Controller selection
Count channels first, then pick the controller. DMX512 gives 512 channels per universe, which is 170 RGB nodes per universe — a 1,000-node facade needs six universes before you have addressed a single pixel. Art-Net or sACN carries many universes over Ethernet and is the normal choice above a few hundred nodes.
For smaller or mobile work, a dedicated pixel controller driving SPI strings directly is cheaper and simpler than a full DMX chain. Our stair light controller and Wi-Fi DMX controller cover the small-install end, with DMX pixel tube and bar systems for larger runs.
Mechanical, IP and UV
Permanent outdoor installations need IP67 minimum, and IP68 if the node sits in a drainage path or is regularly washed down. UV is the second killer: housings that survive two summers in Guangdong may chalk and crack in Arizona. Specify UV-stabilised PC or silicone, and check the mounting hardware is stainless rather than zinc-plated — galvanised clips rust through in a coastal installation within a year.
Commissioning checklist
- Address every node before mounting at height — never after
- Run a red/green/blue/white full-on test before any content playback
- Verify no node string is reversed or mis-addressed at the far end
- Measure voltage at the last node of each injection group, loaded
- Test the full show for 30 minutes and check PSU temperature
- Photograph and label every injection point and PSU for future maintenance
Field failures worth knowing about
Three failures account for most callbacks on these projects. The first is a 12 V installation where the last twenty nodes are pink instead of white — voltage drop, not a bad batch. The second is random flicker that starts after a rainstorm — water in an unsealed connector, shorting the data line. The third is a facade that works perfectly until the show runs at full white — the PSU was sized at the RGB nominal rather than at full-white current draw, which is roughly triple.
We supply pixel point lights, pixel bars, WS2812B rings and mounting accessories in 12 V and 24 V, with WS2811, UCS1903 and DMX512 options. Send us the facade drawing and the viewing distance, and we will return a pitch, node count and injection plan.
Point light installations are deceptively simple to draw and surprisingly easy to get wrong. A facade lighting scheme, a pixel-mapped tree or a concert backdrop is built from hundreds or thousands of individually addressable nodes, and the difference between a working install and a flickering one usually comes down to four numbers: pixel pitch, node power, injection spacing and controller channels. This guide covers them in the order a project actually fails.
What counts as a point light
A point light — pixel node, pixel dot, point source — is a single LED package in its own waterproof housing, addressed individually so the controller can set its colour independently of its neighbours. Diameters from 20 mm to 50 mm cover most architectural and event work, with colour options from single-colour and RGB through RGBW and UCS-style variants.
What separates product families is not the housing but the driver IC inside it. See our 20–50 mm pixel point light range and the 120 mm DMX RGB pixel dot for larger architectural spacing.
The IC decides everything
Two nodes that look identical will not talk to the same controller. The IC determines the protocol, the channel count, the maximum nodes per string and the refresh rate.
| IC / protocol | Channels per node | Typical use | Compatibility note |
|---|---|---|---|
| WS2811 | 3 (RGB) | General pixel work | SPI, not DMX |
| WS2812B | 3 (RGB) | Compact nodes and rings | Stricter timing, shorter data runs |
| UCS1903 | 3 (RGB) | Long event strings | Different timing, own controllers |
| DMX512 | 3 or 4 | Architectural, permanent installs | Standards-based, works with any DMX console |
The single most expensive mistake in this category is mixing IC families across one installation because two batches arrived with different chips. If the scheme is DMX512, specify DMX512 on every purchase order and verify it on receipt — a WS2811 node with a DMX-style connector will power up and then refuse to address.
Pixel pitch and viewing distance
Pitch is the centre-to-centre spacing. It determines both how the installation reads at distance and how many nodes — and therefore how much power and control — you need.
| Pitch | Nodes per m² | Reads as a continuous image at | Typical application |
|---|---|---|---|
| 100 mm | 100 | 15–25 m | Building facades, large media surfaces |
| 150 mm | 45 | 25–40 m | Bridge and tower outlines |
| 200 mm | 25 | 35–60 m | Distant facade, landscape |
| 300 mm | 11 | 60 m+ | Skyline, long-span structures |
The working rule for video content is that the viewing distance in metres should be at least 150–200 times the pitch in metres. If the audience will be closer than that, either reduce the pitch or accept that the content must be abstract patterns rather than video.
Power budget and injection
Each node draws a fixed current at full white — commonly 20–60 mA at 12 V, roughly 0.25–0.75 W. Multiply by node count and add 20 % headroom, and you have your PSU size. Then check the injection plan separately: voltage drop along a long string is what actually kills these installs, not PSU capacity.
Practical limits with 0.75 mm² feed cable: roughly 100–150 nodes per injection point at 12 V, and 200–250 at 24 V. On a 1,000-node facade that means seven to ten injection points at 12 V and four to five at 24 V — the reason 24 V is the default for permanent architectural work. Power the injection points in parallel from a common bus rather than daisy-chaining PSUs, and make sure every PSU shares a common ground with the controller.
Data wiring rules that are not negotiable
- One direction only — data flows in one end and out the other; reversing a string produces nothing
- Keep data runs short — under 2–3 m between controller and first node for SPI, longer only with a differential driver
- Do not run data alongside mains — parallel runs induce the flicker that everyone blames on the PSU
- Common ground everywhere — PSU, controller and node string must share ground or the data reference floats
- Terminate and seal — every unused connector is an aerial and a water path
For shapes that need a physical core — spheres, letters, custom outlines — a screw-ball mount lets you build the geometry first and clip nodes to it, rather than drilling a fixed plate.
Controller selection
Count channels first, then pick the controller. DMX512 gives 512 channels per universe, which is 170 RGB nodes per universe — a 1,000-node facade needs six universes before you have addressed a single pixel. Art-Net or sACN carries many universes over Ethernet and is the normal choice above a few hundred nodes.
For smaller or mobile work, a dedicated pixel controller driving SPI strings directly is cheaper and simpler than a full DMX chain. Our stair light controller and Wi-Fi DMX controller cover the small-install end, with DMX pixel tube and bar systems for larger runs.
Mechanical, IP and UV
Permanent outdoor installations need IP67 minimum, and IP68 if the node sits in a drainage path or is regularly washed down. UV is the second killer: housings that survive two summers in Guangdong may chalk and crack in Arizona. Specify UV-stabilised PC or silicone, and check the mounting hardware is stainless rather than zinc-plated — galvanised clips rust through in a coastal installation within a year.
Commissioning checklist
- Address every node before mounting at height — never after
- Run a red/green/blue/white full-on test before any content playback
- Verify no node string is reversed or mis-addressed at the far end
- Measure voltage at the last node of each injection group, loaded
- Test the full show for 30 minutes and check PSU temperature
- Photograph and label every injection point and PSU for future maintenance
Field failures worth knowing about
Three failures account for most callbacks on these projects. The first is a 12 V installation where the last twenty nodes are pink instead of white — voltage drop, not a bad batch. The second is random flicker that starts after a rainstorm — water in an unsealed connector, shorting the data line. The third is a facade that works perfectly until the show runs at full white — the PSU was sized at the RGB nominal rather than at full-white current draw, which is roughly triple.
We supply pixel point lights, pixel bars, WS2812B rings and mounting accessories in 12 V and 24 V, with WS2811, UCS1903 and DMX512 options. Send us the facade drawing and the viewing distance, and we will return a pitch, node count and injection plan.