Pick-by-Light: Efficient systems for warehousing and order picking
Pick-by-Light increases the efficiency and quality of your order picking.
All professionals are aware of the advantages of paperless picking. It saves time and money while increasing quality and performance. It doesn't matter whether your company is small or large. In modern warehouse logistics, efficient picking plays a crucial role in ensuring smooth operations. With advanced processes such as
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What is Pick-by-light?
Pick by Light refers to a process for picking in warehouse logistics. For this purpose, a pick-by-light system with electronic compartment displays that show the order picker the quantities to be removed directly at the storage compartment. Quick confirmation of removals with the acknowledgment button guarantees very high efficiency. The
The mounting rails can be flexibly configured as a bus or star network with the network-compatible controllers via
Modern wireless technology and ePaper completely replace cabling. The batteries power the compartment displays for several years. An excellent and very flexible solution for small systems.
Each order picking trolley can be equipped Multi-Order-Picking pick-by-light displays for Multi-Order-Picking . The order picker is guided optimally through the warehouse and distributes the items to the target compartments quickly and reliably.
In this comprehensive guide, we help you find the best solution for your modern and efficient picking process. Here we have compiled the most important types of pick-by-light systems, as well as the advantages and disadvantages of picking without a pick list. With this comprehensive information, we help you make your purchasing decision for
Procedure with step-by-step explanation
Thanks to pick-by-light, pickers don't need to waste time constantly checking their picking lists. The illuminated compartment displays show them the most important information directly at the storage compartment. A rough overview of the process can be summarized as follows:
- Picking, assembly, or sorting is activated.
- The pick-by-light compartment displays light up and indicate the quantities to be picked.
- The order picker performs his tasks and confirms them directly using the confirmation button on the storage compartment.
- Stock changes are posted immediately in inventory management.
Wired
Pick-by-Light
We offer over 120 variants of high-quality, wired pick-by-light compartment displays with various options. All compartment displays are equipped with a double, 7-color LED. The selection of the appropriate compartment displays and their features depends heavily on the requirements.
The classic in warehouse picking in 2026.
The 3-digit quantity display shows withdrawal quantities with a maximum of 999 pieces.
| Type | PTF-3N-4 |
| height | 50 mm |
| width | 130 mm |
| depth | 25 mm |
| display | Red 3-digit, 7-segment display with high brightness, dimmable |
| LED | Two horizontally divided, 7-color high-intensity signal lights |
| keys | Robust acknowledgment button, plus, minus, and F button |
| sensor | Optional: as automatic access recording. Find out more here: Pick-by-Light sensor |
| Areas of application | Storage compartment display for paperless picking, assembly stations, sorting, sequencing, set formation, shelves and pallets, Multi-Order-Picking |
| Power | Up to 350 picks per hour |
| system | Suitable for order picking, assembly, and production. Controlled via LUCA software. |
| expenses | Upon request |
Hardware: Setup, installation, options
The Pick by Light hardware guides the picker with light and consists of:
- Controller (communication and power supply)
- Mounting rails with integrated BUS (marked yellow in the diagram)
- Specialized displays with signal lamps (2 x 7 colors), quantity display, and an acknowledgment button
- Wiring with 4-wire cable between the mounting rails and controller
Installation, assembly, and commissioning are very straightforward. The system is optimally prepared and designed for this purpose. Configuration is carried out directly on the displays. Conversions and expansions are child's play and can be carried out by trained personnel themselves.
The system is one of the best in order picking, is modular, and has a very flexible design. Installing and mounting the displays at each picking location is easy, and subsequent modifications are straightforward. This is where KBS comes in. Shelves or mobile structures are ideal for this purpose. Regular maintenance is recommended and ensures the long-term quality of order picking.
The functions are clearly structured and the light signals are unambiguous. The system supports various barcode scanners, RFID readers, and scales.
Additional options:
- Sensor for automatic acknowledgment monitors access to the storage compartment (access monitoring).
- Digital I/O for receiving and transmitting external signals.
- beep
The system is controlled in real time by LUCA software. The connection to the higher-level system, material flow, and conveyor technology is established via the LUCA-Server, which controls all processes.
Error prevention with the innovative sensor directly on the pick-by-light compartment display
The pick-by-light sensor has an important new function in the removal confirmation process. It can be installed above or below the display as an option. The sensor monitors access and also automatically confirms the activities. The installation of the sensors must be precisely coordinated. As a light sensor, it can measure 15-20 cm without a reflection mirror. With a reflection mirror, even 80-100 cm is possible.
Learn more about the pick-by-light sensor.
Wireless pick-by-light system
A wireless pick-by-light system is a solution in which each pick-by-light compartment display is equipped with a battery, radio transmitter, and radio receiver. In the area of application (e.g., a warehouse), bidirectional antennas are additionally wired and installed for data communication with the wireless compartment displays.
This solution is very interesting for mobile installations where a high degree of flexibility is required. Although the response times are much slower than with a classic pick-by-light system, they are sufficient for some processes. The battery replacement justifies the simple solution.
Setting up the infrastructure with permanently installed antennas is also manageable for small areas.
Our conclusion on wireless pick-by-light
Das drahtlose Pick-by-Light System mit Vernetzungstechnologie ist für einfache, kleine (<100 Displays) und langsame Ablaufprozesse in der Kommissionierung von Sets und Montage sehr gut geeignet. Die Bauteile und Werkzeuge können damit schnell signalisiert werden.
Updating the content on the ePaper display takes approx. 20 seconds. The LED lights up within 2-3 seconds. For this reason, the wireless displays are very well suited for certain purposes (static display content), but do not replace the classic, wired pick-by-light solution.
For large installations (e.g., on shelves), classic, hardwired solutions without radio are more suitable (see wired pick-by-light).
Mobile devices put-to-light
Mobile use of the pick-by-light display units is of course possible on the picking trolley or on a mobile frame construction. In this case, a replaceable and long-life lithium-ion battery powers the hardware components. The WiFi module provides mobile data connection to the control system. Such solutions are known as Put to Light .
Connection of the pick-by-light system
The flexible connection of the system to a higher-level system is crucial for optimal process flow. This can be a warehouse management system or ERP program. The advantages of a simple and fast interface are essential and have a major impact on many functions throughout the entire process.
standard interface
The standard interface is implemented via TCP/IP socket. Two asynchronous TCP/IP channels are established for data transmission in both directions.
Communication channels to Pick by Light
The first channel (download) is used to activate and deactivate the displays. The telegrams contain many parameters. The second connection channel (upload) is responsible for feedback on acknowledgments, corrections, special messages, and error messages.
A reception acknowledgment is sent to each channel. This ensures that data is transferred quickly and securely. For more details, see the article: Standard interface.
Customized connection
In some cases, the process and data supply need to be optimized. We develop customer-specific connections for this purpose. Contact us to learn more.
Software and commissioning
The pick-by-light software forms a link between the hardware and the higher-level warehouse management system. It is installed on a Windows server provided by the customer and regularly checks the availability of the compartment displays. This software also controls the entire picking process.
One of the most important aspects of good software is the response time and processing speed at the interfaces. The professional LUCA server is used as the basis for control here. LUCA-Server , which is very fast and supports different picking procedures. The development is modular and highly flexible. The process can be adapted very flexibly to customer requirements.
The core of the software uses exclusively object-oriented ANSI C++ as its programming language. This guarantees high performance, stability, and reliability.
The main features of the software include:
- Communication with the hardware and the warehouse management system
- System configuration (e.g., assignment of compartment display labels in a warehouse layout)
- Monitoring and status messages in case of malfunctions
Operation is very intuitive and easy to understand. Thanks to the special configuration lists, even very large systems can be quickly put into operation.
Services provided by the customer
In order to integrate a pick-by-light system smoothly, certain prerequisites and on-site services must be met:
- A higher-level warehouse management system or production control system should be in place (except for stand-alone systems).
- The latest version of Windows Server (e.g., as a virtual machine).
- A database (Oracle, MS-SQL, or MariaDB) is only necessary for complex order management.
- Shelves with ergonomically prepared mounting surfaces.
- Ceiling suspensions as required (e.g., for free-standing pallet spaces without shelves).
- Cable trays for large shelf spacing.
- Power supply for the controllers 230V (16A) or battery chargers.
- LAN network or WiFi for mobile systems.
Areas of application and the most important differences
The following industries have been using our system for many years to support their picking tasks:
- eCommerce:picking warehouse, replenishment, sorting station in the shipping warehouse
- Automotive:Batch processing and sequencing of shopping carts and JIT racks for assembly lines
- Production:Assembly stations, set construction, and machine loading
The pick-by-light system is a highly versatile picking method that supports pickers and prevents picking errors. It has a wide range of applications. For more details, see the article: Where is pick-by-light used?
Differences between the individual types of specialist advertisements
The displays are equipped differently depending on the area of application. Each display is equipped with at least one LED signal light and one button. The other features depend heavily on the different requirements.
In standard picking for e-commerce, the display of the withdrawal quantity is mandatory. In a sequencing process in the automotive industry, the withdrawal quantity is constant (almost always equal to 1), so the quantity display can be omitted. On the other hand, additional information often has to be displayed in production. Special display types are used for this purpose.
If you are unsure which types of ads are best for you, we will be happy to advise you.
The complete list of all display types can be found here: Pick-by-Light hardware.
When does it really make sense to use a pick-by-light system?
The system is not very cheap. For this reason, its use must be planned correctly and sensibly. The system is best suited for:
- Fast order picking with high quality standards.
- Small and lightweight items that can be moved manually.
- Fast-moving items (frequent relocations or new items).
- Items that are difficult to distinguish (e.g., during assembly and set formation).
- Changing personnel who need to be trained quickly.
We are happy to assist you with your plant planning. Please contact us.
Pick by Light in order picking
Paperless picking process based on a pick list with picking orders. The warehouse management system transmits the data and distributes it to the appropriate picking areas in the picking system. There are many variations in how this works.
The standard process
LUCA offers standard software that already meets 80% of all requirements for picking from a storage location. The aim is to minimize the error rate and speed up the picking process. However, the requirements for the system are often very specific.
Start of processing in Pick by Light
There are basically two different start methods here:
- Start via a document with barcode
- Start of paperless picking via FIFO or external triggers
If the delivery notes, boxes, or containers are marked with a barcode, barcode scanners can be used directly. In this case, the displays can also be activated via the delivery note or invoice. RFID technology is also supported.
Confirmation of removal using the acknowledgment button on the compartment display and end of order
Once all items have been picked from the storage location, the picker confirms the removal directly at the compartment using the confirmation button on the compartment display. This confirms the removal.
If the quantity is incorrect, the correction keys (+/-) can be used to make corrections to the quantity. Confirmation of the withdrawal triggers a feedback message to the higher-level warehouse management system (WMS).
Support in assembly and production
Assembly work often consists of many steps. Employees must correctly reach into many containers according to the assembly instructions. An assembly process with instructions on a piece of paper is not ideal. Illuminated displays can significantly increase performance and quality.
You can find out more in the article: Pick-by-Light Assembly
Suppliers and manufacturers
As a manufacturer, supplier, and expert in picking solutions with Pick by Light, LUCA Logistic Solutions is highly flexible thanks to the software of the LUCA communication server. We offer various technologies to achieve the optimal solution for the customer. We have been building our picking systems since 1998.
How effective is Pick by Light, and how much does the system cost at LUCA?
Performance and quality are opposing parameters. As a result, the more performance is expected, the less quality the picker can deliver and the higher the error rates become. Increasing performance and quality at the same time is not easy with any of the picking methods.
The goal is to be faster and cheaper. The capabilities of the control software are crucial here. Simple conversion options are also important.
As a leading picking method, Pick by Light provides us with an excellent example of how performance and quality can be rapidly improved. Operator guidance is enhanced by light signals.
The rare repairs or replacements of the display panels confirm the stability of the system. Any troubleshooting usually does not require the intervention of LUCA specialists.
Performance in order picking
Performance increases by up to40%. Targeted support for access to storage compartments also increases quality by more than15%. This minimizes picking errors and training time.
When sensors are used, the quality increases by a further10% or so.
The ROI calculation and the costs
When planning the system, it is essential to consider cost-effectiveness and efficiency gains. The low cost of the hardware means that the equipment is relatively inexpensive to purchase. The costs for the projects are justified by the expense of the hardware. You should budget for hardware costs of €60 to €100 per storage compartment (depending on the type of hardware used).
An ROI calculation must show whether the investment is profitable for the company.
The big comparison between pick-by-light and put-to-light?
In this table, we have compiled the most important differences between the systems for you.
If you have never heard of the term " put-to-light," read this first: What is put-to-light?
| properties | Pick by Light | Put to Light |
|---|---|---|
| Areas of application | Picking individual orders, assembly, and production | Replenishment of goods, Multi-Order-Picking, distribution and sorting of goods, set formation |
| activation | Reading the order number (barcode, QR code, or RFID) or automatically in conjunction with conveyor technology | Reading the item number in conjunction with a Multi-Order-Picking |
| FIFO usage | Yes, it is possible. | No |
| Direction of activity | The items are removed from the storage compartments and placed in containers or boxes. | The items are removed from containers or pallets and placed in the designated storage compartments. |
| Type of acknowledgment | Acknowledgment button or sensor | Acknowledgment button, sensor, or mobile scanner |
| Time of response | After the end of the withdrawal | Immediately after filing |
| Special features in the structure | none | none |
| Most suitable display types | PTF-3N-4, PTF-OL-1, PTF-S3N-3, | PTF-L-6, PTF-L-7, PTF-SL-3, |
| Customized design | Yes | Yes |
Pick by Light: Advantages and disadvantages
We have compiled all the advantages and disadvantages of pick-by-light for you:
| Advantages of Pick by Light: | Disadvantages of pick-by-light: |
|---|---|
| Short search time for items | Relatively high acquisition costs (KBS) |
| Hands-free picking | Not suitable for free-standing pallets |
| High freedom of movement and quality | Only partially multi-user capable |
| Language-independent | |
| Increases efficiency and productivity | |
| Reduces picking errors | |
| High performance of the order picker and short throughput times | |
| Quick quantity correction with direct feedback of stock changes to the warehouse management system |
Our conclusion
In logistics and production, Pick by Light is one of the best and most widely used error-free picking systems. The picker intuitively follows the light signals and quantity displays at the picking location, thereby minimizing search time (operator guidance through the orders). Numeric and alphanumeric quantity displays show the number of items. Correction keys help in the event of inventory errors.
The simple installation of KBS, robust acknowledgment buttons, and flexible conversion options make this solution very attractive. Easy connection to any warehouse management system brings enormous advantages. The system can also provide excellent support for permanent inventory. The goal is optimal user guidance through customer orders.
However, in large warehouses with many storage compartments, the cost of installing the displays is quite high.
Put-to-Light can also be used on vehicles with Wi-Fi to optimize picking times, travel times, etc. during order picking.
You can find out more about Put-to-Light here: What is Put-to-Light?
The system is Industry 4.0-compatible and is a leader in paperless order picking.
You can find out more about the history in the article: "History and Development."
Synonyms for Pick by Light are: Pick-by-Light, Picktolight, Pickbylight, Pick-2-Light, P2L
Further definition on Wikipedia.
Leading expert and consultant in the field of pick-by-light, picking systems, and classic material flow control systems. An innovative software developer and inventor of various systems.
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His motto: "The focus is always on a good idea, not just the technology."
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Frequently Asked Questions
Pick by Light (or Pick to Light) refers to a process in warehouse logistics for picking orders with the aid of light signals. The system with electronic compartment displays shows the picker the quantities to be removed directly at the storage compartment.
The costs depend on the number of compartment indicators, the length of the shelves, and the software functions. You should budget €100 per storage compartment.
Further information on pick-by-light.
As soon as a picking order is activated, the compartment indicators light up, signaling the picking compartment and the picking quantity from a distance. The picker confirms the goods removal (pick) at a confirmation button.
For a pick-by-light system, you first need the compartment displays, which are mounted at each storage location. They include LED lights, quantity displays, and several buttons. As a further system component, you need the controllers, which are used to supply the devices with power and data. Finally, you will also need mounting rails, terminals, and cables. KBS hardware offers the best flexibility. If you would like to find out more, visit: Pick-by-Light in 2024 – LUCA Logistic Solutions.
The SAP interface is not implemented directly with the hardware, but via a server. The server communicates with the specialist displays on the one hand and with the higher-level system, e.g., SAP or warehouse management, on the other.
The connection via a server can be flexibly designed with RFC, TCP/IP, databases, etc. Read more about this at: Pick by Light Picking – LUCA Logistic Solutions
1. Number and types of indicator lights (see: Pick by Light Hardware – LUCA Logistic Solutions)
2. Number of mounting rails for attaching the modules
3. Total length of the mounting rails
4. Layout and functional description
5. Inputs for the host or warehouse management system
