flashlight
I'm building two red ones for my young bloke's use over summer for shooting bunnies. One to be hand held and the other rifle mounted.
I've used this LED, a red Cree XP-E. You can of course use whatever you want.
https://www.fasttech.com/p/2116101
A 1.4A driver to suit. This will drive the XP-E a bit higher than the recommended 1A of current, but it won't be a problem and is what I normally use with the XP-E.
https://www.fasttech.com/p/1127404
Some plastic centering discs to keep the LED locked into the reflector, which has a big hole for the much larger Cree XM-L.
https://www.fasttech.com/p/1576101
Here's the host consisting of the body, the aluminium "pill" that holds the LED and driver which includes a press fit brass ring to hold the driver board, a positive contact spring for the driver board and a plastic insulation gasket.
Plastic spacer, LED and driver board.
First thing to do is stick the LED to the pill. Many folks will use a thermal glue, TBH I just use a small blob of high temp silicon and it's never been an issue. I roughen the face of the pill and the bottom of the LED board before sticking down.
For some reason, Ultrafire make the pill with a 19mm well in it for the LED. The issue here is that LED's come on 20mm or 16mm boards.... Someone in China knows why they do this, to us roundeyes it remains a mystery. So I use a 16mm board, and carefully centre it by eye. Note the two holes where the + and - wires will feed through. Don't clog with silicone or stick the LED board over them.
Most driver boards are slightly oversized or with little dags or tabs on them where they've been stuck to a large PCB board. You can file them slightly to fit snugly. I've done that, so the board fits the brass ring that comes with the pill, and soldered the + contact spring on.
I've pressed the brass ring into the bottom of the pill, run my power leads through and soldered the red to the + pad and the black to the -. The excess wire just coils up inside the pill when you press the driver board in. At this point you can press fit the board into the pill, screw the lot into the torch and power it up to see if it works. You don't need to put the reflector in to do this.
After I tested that it works, I solder the driver board to the brass ring to keep it in place.
I then pop on the inner centering disc, then the outer gasket that comes with the host.
The whole lot screws into the body - I use a pointy knife to screw the pill in.
Put the reflector on, screw the lens and bezel on.
And we have a red thrower torch.
You could build a throwy white version with this LED:
https://www.fasttech.com/products/1609/ ... -7500k-led
And this driver:
https://www.fasttech.com/p/1122301
Or a high powered version with decent range with this LED
https://www.fasttech.com/products/1609/ ... ed-emitter
and driver:
https://www.fasttech.com/products/1612/ ... t-driver-c