Introduction: Lazy 7 / Quick Build Edition

Update - 2021/07/15
Sketch v7 available. I also recommend having a look at the notes about electronics when building one of my things!


Yes. Another one. I'll copy/paste the infos I've put up on Thingiverse here, this documentation is only really needed for the led strip routing.

Recently I published the 7 Segment Clock - Small Printers Edition, the first 7 segment display I built using led strips with 30 leds/m.

One thing that wasn't really possible was using a single led strip for the whole clock, like Lazy 7 / One.

But Lazy 7 / One does require lots of material and is not really something you're going to print within a few hours.

Then I remembered I only had published one 7 Segment Clock using a vertical layout, the Retro 7 Segment Clock - SE. And I'm not really a big fan of that one. The "open frame" design doesn't help readability in my opinion and it doesn't feature dots between HH/MM.

This is the result. Some kind of mix between the SPE and L7/One. It's a bit tricky coming up with reasonable names - but at least I'll try to stick to "Lazy = Single Strip", just like inside the Lazy Grid Clock v2 ;)

This one requires a printer with a build size x/y of at least 179.5mm x 107mm, Z max is somewhere around 20mm.

There's 2 leds inside each segment. 4 digits = 28 segments = 56 leds. Adding the
two dots (2 leds each) we end up using 60 leds, no "wasted ones".

I did several changes to (hopefully) make it fit on printers like the Prusa Mini. The goal of this thing was to make it an easy and fast print and build - so slicing everything down to small parts again would have somehow defeated one of the design goals...

Step 1: Printed Parts / Settings

Wall Widths are always multiples of 0.5mm, so I strongly recommend using an extrusion width/line width of 0.5mm when slicing/printing this.

I recommend printing everything except the diffusers using black material.
PETG will be quite wobbly on thin parts like this.

Material requirements:
ca. 150g black PLA
ca. 50g transparent/natural PLA

There's some screenshots of the previews at 60mm/s base/infill speed, 36mm/s outlinesand 42mm/s solid layers. Layer height is 0.25mm, 2 shells/perimeters.

Avoid elephant's foot on the frame part. It will make putting in the diffusers harder. All parts are chamfered towards the build plate so this shouldn't be too much of a problem.

I've started using Cura (4.8.0) more frequently ~10 days ago. So if you're interested in having a look at the settings I've been using to get the fuzzy skin on the outside and grid infill on the first layers, have a look at the Cura project file (L7-QBE-Frame.3mf).

Also added the project file I was using for printing the diffusers (L7-QBE-Diffs-All.3mf).

Step 2: Requirements / Instructions

Electronics are the same as on most of my other things. So for schematics and/or details please have a look at the instructions of those:

Schematics, notes about buttons and required parts (except screws and led strip):

ClockSketch v7

The led routing is close to this one, so if you're looking for more pictures of that:

7 Segment Clock - Small Printers Edition

There's also quite some info on the Retro 7 Segment Clock over on Thingiverse.

It's based on the same sketch as the other ones, so features/instructions from this video are also valid for this one: Features/Usage Instructions

Required Parts

To build this clock you don't really need that many parts. Apart from the electronical components (see S7ripClock documentation) you will need:

2m of led strip, WS2812B, 30 leds/m, 60 total

(other restrictions apply here, too. Like no coated/waterproof ones, thin ones only)

8 screws, M3x8-12 (M3x10 min. for the case screws when using optional feet)

Printed Parts

1x L7-QBE-Frame.stl

1x L7-QBE-Frame-Cover.stl

2x L7-QBE-Diffs-Digits

1x L7-QBE-Diffs-Dots

1x L7-QBE-Elec_Case.stl

1x L7-QBE-Elec_Case-Add.stl (Spacer, Button Bars and Cover)


1x L7-QBE-Feet.stl

4x L7-QBE-Shield-Digits

1x L7-QBE-Shield-Dots

A comparison using the shields vs. none can be found in the SPE instructions.

Step 3: Diffusers

The diffusers should clip in easily. There's 4 types of diffusers:

2 small ones for the dots,
4 bigger ones with similar shape for the center segment inside each digit and
2x 12 for the remaining segments.

Step 4: LED Strip Routing - 1

After putting in the diffusers you can still decide which side of the frame should point upwards. So if one of the short sides does look much better than the other one you can decide to put that one up or down, being more or less visible on the finished clock.

When starting to put in the led strip it is extremely important to follow the layout shown inthe pictures. We'll start with the upper left digit (seen from the back, upper right one when looking at the finished clock). This is where data in will be connected to the microcontroller later.

Be careful when bending the led strip, you don't want to rip off components by accident.

Step 5: LED Strip Routing - 2

After the first digit we will put one led inside the left dot and continue downwards, working our way through the second one (lower left).

Step 6: LED Strip Routing - 3

Now it's time to put in the second led for the left diffuser, the first one on the right diffuser and the ones for the lower right digit...

Actually we're now just mirroring what we've done before... ;)

After the lower right digit the second led to the right diffuser is added and we'll work our way through the last digit (top right).

Step 7: LED Strip Connections

Adding 3 wires to the start of the led strip, +5V/GND/DIN which will be connected to the microcontroller later on, power to the end of the strip.

When adding the power wire/usb wire do not forget to push it through the holes inside the frame cover and the electronics case first!

I know this does look very close. But in theory all the ends (A, B and blank contacts on C) should be too far apart to touch each other. You might want to add some shrink tube or a drop of hot glue to keep everything seperated - but it shouldn't be neccessary if done like this.

Step 8: Assembly

Put in the 6 screws for the frame/border and route the power/usb wire as shown.

For electronics/schematics please look at the documentation linked above, this is exactly the same.
Two push buttons, an Arduino, RTC and a led strip connected to d6...

If you're going to use the optional feet:
They're mounted using the case lid screws (M3x10-12 recommended), there's a picture with and one without them in the gallery.