We see more and more projects that use custom molds and casting materials. The latest is this custom seven segment display which [Ray74] put together. The idea of making your own LED displays couldn’t be much easier than this — everything but the LEDs and wire is available at the craft store.
He started by making models of each segment out of pink erasers. The lower left image of the vignette above shows the eraser segments super glued to some poster board. The decimal is a pencil eraser, with a fence of wood to contain the molding material. Amazing Mold Putty was mixed and pressed into place resulting in the mold shown in the upper right.
From there, [Ray] cast the clear epoxy three times. Once dried the clear pieces were sanded, which will shape them up physically but also serves to diffuse the light. They were then placed inside of another mold form and an epoxy pour — this time doped with black enamel paint — finishes the 7-segment module. The final step is to glue the LEDs on the back side and wire them up.
This definitely trumps the build which Hackaday Alum [Kevin Dady] pulled off using hot glue sticks as light pipes.
You can pretty much tell that this is an outstretched hand shown on a large grid of 7-segment displays. But the only reason you have to look twice is because it is a still photo. When you see the video below it’s more than obvious what you’re looking at… partly because the device is being used as an electronic mirror.
In total there are 192 digits in the display. To make things easier, four-digit modules were used, although we still couldn’t resist showing you the well-organized nightmare that is the wiring scheme. Each module is driven by its own discrete Arduino (driving 28 LEDs as they’re apparently not connecting the decimal point). All 48 Arduino boards receive commands from a Raspberry Pi which is running openFrameworks to generate the animations.
Now of course the project was well under way before [Peter] discovered a similar display from more than a year ago. But we’re glad that didn’t stop them from forging ahead and even building on the idea. They added a camera to the display’s frame which lets it mirror back whatever is in front of it.
What popped into our minds was one of the recent entries for the Trinket contest.
Continue reading “7-Segment Display Matrix Visualizes More Than Numbers”
[Terry] wanted to come up with a little electronics project for his kids, and also came up with something to keep the wife happy. It’s an adorable 14-segment love letter, pieced together with some leftover LED displays and a bit of solder.
There isn’t a microcontroller anywhere to be seen in this project – all the illuminated segments are tied to a switch, and aside from a few resistors there isn’t much to this circuit. The simplicity means it’s a great way for [Terry] to get his kids involved in electronics.
If you’re wondering why [Terry] didn’t throw multiple Arduinos, shift registers, or LED drivers into the build, consider this: sometimes segment displays can be static. The time circuit prop from Back to the Future (but not this modern recreation) was wired up in a similar manner, as only a few specific dates needed to be displayed. Either way, we’re thinking good on [Terry] for introducing his kids to a soldering iron and doing something special for his lady friend.
If you were growing up in the ’80s this display panel will be instantly recognizable. It’s the time circuit display which [Doc Brown] built into his 88 mph per hour DeLoren time machine. If this still doesn’t jog your memory (or if — *gasp* — you’ve never seen the movie Back to the Future) take a gander at the montage video below.
The thing is, if you look really closely you’ll find this isn’t an exact match. Hackaday alum [Phil Burgess] put together a guide for Adafruit that shows how to build this version. But the movie actually cheated when it came to the month display. In production the month was displayed as alpha characters by painting glass slides. To make that happen here you would need some sixteen segment modules (like in this project). But we don’t mind the change one bit. The nostalgic look stands on its own even if it’s not an exact replica.
We’re sure you’ve figured out by now that this is backed by a dead-accurate real time clock (chronodot) and powered by a Teensy microcontroller board. Which means you can use it for just about any of your timekeeping needs.
Continue reading “Adafruit builds the Back to the Future time circuit display”
These days they’ve been replaced with character LCD displays or even brightly colored graphical displays, but if you’re trying to display data on one of your projects, there’s nothing like the classic red glow of a red seven segment display. [five volts] got his hands on a few ancient segmented displays, but controlling even one took up more microcontroller pins than he was ready to spare. The solution to this problem was to use a shift register and control multiple segment displays with an 8 pin microcontroller.
[volts] is using an ATtiny13 to control six seven segment displays. Each display is mounted on a hand-etched board, with a shift register and a handful of resistors soldered to the back. By having the microcontroller shift bits down the line, [volts] created an extremely easy to interface 6-digit segment display, and the entire device can be expanded even more.
The board files and schematics are available on [volt]’s project page. A great project if you’re just starting out to etch your own boards.
Sure, it’s time to get the countdown clocks ready to ring in the new year, but why limit it to just one night? If you end up building a six-foot digital display you can count down trivial events; like the remaining seconds of freedom before you have to pimp yourself out in that drab cubicle.
This seven-segment display is homemade and boasts six full-sized digits and two smaller digits with each pair separated by colons. You have probably already guessed that the construction was greatly simplified by using LED strips rather than individual components. This is part of the reason for the size of the display. The strips can be cut, but only down to a minimum of 3 LEDs per segment. That explains the small digits, with their larger siblings doubled in size. But there is a benefit to this constraint, it means that current limiting is already taken care of for you.
The main assembly is a wooden frame surrounding two polycarbonate sheets. The LED strips are sandwiched between those sheets, with segment and digit driver buses exiting a one point on the side. The build doesn’t detail a driver for the display but it shouldn’t be hard to find a multiplexing example that will serve the purpose.
One look at this display and you know there’s a whole lot of pins that need to be wired up. Now look at what those display modules are mounted on. That’s right, [Kemley] is using point-to-point soldering to rig up this big display. It sports four sixteen segment modules on top for alpha-numeric information, and eight large seven segment modules for displaying numbers only.
We’re not certain as to how the electronics are arranged. When talking about the 16-segment modules he mentions that all four are in parallel with NPN transistors to switch the common anode of each. That’s easy enough to understand. But when you get a look at the transistor board you’ll see 24 of them in use. He’s included a 150 ohm resistor on the collector of each transistor. It must be set up to only allow one segment of each group to switch on at a time? We’d guess that each segment is divided into two (upper and lower pins are multiplexed separately), which would explain the double set of transistors. As for date and time, an Arduino board monitors a DS1307 RTC and manages the scanning of the display.