Saturday, 15 January 2011

Focus, focus, focus

I've been trying to optimise the focus of the Milestag IR beam today. At first I thought the best way would be to observe the beam, and try to get the brightest dot at the furthest distance.

To achieve this I created this unholy device:

This is a super sensitive IR camera with a battery powered CCTV alignment monitor + the Milestag IR focusing section of my gun with faux reload and trigger switches.

My idea was to see how far I could get the beam to be a minimum diameter.

It worked very well, except that at the distances I want I could hardly detect the IR light on the small monitor.

Also I looked a bit of a cock as I walked about my street in darkness with this thing.

So I sat back and thought 'what am I trying to achieve?'. Answer: IR reception at maximum distance so I came up with this:

It's the TSOP4856 detector the Milestag system uses connected via a transistor to a LED. When it detects a 57kHz IR signal the LED illuminates. With the aid of a helper I should be able to optimise the IR focus. The further away the LED lights, the better the focus.

Here is the test circuit built up:


Jacksoft said...

Hi, wich lens have you adopted? Where I can find? Thanks! :O

Tony said...

Got lens from Or, check out IR focus tube at comes with a lens from them as standard.