I don’t like Olight. They sell overpriced flashlights with proprietary batteries and cool white, low CRI LEDs. Also they are not really mod friendly because of glue, potting and press-fitted bezels. And there are even more reasons why I don’t buy Olight products.
A few weeks ago the S1R Baton II was available for a reduced price during Cyber Monday sale on Amazon. There was also a coupon that was valid at the same time. Long story short: I ordered the Olight S1R Baton II for only 20 €. First with the intention to sell it (for a slightly higher price), but then I noticed that many other people had the same idea: eBay and classified sites are full of these Olight products (“original, sealed packaging” for original full price). Well, now I have this flashlight that I don’t want, what can I do with it?
A few words about this flashlight (and most other flashlights from Olight): One of its features is the magnetic charging system (which is quite nice, but not as convenient as a USB charging port). This is also the reason why Olight requires proprietary batteries which have both negative and positive contacts on the same side. While some models have the unique feature of a firestarter, most models have a protection circuit that limits the current of the exposed contacts (in the case of the S1R Baton II the current is limited to something between 1.5 and 2 mA).
This brings us to my idea: We have a 2 mA constant current source, exposed contacts and a magnetic tail. What could you possibly do with this… Of course: Aux LEDs!
First I riveted a metal washer to a perfboard using a hammer and small pins. This is much stronger than glue and also creates a via to the other side of the perfboard. Then I soldered two red SMD LEDs to the board. They are connected in parallel between the rivets and a tiny spring in the middle. The center is negative. To protect the LEDs and hide the conductive parts I glued a piece of thick plastic with two holes and a hollow inside to the board.
This aux LED board has several interesting features:
- Simple user interface: To turn it on just stick it to the end of the flashlight, to turn it off just remove it.
- Fully regulated: The current source is fully regulated and the low Vf of the red LEDs allows them to run until the LVP of the battery kicks in.
- Adjustable: Don’t like red? Use green LEDs! You can simply replace the module to get a different experience! You can even use an ultra low power microcontroller to do fancy stuff!
- Inexpensive: I’ve spent less than $1 for this project and only some basic tools.
It’s not pretty, it’s not really practical. This is just a prototype and only for the fun. But it might be the beginning of very interesting projects with modular flashlights.
Btw: This is also the reason why you shouldn’t stick the flashlight to a metal surface while it is not in use. It will slowly drain the battery (probably negligible while the main LED is switched on). It would have helped to lower the center contact one or two millimeters.