Of course, there’s nothing unusual about using 7-segment displays, especially in a clock. However, [Edison Science Corner] didn’t buy displays. Instead, he fabricated them from a PCB using 0805 LEDs for the segments. You can see the resulting clock project in the video below.
While the idea is good, we might have been tempted to use a pair of LEDs for each segment or used a diffuser to blur the LEDs. The bare look is nice, but it can make reading some numerals slightly confusing.
We’ve seen a variety of oddball 7-segment displays in the past, but this one uses a new material: both for the display and the mechanical mechanism that drives it; cardboard. Yup, the whole thing is made from cardboard, wood and a few rubber bands. [The Q] shows how he put together in this nice video, starting from first principles that show how the segments are made: simple pieces of cardboard painted on one side with fluorescent paint. A piece of wood pushes the element out to blank it, and each element is connected to a cam wheel that pushes the wood in or out.
The really clever bit is that [The Q] mapped digits 0 – 9 onto a matrix for which of the 7 segments is “on” or “off”. He then used this information to create a stack of 7 cams on a central axle. As you rotate the axle, the cams turn, moving the wooding arms. The arms then cause the elements to flip as they count up through the digits. In essence, he engineered a physical decimal to 7 segment decoder, much like the electronic one inside the SN74LS47. The whole assembly is capped by a knob that indicates which digit is currently displayed. If mechanical displays like this are your thing, check out this one made from LEGO parts, or this awesome 3D printed creation.
Continue reading “7 Segment Clockwork Display Made From Cardboard”
There’s something about clocks — sooner or later, every hacker wants to build one. And we end up seeing all kinds of display techniques being used to show time. For the simplest of builds, 7-segment display modules usually get dug up from the parts bin. If you have a bunch of “smart” LED’s (WS2812’s, APA102’s), then building your own custom 7-segment modules isn’t too difficult either. [rhoalt] had neither, but he did have several 8 LED Neopixel rings lying around. So he thought of experimenting with those, and built a ‘Binoctular’ LED clock which uses the Neopixel rings as 7 segment displays.
Each digit is made using one pair of Neopixel rings, stacked to form a figure of eight. All the digits are composed of arcs, so readability isn’t the best but it’s not hard either. [rhoalt] does mention that the display is easier to read via blurred camera images rather than visually, which isn’t surprising. We’re long used to seeing numbers composed of straight line segments, so arc segmented digits do look weird. But we wouldn’t have known this if [rhoalt] hadn’t shown us, right ? Maybe a thicker diffuser with separator baffles may improve the readability.
The rest of the build is pretty plain vanilla — an Arduino Nano clone, a DS3231 RTC, a Lithium battery, and some buttons, all housed together in a laser cut enclosure which follows the figure of eight design brief. And as usual, once you’ve built one, it’s time to improve and make a better version.
Sometimes, a good hack is about using less rather than more. That’s the case with this neat tutorial from [Rahul.S] on driving a 7-segment LED display with an FT232. By using this cheap USB to serial controller, [Rahul.S] was able to drive the display directly without using a microcontroller, which keeps the component cost down.
He’s bit banging an octal buffer connected to the display. You may be surprised to find that the FT232 chips do have enough outputs to make this work. Rather than send serial data number to the display and have a controller convert this into a set of signals that make the number, this conversion is done by the PC, which then sends a signal that directly illuminates the appropriate parts of the LED. By using all of the available output lines of the FT232 (including ones like the RTS/CTS line that are usually used for signalling), [Rahul.S] was able to drive all seven of the elements and the decimal point.
Of course, cynics may argue that it would be simpler to use a cheap serial LCD display. That is true, but there is always something to be said for knowing how to do something yourself rather than letting others do it for you… Continue reading “Driving A 7 Segment LED Display From An FT232”
The supply of Nixie tubes from east European stock piles is still enough to keep their prices down. But once those start dwindling, prices will move north. Besides, if you want to use them, you need to work with high voltage supplies and worry about not getting zapped while trying to debug a circuit. [FilleK] had some time to spare and decided to build a cheaper substitute for a real nixie tube using a regular 7 segment LED display.
We have already seen this hack before, in the Arduino-based ENIGMA replica. But [FilleK] improved on that by adding an extra LED to simulate the radiant glow typical of Nixie tubes. His project log describes the fairly straightforward process using parts that can be found easily. A piece of plastic, painted in a shade of copper and fixed around the 7 segment display, acts as a nice baffle to contain and reflect the ambient glow of the back-light LED. A nice improvement would be to add a random flicker to the background LED. Maybe add an Octal socket (the decimal point had to be nixed though!), and cap it in a proper glass tube. If you’d rather work with the real McCoy, check out our archives.
We can order seven segment displays in red, green, yellow, or blue all day long. One thing we haven’t seen is an RGB segmented display, so [Markus]’ project is really interesting. He took a stock seven segment display and modded it into an RGB display.
After taking a Dremel to the back of the stock display, [Markus] was left with a seven segment light mask. A few SMD LEDs were purchased through the usual channels. The RGB LEDs were epoxied into place on the back of the light mask one at a time. Thankfully, the LEDs came with magnet wire already attached – helpful, since these LEDs are only 1.6mm x 1.2mm big.
With 32 pieces of magnet wire, [Markus] needed some sort of socket. A small piece of perfboard and some .100″ headers handled the job very nicely. [Markus] still has to work on some way to drive the 24 cathode lines his LED display. He’d like an I2C interface, but with something like an individual seven segment display, the footprint of the circuit should be pretty small. If you’ve got any tips, drop them in the comments section. [Markus] is sure to catch them there.
We here at Hack A Day love LED’s, and all things LED related, but one of the biggest problems with LED’s are the small size. We want bigger and brighter, matrices the size of our TV, seven segments as big as a wall and a single white led the size of a baseball, and brighter than the sun!
I was recently commissioned to make a device which uses a pretty large number display, and I went out shopping. The seven segment we liked best was still quite pricey, and would not fit our enclosure correctly anyway. We ended up going a different route, but it really got me thinking… What if you wanted to make something with a fairly large display? And how could one go about doing it cheaply at home?
I first thought about acrylic rods, but no one near me had any of small diameter, or at a decent price. Never mind that I don’t have that many tools on hand, and I could just see me trying to drill out the end of a thin plastic rod using a electric hand drill, and my knees as a clamp. Looking around the HQ I found my stash of glue-sticks. I thought would make an interesting display and it is easy to work with.
Before I knew it I had a working (serial and expandable) 9 inch tall 6 inch wide 7 segment display. I will be the fist to admit, its not spectacular in quality, or brightness, though the display itself did only cost four dollars in material. A quick and easy project, especially if you need a quick scoreboard or large clock.
Join us after the break to see how the display and the controller circuit are made.
