Tataylino.com - Passion in Electronics

64×64 RGB matrix half screen issue

I recently got to work with 64×64 RGB matrix and got into some issue. For some reason it only displays half of the screen. After some research, I figured it is just a simple problem.

About the Circuit

I am just experimenting with 64×64 LED matrix because I want to get familiar with it for my next big project. I am using ESP32 module for controlling it. And arduino for programming .

About the 64×64 LED matrix module. The module is using HUB75 link, a standard for LED video wall

What is the cause of this problem

So basically we have 5 lines of address, pins A, B, C, D and E. for the schematic I missed the pin E. Without the pin E, it can only address up to 16 lines. There are 2 RGB lines so 16 lines x 2 RGB lines is 32 lines only. That is why it can only display half the 64 lines.

High Voltage AC detector for Arduino

Currently I am working with a automatic transfer switch for solar power and I needed something to detect if there is an AC voltage output of the power inverter and the Distribution utility.

Why use Lifepo4 Batteries for e-bikes?

Lithium iron phosphate (LiFePO4 or LFP) batteries have several advantages over lead acid batteries when it comes to use on electric bicycles, or e-bikes.

Monitor Mixer with DI Box

One of the problem for low budget band online streaming is the mixing part. The biggest challenge is getting the mix right. Why is it hard? Guitar and other instruments have their own amplifier so when you are doing the mix, you would likely decrease the level of these instruments to the main mix. If you are feeding the main mix into your online live feed, chances are these instruments are too silent on the main mix.

This circuit can be use as a headphone amp mixer with built in DI box so you can directly feed the output into the mixer. There are 2 volume knobs, one knob is used for your instrument volume and the other knob can be used as a monitor level feed from the mixer.

TDA7419 Project (Bluetooth + spectrum analyzer + bass mid treble volume control)

Here is a simple circuit that have 7 band spectrum analyzer, bass mid treble and volume controls and input selector. This TDA7419 project is intended for bluetooth speaker project.

TDA7419 project – spectrum analyzer, bass mid treble, volume, input selector

60W MPPT Solar Charger for 14.4V LifePo4

CN3722 MPPT 14.4V LifePo4 60W Solar charger

Here is a simple circuit that I made to charge my 14.4V 4s LifePo4 battery with solar power. MPPT stands for Maximum Power Point Tracking. In a normal PWM solar charge controller, it is basically just a switch which turns on and off when the battery is full, the problem with this is the solar panel voltage drops near the battery voltage hence dropping the output power. With MPPT, it will allow the solar panel at maximum power with the maximum voltage.

PMOS driver for arduino

In case you are looking to make a Buck controller based on arduino, this is a simple circuit to drive the PMOS transistor mainly for buck circuit applications.

This circuit is simple and only consist of NPN and 1 PNP transistor. The circuit above is part of my MPPT solar charger circuit.

4Ch Mini Stereo Headphone Mixer

4 channel stereo headphone mini mixer 3d render

Here is a simple stereo headphone mixer that can be used for monitoring and mixing 2 sources. A very helpful device for online streaming. How? For example you are playing a keyboard on a band in an online stream and using a headphone as monitor. You can use this to mix the headphone output of you keyboard and headphone output of the streaming mixer so you can hear more of your keyboard.

Arduino controlled bass mid treble and input selector with tda7419

If you are looking to control your audio with arduino, here’s it is. It uses TDA7419 chip which has a lot of features for controlling your audio. It has 4 input selector, bass control, mid control, treble control, loudness control and a built-in 7 band spectrum analyzer.

Cheap DIY USB Audio interface for online streaming

In this new normal, most people shift to online content like seminars, meetings and specially churches.

Here is my current project designed to give you better audio for online streaming. It is basically a link to your analog mixer to your computer. It is also known as USB audio interface. What made it different to other products in the market is the integration of sliding fader for better volume control. For church online streaming, you have big volume difference between the band performing and the pastor preaching, the sliding fader makes it easy for such volume adjustments.