A yellow roadworks warning lamp, shining a little more bright than they normally do. On the side there are two black circles, one with a LED display.

Reducing the scope is a version of done. Right?

I’ve been wanting to make this thing for seriously years. For some reason, 10+ years ago this roadworks warning lamp appeared, and I’ve been thinking about what to make of it since then. And now it’s a small 12V powerbank and bright light.

Right side of the lamp, with the caps of the two black circles opened up. Left one is a 12V car plug outlet, and the right has 2 USB-C and one USB-C connector with an LED voltage meter in the middle
Left side of the lamp, with a small toggle switch.

There’s a USB PD thing and a 12V car outlet on one side, and a small switch for the light on the right. The USB PD thing also includes a voltmeter which allows me to check the battery level easily. There’s a small button on it as well to disable it completely. Funny enough, you can push the button through the cover, which makes this nice to just check the voltage.

Preparation

Loose pile of stuff on a desk. Small LiPo battery pack, connected to some 4mm banana plug test cables, connected to the USB PD thing, connected via USB-C cable to a smartphone. USBPD voltmeter displays something like '10.2', and the phone displays 'Charging rapidly'

I did a sketchy test run of the USB thing earlier, and it does fast charging on my phone, which is neat. Need to check whether it could charge my laptop, but that’s for later. I also need some testing adapter for the XT60 connector. Come to think of it, there’s one in my charger for them 🤔 but interestingly enough, 4mm banana plugs work sometimes, depending on the plug.

Lamp holder

Sides of the lamp part removed, revealing a blue 3D printed post with a G4 (halogen) lamp socket on top, and an LED bulb plugged into it

Now the lamp is a thing I’m a bit proud of. Designed and built this a long long time ago, it’s a 3D printed holder for a G4 12V socket, so a G4 12V LED can be placed right in the middle of the lens of the lamp. Normally these things have tiny LEDs but that’s no fun, we want to shine bright. And now we do ☀️

Electronics inside

Inside view of the base, showing some cables, the fancy clamping wago connectors, and the parts you can see from the outside. One of the black circle thingy, the 12V car plug socket, is not connected yet.
Same inside view as before, but with the battery in the base as well, a small 3S LiPo pack.

The insides are simple, just some wires and wago clamps. the 12V outlet isn’t hooked up yet, but that should be fairly straight forward, just need to crimp some connectors. Battery for now is that same 3S LiPo pack you saw in the test setup, which gives us technically a bit less than 12V on average, but those 12V are more of a recommendation anyways in a car…

Now, why reduction of scope? Well, I wanted to have some fancy charging and other circuitry in this. Initial plan was to design my own solar charger for this, with a nice OLED display and all. But I just wouldn’t get around to it.

So a few months ago, I found this USB PD thing with the volt meter, which takes away one of the objectives of the fancy OLED stuff: voltage monitoring.

Then I found some 3S MPPT solar charge controller board for next to nothing. And I decided to break this project down a little bit.

First iteration now is to make it light up, and we got that now 💪

Next one will be to add the solar charger, and proper battery. I did build a 3S2P 18650 cell holder with BMS, but it has disappeared in my office… But we’re in the process of cleaning so it cannot be that far…

So it does work as a lamp for writing but you shouldn’t look into it, and it lights up the rest of the room a bit too much 😅 (Absolutely not surprising at all given the lens and the original purpose of that thing. It’s still a bit funny though 😬)

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Post by @tiefpunkt@social.tchncs.de
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