StereoLM.RU - Stereo Level Meters
Embed lowcost-module of audio stereo-signal level indocator with automatic gain/scaling adjustment StereoLM-EC ver 1.0

Embed lowcost-module of audio stereo-signal level indocator with automatic gain/scaling adjustment StereoLM-EC ver 1.0

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The module is designed for embedding into the equipment and to display the dynamics of changes in the amplitude of the audio frequency signal using a linear LED scale. The device allows you to evaluate the dynamism of musical audio recordings due to the built-in automatic signal level adjustment system (AGC). For this reason, the device is not designed to measure absolute voltage values.

The AGC system allows you to scale the signal evenly over the full length of the scale, regardless of the actual amplitude of the signal which allows you to use the indicator in circuits after volume/tone control devices without the need for manual adjustment of the indicator when used with various sound reproducing equipment. Even with the minimum value of the set volume, the indicator will scale a small signal amplitude to the full scale. When the indicator is disconnected from one signal source and connected to another source, automatic adjustment will occur and no additional user actions will be required.

To assess the difference in peak voltage values of both channels, an indication of maximum points is provided. With musical bursts, these points are "thrown up" by the main column of LEDs, and slowly "decrease" with sharp drops, which allows you to see short bursts.
Price List
Batch (pcs)
Price for 1 pc
≥ 104.07$
≥ 203.98$
≥ 303.95$
≥ 403.94$
≥ 503.79$
≥ 1003.56$
10 pcs  ✔  in stock
Key Features
  • The compact size of the module allow you to embed it in any audio equipment.
  • Audio signals and power supply voltage are supplied via wires that are soldered to the module pads by yourself.
  • The module's printed circuit board is designed in such a way as to be able to directly solder LED tapes to the edges of the module. At the same time, two soldering options are provided for each channel: two parallel tapes - soldering on same side (edge) of the board; two tapes in different directions under one axis - soldering at two opposite edges of the board.
  • The device works with a large number of addressable WS2812B LEDs (128 max. that twice as many as other devices of the same type).
  • When order you can pre-adjust number of LEDs, the color of each LED and/or smooth color transitions (gradients), as well as brightness in accordance with the power of your 5 Volt power supply.
  • After purchase, you can change the noise reduction level yourself if necessary.
Block Diagram
StereoLM-EC - Block Diagram
Type of module
Embed lowcost version
A printed circuit board with components. The enclosure is not provided. LED tapes can be provided for a additional fee and are not included in the base package.
Lots of LEDs supported128
Two tapes of 64 LEDs each. The minimum number of LEDs is 6. The number of LEDs can be reduced within the specified limits.
Supported LED typesWS2812B
The need to use capacitors in parallel to each LEDYes
Indication of the inert maximum point thrown up by the main columnYes
The color of the maximum point is always equal to the color of the last (upper) LED in the tape.
Connectors for external wiresNo
Only soldering of wires to the provided contact pads.
Size (Length x Width x Height), mm27.0 x 12.0 x 5.0
Including components on the board.
The distance between the longitudinal centers of two parallel LED tapes15.0 mm
Multidirectional physical connection of LED tapes optionYes
Parallel in one direction or in opposite directions along the same line.
Supply voltagefrom 3.0 to 5.3 В
Incorrect power supply polarity protectionNo
Current consumption<10.0 mA
Without current consumed by the LEDs.
Additional power saving mode after 10 seconds of silenceNo
Color selection for each LED24 bit
> 16M colors
Independent color selection for stereo channel LED tapesYes
Colors gradientYes
The number of gradient points is unlimited (equal to the number of LEDs).
Proportional limitation of the brightness of the LED tapes depending on the load current capacity of the power supplyYes
When ordering you can specify the current that the power supply is capable of providing. For example, a computer port (USB 2.0) can provide a current of 500 mA. Most cheap chargers also provide a current of 500-600 mA. Standard stabilizers 7805 provide a current of 1000 ... 1500 mA (if there is a heat sink). ATTENTION! When 128 LEDs are On at maximum white brightness the instantaneous/pulse current consumption of the LED tapes can reach 4800 mA. When setting the colors the brightness of the LEDs will be set automatically according to the maximum current value specified when ordering. If the current is not specified when ordering the maximum brightness will be set by default.
Mono mode (indication of the level of only the left or only the right channel on a single LED tape)No
You can simply not connect one of the LED tapes.
Automatic detection of the connection of LED tapesNo
The possibility of displaying the indication of two channels on a single LED tapeNo
It is possible to solder the LED tapes both in parallel and in different directions, which is visually equivalent to output to a single line.
Disabling the indication of the inert maximum point optionNo
Adjusting the overall brightness of the LEDs option (from 0 to 100%)No
The brightness is calculated automatically when specifying the current that an external power supply is capable of providing.
Reversing the indication of channels separately optionNo
Indication from top to bottom (left to right) or bottom to top (right to left).
Noise reduction level selectionfrom 2 to 13 mV
The noise reduction level is set to 2.15 mV by default. The level can be changed by short-circuiting the outputs (lines) of scales on PCB to a positive power line (before power supply): left output - 4.3 mV level, right output - 8.6 mV level, both outputs - 12.9 mV level. After change it is impossible to return to the value of the 2.15 mV level.
Self-configuration of module parametersNoise reduction level only
Software application: Stereo Level Meter EC 1.0 (StereoLM-EC.exe)
Software application: Stereo Level Meter EC 1.0 (StereoLM-EC.exe)
  • Application is intended only for making of the module firmware file. With its help you can configure the module before it will be sent to your postal address, so self-configuration after purchase is impossible. You can only change the noise reduction level yourself.
  • It is possible to specify qty of LEDs and the colors of any number of gradient points, between which there will be a smooth change in the color of the LEDs.
  • The application allows to set the maximum current of the power supply and automatically calculate the total brightness of the LED tapes corresponding to the power of the power supply.
Compare table for group: Stereo signal level indicators based on LED tapes [0.25 MB]
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