Overview
I evaluated Lingguan Technology's LED control card model LGSVSTR04 for use with a P10 display module. The card is a 5 V device and supports both Ethernet and serial communication. I tested the Ethernet interface and the RS232 serial interface.
Key findings from testing
- The P10 display module requires a high supply current, up to 5 V 5 A. Using a 5 V 1 A power supply caused frequent disconnections between the PC and the LED control card because the power supply could not drive the P10 module.
- Actual use rarely requires maximum brightness. Reducing brightness lowers the required current and can prevent power-related instability.
- The P10 module is a bicolor module with dense red and green LEDs, so it can display red, green, and yellow text.
- The P10 module pixel matrix is 32×16. Mismatches in expected pixel dimensions were the reason for many initial display issues.
Common LED module sizes and pixel counts
| Module name | Module size | Display pixels |
|---|---|---|
| P3.75 | 30.4 cm × 15.2 cm | 64 × 32 |
| P5.0 | 48.8 cm × 24.4 cm | 64 × 32 |
| P6 | Two options: 19.2 cm × 9.6 cm (32 × 16) or 38.4 cm × 19.2 cm (64 × 32) | See module size |
| P7.62 | 48.8 cm × 24.4 cm: 64 × 32 (can be cut to other sizes for specific applications, e.g. taxi in-vehicle screens: 48.8 cm × 11.2 cm / 64 × 16) | See module size |
| P10 | 32 cm × 16 cm | 32 × 16 |
Common LED module single-board dimensions and display pixels
Pixel calculations and module matching
How are display pixels calculated, and how is a display matched to a control card?
Pixel calculation for LED module specifications
- Pitch calculation: Pixel pitch is the distance between two pixel centers. Each pixel can be one LED (for example PH101R), two LEDs (for example PH162R), or three LEDs (for example PH162R1G).
- Length and height calculation: pixel pitch × number of pixels = length or height.
Examples:
PH16 length = 16 pixels × 1.6 cm = 25.6 cm; height = 8 pixels × 1.6 cm = 12.8 cm.
PH10 length = 32 pixels × 1.0 cm = 32 cm; height = 16 pixels × 1.0 cm = 16 cm.
3. Number of modules required for a screen: total area ÷ module length ÷ module height = number of modules.
Example: For a 10 m2 PH16 outdoor single-color LED screen:
10 m2 ÷ 0.256 m ÷ 0.128 m = 305.17678 ≈ 305 modules.
More accurate method: modules in length × modules in height = total modules.
Example: For a PH16 single-color screen 5 m wide and 2 m high:
Modules in length = 5 m ÷ 0.256 m = 19.53125 ≈ 20 modules.
Modules in height = 2 m ÷ 0.128 m = 15.625 ≈ 16 modules.
Total modules = 20 × 16 = 320 modules.
Practical example
Assume a fully outdoor P10 display with width 4.0 m and height 0.5 m. Calculate the required number of modules and the display pixel area to determine an appropriate GPRS wireless control card.
One P10 module size: 32 cm × 16 cm, pixel count 32 × 16.
- 400 cm ÷ 32 cm = 12.5, so use 12 modules along the width.
- 50 cm ÷ 16 cm = 3.125, so use 3 modules along the height.
- Total modules required = 12 × 3 = 36 modules.
- Display pixels = 12 × 32 = 384 pixels by 3 × 16 = 48 pixels, so total 384 × 48 pixels.
Given this pixel count, a control card such as the LGSV7020B GPRS model can be used to drive the display.
