Protopixel deploy best practices

ProtoPixel installation best practices

1. Summary

Please read this documentation before installing any type of ProtoPixel’s lighting control tools. This guide will provide the steps to follow and is crucial to avoid potential damage produced by its wrong manipulation. 

During the installation, you will need certain consumables to make connections between controllers and LEDs. 

Some additional specific tools are needed to properly install the lighting fixtures, like a given size screwdriver among others. Please check that you have all the tools needed as described in section 5.

Finally, we give you some advice regarding the praxis to follow to make everything more professional and avoid long term problems. We encourage you to follow these recommendations to achieve the best result, aesthetically and technically.

2. Tools and materials recommended

We recommend you to dispose of some specific tools in order to comply with the Praxis and recommendations as detailed in the next section. The most common materials that you will need are:

• Tin welder (only if you are going to cut and put new wires on LED strips)
• 26 - 40 W maximum (not more than 350ºC)
• We recommend straight conical tip
• Scissors (only if you are going to cut a LED strip)
• Wire stripper
• Crimping tool for wire end-caps and power supply tips
• A 3 mm flat screwdriver, will be used for all ProtoPixel controller families
• Fast connectors, we recommend Wago 221 - 413 or similar

3. Installation

To achieve an outstanding result in your installation, we detail the praxis to follow and some recommendations.

3.1. Cable section

DC wires

DC wires are the ones that bring power to the fixture (and controller in some cases), they connect the power supply to the LED fixture. We recommend keeping DC wires as short as possible, as long as the eventual physical constraints allow for it (design constraints, size of power supplies, maintenance, …).

Follow the recommended section for wiring the DC output from the PSU to LEDs. The wire section will be determined by the voltage, distance from PSU to luminaries, and power consumption. Using a small section can cause overheating of the cable, voltage drop, and in some cases risk of fire.

Digital LED strips usually work at 5, 12 or 24 V depending on the model (LED grouping and IC). Voltage drop should be calculated in the project design phase to properly select the wire section.  As an example, in the following table, it is shown three different LED fixtures that consume 150 W and work at 5, 12, and 24 V each with different cable lengths. For each case, a wire section is calculated. Note that red and orange highlighted wire sections are too big for being directly soldered to the LED strip.

Distance (m)	Voltage (V)	Power (A)	Wire section	Voltage drop
10	5	30	13.3 mm2 (6 AWG)	1 V
10	12	12.5	5.26 mm2 (10AWG)	1 V
10	24	6.25	3.31 mm2 (12AWG)	0.8 V
5	5	30	8.37 mm2 (8 AWG)	0.8 V
5	12	12.5	3.3 mm2 (12AWG)	0.8 V
5	24	6.25	1.31 mm2 (16AWG)	1 V
1	5	30	1.31 mm2 (16 AWG)	1 V
1	12	12.5	0.83 mm2 (18 AWG)	0.7 V
1	24	6.25	0.83 mm2 (18 AWG)	0.7 V

This table is for a hypothetical fixture that consumes 150 W

We do not recommend a voltage drop higher than 3%. Keep in mind that there is also a voltage drop inside the LED strip which will be determined by its physical characteristics like tape length, material (copper VS aluminum), track width, etc.

Data bus wires

We refer to data wires when we speak about the data and ground wires that go from the LED strip to the controller/receiver. In further sections, we will focus on specific controller wires.

In general, we recommend a pair of wires of 17 - 18 AWG (1mm2). These cables should go directly from the controller/receiver to the digital LED strip. It is very important that these cables run in parallel and have exactly the same length.

The maximum length of data wires depends on the digital LED IC. As digital LED strip wiring protocol is meant to be used in the same PCB with very short distances, we recommend using the shortest data cable possible, ideally less than 50 cm. If it could not be possible to keep this length, we do not recommend distances larger than 1.5 m at the maximum extent. Otherwise, LEDs could start flickering at any moment and its behaviour could be erratic.  

3.2. Crimping cables

A crimping tool allows you to join and protect the end of the cable, preventing small filaments to cause short circuits. This is especially critical when connecting data and power wires to the controller. If a filament of the V+ touches the data wire, the outlet could be permanently damaged, and would not be covered by the product warranty.

Use proper end caps for the connection ending and wire section. A loose cable is potentially dangerous to destroy your LED installation. 

3.3. Connections

Never use insulation tape, a loose wire can cause heat, make a short circuit with other wires and permanently destroy the controller. A great option to consider is the use of Wago terminals, they accept cables from 24 to 12 AWG with 11 mm length of peeled wire. Avoid splicing data wires, each union is an entry point of signal noise.

If you want to splice DC wires, please choose a proper expandable item according to the wire section and power to prevent overheating and loose cables. 

3.4. Powering the LEDs with more than one PSU

More than one PSU can be used to power a LED strip, although we do not recommend doing this practice. As a general rule, it is better to select a power supply that satisfies the requirements of the LED strip. 

Even though we do not recommend it, if you want to use two power supplies for the same fixture, never join positive wires. It can cause feedback and destroy the LED strip and control equipment. 

Ground wires of the luminaires controlled by a given device should be shared.

See the following schematics on what you should and should not do:

To avoid...	Insted

4. Digital LED

4.1 ICs compatible with ProtoPixel

First thing before identifying potential LED strip candidates, you should check that the Integrated Circuit (IC) of the luminaire is compatible with ProtoPixel enablers. The list of ICs supported by ProtoPixel is an evolving list that is available in our Help Centre.

 

4.2 SPI protocol

Digital LED tape uses an SPI serial interface to independently control the color and brightness of each individual LED. By passing control data through SPI protocol, it enables a range of addressable lighting possibilities far beyond traditional LED tape. 

The protocol used from the receiver or Gate SPI Wired to the LED strip is SPI or one wire protocol. This communication protocol is designed for short distances inside the same PCB. Therefore, there is a limitation in terms of the distance from the Gate SPI Wired or Receiver to the first LED.

 

4.3 Cutting digital LED strips

This section provides some hints and useful information about how to cut LED strips or tape according to its characteristics. The LED market strip is huge, so it does not aim at providing an exhaustive list of all possible LED configurations, but rather focus on those that are more popular or common to find. Should you have any specific , we recommend contacting your LED strip provider if you have doubts. 

One Pixel one LED

These are the ones that are commonly found in the market as 5V digital LED strips: ws1812b, sk6812. Now there are more convenient newer versions of this same LED strip at 12 V plus backup data such as ws2813, ws2815, sk6813

Without backup line:

• Can be cut every single LED, so one LED is a controllable pixel by itself.
• We recommend giving up the first and last LED to get bigger copper PADs for soldering.

With backup line:

• Can be cut every LED, so one LED is a controllable pixel by itself.
• We recommend giving up the first and last LED to get bigger copper PADs for soldering.
• Controllers do not have a backup line, so we will only join the data line to the data output of the controller.
• When jumping from a LED strip to another LED strip, you should connect all 4 wires: Ground (G), D (Data), B (Backup), and V (positive).

One Pixel many LEDs

These LED strips group a set of LEDs inside a Pixel. Each pixel can group 3, 6, or even more LEDs.

• As LEDs cannot be separated from a Pixel, these strips can only be cut each 3, 6, or other combinations of LEDs according to its pixel pitch. The LED strip will show with a line on the silk screen where it can be cut. If you are not sure, please ask your LED provider.

12V three LED per pixel example

24V six LEDs per pixel example

LED strips with DC-DC converters

Beside the previous possibilities, there is another LED strip model that is tricky as it combines 5 V LEDs/pixels into a 12 V LED strip. These LED strips use a DC-DC converter to convert 12 V to 5 V.  Be very careful, as they are labeled to be cut by each LED/pixel, they cannot be cut easily.

• To avoid unpowered LEDs, we recommend cutting from the beginning and end of the DC-DC converter group. You will be able to identify this boundary with a different identification of the 5 V, as it is usually cut or does not exist (black pad on the following LED strip) as you can see in the following image.

5. Wiring the ProtoPixel controllers

5.1 Gate SPI Wired

ProtoPixel Gate SPI Wired is designed for being placed right next to the luminaires, we recommend the shortest cable length as possible (maximum 1.5 m). It has two modes of operation (standalone and orchestrated with the Brain Experience) and also can operate in WiFi and Ethernet modes. You can find all documentation related to this product in our Help Centre. 

As per the power, the Gate SPI Wired can be powered using the same Power Supply Unit as the luminaires, with DC 5 V to 24 V. For each of its data outlets, you can control up to 1200 RGB pixels at 27FPS. This is a trade-off between amount of data (control capacity in pixels) and data speed (framerate) that can be adjusted through the Gate SPI Wired WebApp according to the lighting infrastructure and content requirements. 

ProtoPixel Gate SPI Wired can be installed in different ways:

• One LED strip, one power supply
• Two LED strips, one power supply
• Two LED strips, two power supplies.

One LED strip, one power supply

Two LED strips, powered with same PSU

Two LED strips, powered with two PSUs

5.2 ProtoPixel Gate SPI Wired Long-Range

The Gate SPI Wired Long-Range has eight outlets which send out RS485 serial communication protocol. Each outlet connects the controller to a receiver which is located next to the LED luminaires and is the element in charge of converting RS485 signal to SPI. 

The maximum distance between the Gate and the Receiver is 330 m. The Receiver should be located right next to the luminaires, with a distance shorter than 30 cm.

We recommend using a low impedance RS485 wire with a shielding, especially important to isolate the signal in case that you have additional installations in parallel (like audiovisual or AC power). As they are not easy to find in 330 m packages, we recommend using cat6 SFTP or better (cat7) to wire the controller outlets to the receivers. As a reference, an Ethernet Wire has 4 twisted pairs.

In the following schemas, you can see different ways to install the Gate SPI Wired Long-Range outlets. 

One Ethernet wire per receiver

This is the most common wiring schema, as it allows each outlet to control an individual fixture. With this approach, the fixtures do not need to be physically close. 

By using Ethernet wires dedicated to each outlet, you will have three backup lines just in case a twisted pair is damaged during the installation.

One Ethernet wire, multiple receivers

This wiring schema is useful if you have 4 receivers close, such as pixel Matrix walls/ceilings. In this case, four outlets are grouped together into one single wire, reducing the amount of wires. On counterpart, you will get 4 receivers in the same spot.

Wiring the receiver

In the previous subsections, we show how to wire the controller to the receivers, in this section we show how to connect the receiver to the LED strip. As commented on the Data bus wires section, we recommend the shortest cable length as possible.

To avoid using multiple power supplies for the same LED strip, we recommend using a well-balanced power supply for each receiver. The previous schema shows how to wire the controller and the LED strip. Please bear in mind that you may need to power the LED strip from different points. This can be done as long as you never wire the two VCC+ cables from both Power Supply Units.