Lightbox RGBW Upgrade
2019-Sep-06, Friday 06:25 pm![[personal profile]](https://www.dreamwidth.org/img/silk/identity/user.png){kind=small}
chebeI'm wandering around a supermarket when I spot an A4 lightbox. The kind I see in many bars and youtube videos; backlit with white LEDs, a plastic diffuser, and slots for placing plastic tiles with letters written on them. It's a nice idea, restrained, classy. Requires 6 AA batteries. 6?! That's 9 volts. For 18 white LEDs? I needed to see what was going on inside.
Luckily opening it up was very easy. The lid latches onto the main body, and the latches are visible as stress points in the plastic. Just be gentle and it should come apart intact.
Inside there are three rigid strips, with six white LEDs each. They go via a switch (on the outside) to the large battery compartment. Very simple arrangement. Prime for improvement.
Just snip the wires from the battery compartment terminals, and the switch. Everything else is just hot-glued in and comes away very easily. And if careful with the LED strips they can be kept for a future project.
I got the ruler out and worked out what length of LED strip I'd need to replace the existing strips. I figured for a more even colour distribution I'd increase the density in the strips, but also increase the number of strips. This worked out at 17 LEDs per strip, and 6 strips. Which is just under two metres of Adafruit NeoPixel RGBW LED Strip, 60 LED/m. The sheathing is of no benefit here, so I removed it, cut the strips to size, and soldered them together with silicon wire.
I then put them in the lightbox body, with hot-glue, and soldered up to the existing switch.
But the battery compartment is not only not needed, it now blocks some of the LEDs. It had to go. There are a couple of small screws to be undone, and then it just unlatches like the lid did. The downside is there is now a hole in the case that lets light out. So we want to keep some of the battery compartment, but just about the size of the outside-visible door. And none of the height.
This is where I used a rotary tool/cutter (in the style of a Dremel) for the first time. And all my appendages are intact. Win! Using a spiny disc I cut the battery compartment lengthwise, just past the point where the door stops being visible. Then I cut it down, leaving just the frame necessary to hold the door in place.
This cut down piece can be put back, securely, in the case without obscuring any of the LEDs or casting any shadows. It is also still a functional door, so can be used to get at the wires or microcontroller as needed.
Then finally connect the RBGW LED strip up to a microcontroller, load up the example sketch, and close up the lightbox. Oooh pretty. I have this working as a rather colourful lamp off an Arduino until I can figure out how to get my Feather 32u4 Bluefruit LE working correctly. But it can run off a 3.7V battery, or USB power. Which is a considerable improvement over 6 AAs and 9V. And with so many more colour options!
*edit* Finished in part two.
Original lightbox, out of packaging
Photo by chebe
Luckily opening it up was very easy. The lid latches onto the main body, and the latches are visible as stress points in the plastic. Just be gentle and it should come apart intact.
Inside there are three rigid strips, with six white LEDs each. They go via a switch (on the outside) to the large battery compartment. Very simple arrangement. Prime for improvement.
Just snip the wires from the battery compartment terminals, and the switch. Everything else is just hot-glued in and comes away very easily. And if careful with the LED strips they can be kept for a future project.
Original arrangement inside the lightbox
Photo by chebe
I got the ruler out and worked out what length of LED strip I'd need to replace the existing strips. I figured for a more even colour distribution I'd increase the density in the strips, but also increase the number of strips. This worked out at 17 LEDs per strip, and 6 strips. Which is just under two metres of Adafruit NeoPixel RGBW LED Strip, 60 LED/m. The sheathing is of no benefit here, so I removed it, cut the strips to size, and soldered them together with silicon wire.
Replacement RGBW LED strips soldered together
Photo by chebe
I then put them in the lightbox body, with hot-glue, and soldered up to the existing switch.
Replacement RGBW LED strips in place
Photo by chebe
But the battery compartment is not only not needed, it now blocks some of the LEDs. It had to go. There are a couple of small screws to be undone, and then it just unlatches like the lid did. The downside is there is now a hole in the case that lets light out. So we want to keep some of the battery compartment, but just about the size of the outside-visible door. And none of the height.
Removed battery compartment
Photo by chebe
This is where I used a rotary tool/cutter (in the style of a Dremel) for the first time. And all my appendages are intact. Win! Using a spiny disc I cut the battery compartment lengthwise, just past the point where the door stops being visible. Then I cut it down, leaving just the frame necessary to hold the door in place.
Battery compartment all cut up
Photo by chebe
Battery compartment cut down to door and frame
Photo by chebe
This cut down piece can be put back, securely, in the case without obscuring any of the LEDs or casting any shadows. It is also still a functional door, so can be used to get at the wires or microcontroller as needed.
Trimmed battery compartment frame reset
Photo by chebe
Trimmed battery compartment does not block light
Photo by chebe
Then finally connect the RBGW LED strip up to a microcontroller, load up the example sketch, and close up the lightbox. Oooh pretty. I have this working as a rather colourful lamp off an Arduino until I can figure out how to get my Feather 32u4 Bluefruit LE working correctly. But it can run off a 3.7V battery, or USB power. Which is a considerable improvement over 6 AAs and 9V. And with so many more colour options!
Upgraded lightbox of many colours
Photo by chebe
*edit* Finished in part two.
