7 Segment Clock - Small Printers 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! https://www.instructables.com/ClockSketch-V7-Part-...

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Yet another 7 Segment Clock. xD

Although I have to say it doesn't look that crazy when watching my Instructables profile. It probably get's more irritating the moment you have a look at my thingiverse profile.

So why did I even bother to do another one? Actually the answer is pretty simple...

While playing around with another project I came up with another way to route the led strip inside the modules. To "test my theory" I just had to build one to make sure it works out as expected.

Another major aspect while designing this was people with very small printers. My other things usually are printable on replicator-style printers and i3-style printers with common bed sizes - this one here requires a maximum of 107mm x 89mm x 23mm, so it is printable on printers like the Wanhao i3 Mini (100x120).

Also this is the first of my 7 segment clocks using led strips with 30 leds/m. The other ones are using 60 leds/m, so this is a bit different.

Each segment is lit by 2 leds, so there's 28 leds inside the double digit-modules and another 4 inside the dots-module. Total 60 leds, no "wasted ones" in between (+32 leds if building the 6 digit version).

The finished clock is 234mm x 93mm x 38mm. (360mm wide for 6 digits version).

This documentation will miss quite a few details, like schematics, power limits and so on. Basically it is exactly the same as my other clocks, like S7ripClock here on Instructables. Please have a look at that one for details, this is using the same electronics and the sketch is based on the same source. Requirements are the same with some differences:

Instead of 9x M3 6-10mm screws you'll need:

12x M3 (8-12mm, I've used 8mm) (20 pcs if building the 6 digit version)

2x M3 (12-16mm, I've used 14mm)

Instead of LED strips with 60 leds/m you'll need:

60x WS2812B leds, 30 leds/m (other things like non-coated etc. apply, read S7ripClock instructions!)

Everything else is identical. Arduino/ESP (experimental) support, schematics, buttons, usage instructions.

Usage instructions/Features on YouTube

Update - 22.12.2020

In case you'd like to build this and do own a printer with a bigger build plate (object: 231.4mm x 85.2mm) have a look at Step 9 before starting to print parts...

To build the clock as shown you will need:

2x Frame_LR.STL

2x Cover_LR.STL

1x Frame_Dots.STL

1x Cover_Dots.STL

1x Diffusers_Dots.STL

2x Diffusers_LR.STL

1x Bracket_A.STL

1x Elec_Case.STL (includes spacer-part, case lid and two "hold buttons in place"-things)

1x Feet.STL

1x Cable_Covers_A.STL

Additional parts If building the 6 digit version:

1x Frame_X.STL

1x Cover_X.STL

1x Frame_Dots.STL

1x Cover_Dots.STL

1x Diffusers_LR.STL

1x Diffusers_Dots.STL

1x Bracket_B.STL

1x Cable_Covers_B.STL

Wall widths are always multiples of 0.5mm, so I recommend printing this using an extrusion width/line width of 0.5mm. Using medium print speeds the total print times are roughly 9.5 hours for all the black parts, 3 hours for the diffusers.

No supports needed, no overhangs > 45° and no bridging or anything that might make this a difficult print. Just avoid "the elephant's foot" ;)

Previews shown are at 60mm/s infill, 36mm/s outer perimeters and 42mm/s for solid infill at 0.25mm layer height using 2 perimeters/outlines/shells.

I recommend using a layer height of 0.25mm on this. When the clock is finished you'll be looking at the first layer at the front, so printing this at 0.20mm or finer isn't really necessary.

Also I recommend using black and transparent PLA for this. PETG will be quite wobbly with thin walls like this.

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Sketch is superseded by v7, link right at the top of this sketch (Update 2021).

Here's some pictures to give you an idea of what's going on inside the modules. When building this it is important to watch the orientation of the parts. The double digits-module (Frame_LR) is the same, just rotated by 180° after printing. So you end up with one module showing "L" at the top, the other one "R".

The dots-module doesn't care if it's rotated, holes will always be at the top left/bottom right.

There's 3 pieces of led strip inside the clock. It is extremely important you put in the strips inside the double digit-modules the same way. So do not rotate them _AFTER_ installing the led strip!

One image shows how the leds are adressed later on inside the sketch (starting at #0).

If building the 6 digit-version an additional part is used (Frame_X). Please have a look at the step below about the 6 digits extension.

Here's a more detailed gallery of how the strip is put inside the double digit-modules (Frame_LR, Frame_X).

You can put in the led strip into the dots-frame (Frame_Dots) in two ways, both do start with Data In at the top of the module. But it will affect connection order, so be careful when soldering the strips together and make sure you're connecting GND-GND, +5V-+5V and DI-DO accordingly.

The last picture is showing two dots-modules. Notice how the strip is routed/flipped and one of them has GND on top, the other one +5V. As long as Data In is still on the top it doesn't matter which way you end up putting them in.

Note:

There's some soldering on these led strips every 50cm. If you want to make things a bit easier use strips with 28 leds where the solder joint is between leds #14 and #15.

Here's a few pictures of the connections between the three led strips.

1. Left module data out is connected to dots module data in

2. Dots module data out to right module data in

3. Wires to connect to the microcontroller later on

4. Power wire

Note:

If using a USB wire like I did you need to route it through the cover before soldering!

At this point this clock looks almost exactly like S7ripClock from the back.

So for schematics, details about buttons/electronics, please look here: S7ripClock

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Please refer to the v7 Instructable for schematics and other important information.

1. Bracket_A in place (symmetrical, so rotating it by 180° doesn't matter)

2. Screws used. The two long ones needed hold the electronics case in place

3. Cable covers: Slide them onto the case

4. Cable covers: This "nose" needs to be pushed in/down a bit

5. Push slightly inwards using your thumb while pushing down with your index finger

6. "Nose"/Snap fit in place

7. Adding feet l/r

8. Done

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Please refer to the v7 Instructable for schematics and other important information.

While the protruding diffusors do look quite interesting (especially when looking at the clock from an angle) this does hinder readability a bit. It's hard to describe and even harder to take according pictures. But you can add some "shield" parts to the digits/dots to get a cleaner look.

The first picture shows everything done according to the instructions so far. If you'd like to you can print 4x shields for the digits and 1x shield for the dots. Simply slide them on, they're a snug fit.

The last picture shows 2 digits with and 2 without the shields (outer/inner ones).

If you want to add two digits to the original clock, here's what you need:

1. Another 8 screws (M3x8mm-12mm, I've been using 8mm)

2. 1x Frame_Dots and Cover_Dots

3. 1x Frame_X and Cover_X

4. 1x Cable_Covers_B

5. 1x Bracket_B

6. 1x Diffusers_LR

7. 1x Diffusers_Dots

Some wires and 32x leds are required.

Disassemble everything so you can disconnect the left module from the dots module. Afterwards move the dots module and the right module to the right and insert the new dots module + frame_x. Connect everything like on the previous steps.

Slide on the new cable covers from the right side. Add the old ones as shown.

Upload the sketch after changing "#define LED_DIGITS" from 4 to 6 on top of the sketch. No more changes needed.

Frame_X can be used to build custom displays, there's holes on both sides to route the wires.

If you want to build this clock and your printer is able to handle somewhat bigger objects you might want to give these two parts a go. It's the three frame parts and the three cover parts merged to single parts. All the other parts are the same.

So instead of 6 parts (3x frame, 3x cover) you end up with 2.

There's also two cutouts in the center walls so you don't have to route the wires through the small holes before soldering (usb/power still has to be routed through the cover, though).

Note:
I cut away 1mm from the left/right side on this one to reduce size as much as possible. Using the merged parts the clock can not be extended to 6 digits later!