“This is the additional project for the Sound Level Meter (From hereafter as SLM) circuit making.
I introduced the SLM prototype in the previous instructable as below.
While working on the SLM prototype, I thought several improvements can be applied to make better SLM devices.
Therefore, additional two SLM variants are made by applying the following improvements from the prototype.
- Miniaturing the prototype to reduce the footprint of SLM to locate it anyplace near to the speaker
- For better visual effect, changing LED types (Thick square type or highly bright small LEDs)
- Dividing MIC/pre-amplifier from LM3915 display part to locate electrets MIC conveniently very near to the speaker
I didn’t change any circuit components (MIC, pre-amplifier, LM3915 display part) included in the prototype.
These 2nd versions of SLMs are only changing shape, configuration, and assembling methods from the prototype.
As a result, the new SLM will be more convenient to use and fun to look at their operation along with changing audio sounds.
Let’s look at more details about how these new SLMs are made.”