PIX 2015

AF Light for the E-PL1

Started Aug 7, 2010 | Discussions thread
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AF Light for the E-PL1
Aug 7, 2010

You might remember sometime back, I posted about an AF light I made for my E-PL1.

It is supposed to be used in dark environments to focus, and then it turns off automatically for the shutter and flash actuation. It also has a mode for continuous light, which is less impressive but handy for video or a poor man's flash. It runs on two 3V watch batteries and makes it 1000% easier to get an AF lock indoors in dim lighting. At the same time, it doesn't effect the image because it turns off automatically while the exposure is happening. I use it on my E-PL1, but it should work on ANY camera that triggers its flash shoe before an exposure.

After some research, I've determined that the market is just not big enough to make any substantial money off of the development of such a product. It would have to be marketed to people with small dslr cameras that have flash but don't have an AF light and have a flash shoe. With upfront costs in the tens of thousands, it's too risky of a venture for myself for very little reward.

That means I'm going to release the plans like I promised to you guys. Bellow is the circuit diagram of the device and an image of the components before I encase them in epoxy.

SW1 and SW2 are actually encompassed by a single three position switch (off,auto, always on). The device mounts in the flash shoe of your camera and connects to the center pin and the ground (the side of the flash shoe). I'm not 100% sure, but the trigger (tr) may have to be wired to the opposite side of the battery than to what is shown (it varies between 555 timers, I think). You can have one or more LED's connected in parallel for the light source, but I hit the maximum current the batteries could deliver at three 3mm super-bright LEDs. You may think that 6V is too much for the LED's but the voltage actually drops during operation.

So the circuit is epoxied to a flash shoe cover with the appropriate electrical connections going through the center of the cover and connecting on the side using springs and exposed wires. The circuit in the epoxy make a coin shaped disk slightly larger in diameter than the batteries. Battery terminals are then made out of strips of flat metal on top. I then cap the entire device with a rubber 3/4" pipe cap that has been cut to length with notches cut out for the LED's and the switch. You can use a set screw to keep the cap connected to the circular epoxy base on top of the flash shoe cover. Depending on your 555 timer, you can get away with using one 3V battery, but the current it can output will be limited. You can get the parts for this from almost any electronics store.

Let me know if you have any question. Have fun building!

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