Introduction: Lazy Grid Clock V2

Lazy Grid Clock v2

Welcome to LGCv2, a 7x11 led matrix using a single LED strip.

Update - 2021/11/18

Sketch v7 available. I also recommend having a look at the notes about electronics when building one of my things!

Update - 2020/06/02

Added draft of sketch v6 which can be compiled for nodeMCU/ESP8266. It's been added to Step 6. For details/information please have a look at Step 11 from my S7ripClock.

The idea behind this thing was to avoid soldering multiple led strips like in a classic matrix. For this to work there's 6 leds "wasted" but it makes building the grid much faster.

Basically this is the same as my previous Lazy Grid Clock - it's now finally updated to provide an easier build and use less materials, like screws. As there are some remixes/modifications out there I kept orientation/start point of the grid, so the sketches can be used on LGCv1 and v2.

The Arduino sketch is based on the S7ripClock. So while looking somewhat different the instructions/features from the video are valid for this also.

If you're looking for a bigger grid and don't care about doing some solder work you might want to have a look at my "Grid Clock v2":

Step 1: STL Files and Printing Instructions

Walls are always multiples of 0.5mm, so I strongly suggest using and extrusion width/line width of 0.5mm (no, not recommending a 0.5mm nozzle here!).

At 60mm/s (everything, including outlines/solid infill) it takes about 7.5 hours to print all the parts needed. There's no tricky parts like steep overhangs or bridging, no needs for supports, so it is a fairly easy print.

Some parts only have a single retract per layer (diff grid), others do have some specific cuts within their first 1-2 layers. This is to make printing even easier by avoiding dozens of retracts on the first layer.

The biggest part is 199.0mm x 142.0mm x 23.50mm so it should be printable on common models without trouble.

Recommended print settings:

0.25mm layer height
0.50mm extrusion width/line width
2 shells/perimeters

Step 2: Overview / Notes

Most of the documentation will be pictures only. This is using the same electronics as my "S7ripClock" and this is very close to the old "Lazy Grid Clock". I strongly recommend having a look at the S7ripClock when building this, I've reused the electronics from that one for the purpose of the pictures here... Schematics are exactly the same, only difference being the electronics case mirrored on the LGCv2.


If you have a close look at the pictures later you'll notice I haven't connected the Arduino to the LED strip. That's because I've published quite some things so far and don't want to waste an Arduino on each just for taking the pictures.

Step 3: Required Parts

3D printed parts:




LGCv2_Elec-Case.STL (2x button bars included)

LGCv2_Elec-Covers.STL (2x cable covers included)



= 11 parts total

I recommend printing all except the case/stand using black material to avoid light leaks. The case can be printed from a different color but it should be a opaque one (I chose silver/anthracite).

Other parts:

1x Arduino Pro Mini (5v, 328p) or Arduino Nano

83x WS2812B LEDs, 60/meter strips, 5V, each led individually addressable, 10mm wide(IP65/67, coated/rubberized ones do not fit!)

1x DS3231 RTC module (ZS-042, DS3231 for Pi or similar)

2x 6x6mm push buttons (button length doesn't really matter, 3-6mm will work well)

1x USB cable / USB Wall Charger (500mA min, 1A recommended)

5x M3 screws (length 8mm - 12mm, doesn't really matter. 8mm recommended)

Some wires (AWG 26 min. recommended)

2x 120mm x 188mm diffusive material (I've been using Folex Ink Jet Film, very thin paper or similar will work also)

You will need a working Arduino IDE to upload the sketch. Also you should know about the difference between compiling and uploading a sketch or installing the required libraries. If you're completely new to leds/arduino I recommend working through something like Adafruits Neopixel Guide first.


The sketch is using the FastLED library. So other LEDs can be used but this instructable will not include such modifications. Same goes for using an ESP8266 without logic level shifters and WS2812B.
For RTC communications the DS3232 library by JChristensen is used. So other models are supported (DS1307), I just didn't come across one without massive drift yet... ^^

Step 4: Building the Grid

Orientation is important. So keep an eye for the "x" inside the case, which marks the lower right corner/data in when building this.

When finished and seen from the front this will be x/y 0,0 in the lower left corner.

Start with the led strip/data in as shown. Note the fins on the led frame, there is none on the top of the part.

I highly recommend not pre-cutting a piece of 83 leds. Check where you have to bend the strip and make sure there's no solder joints exactly there.

Add three wires to the start of the strip (+5V / red, GND / black, Data In / green). The USB/power wire is connected to the end of the strip.

Step 5: Assembly

Now it's time to assemble all the parts...

Start by placing the first sheet of diffusive material inside the case and putting the diffuser grid on top, orientation doesn't matter on this one.

Next add the second sheet and put the led grid on top of it. Make sure the fins slide in properly, data in is in the lower right corner and that's where the "x" inside the frame is located.

Route wires as shown (upper left screw hole has thinner walls to extend space for usb wire) and put the cover on ("x" on the right side).


After taking all the pictures I decided to modify the cable covers a bit. They're now less obstrusive and orientation should be more obvious.

Step 6: Electronics / Sketch

Electronics are pretty easy. There's only 2 push buttons, power and the led strip to connect. Please have a look at the S7ripClock for detailed pictures and schematics. Wire colors are the same as can be seen in the pictures.

The sketch is also based on the S7ripClock, so it's offering exactly the same features. According to your choice of power supply you might want to raise the default power limitation of 500mA on top of the sketch.

By changing "enableDot" to "true" you can enable a blinking dot in the center of the grid, if you'd like to.

Basic usage instructions:

Button A: Select brightness

Button A (long press): Switch color mode (per digit/per led)

Button B: Select color palette

Button B (long press): Switch 12h / 24h mode

Button A + B: Enter setup

While in Setup: ButtonB -> Increase +1, ButtonA -> Accept/Next

replaced by v7

LED Strip Speed Challenge

First Prize in the
LED Strip Speed Challenge