Author: tataylino

Relay Driver Circuit

Relay are used for driving high current load or if you want to isolate your load from your circuit. For example you want to turn on a 220Vac light using a microcontroller. Your microcontroller is only operating at 5Vdc and your is a 220Vac lamp. The microcontroller can’t drive the 220Vac lamp directly so if you want to isolate the line between the microcontroller and the lamp you need to use a relay. The main disadvantage of using a relay is that you can’t control the brightness of the lamp. Anyway it is also impossible to control LED, and florescent lamp brightness  because of their certain characteristic. LED bulb usually has a built in voltage regulator so it is not advisable to control its brightness, while florescent lamp has minimum operating voltage and it also needs a high voltage to start.

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Audio Mixing Tips

I have been mixing church sound system for quite a while now and I have encountered so many problems and solved most of them. On this article I will share tips to make your sound system sound best.

Most church sound system most challenge is the very tight budget. Very tight budget leads to very cheap sound system and leads to poor quality. Taking into account that most church sound techs are not knowledgeable enough for the job which leads to less optimal sound quality the system can deliver.

On this tips, I will assume that you already know how to operate a mixer and the whole sound system and you already have a sound system in place. I will create a separate post on Mixer 101 and choosing a right sound equipment.

Starting a Mix

sound

So what to do after you have set up and turned on your system? Set the volume of the amplifier to 50% or less. This is to have maximum signal to noise ratio on the line. Setting the volume of the amplifier close to 100% will led to lower signal level and that level may close to the noise level. Take note also that when you set the volume of the amplifier to very low, the tendency is for you to crank up the volume of the mixer and may lead to signal distortions. Set the main volume of the mixer to unity gain(0dB) or just below the maximum. Adjust this when necessary on sound check.

Avoiding Feeback

Bad-Hand-Placement

One way to avoid feedback is to properly hold the mic(above picture). Holding it on the diaphragm(head) will introduce feedback at some conditions. It is like increasing the sensitivity of the mic so it introduces feedback. More information on this Article link here.

 

–More to come…

3W x 2 Class D amplifier

Here’s a simple amplifier that I used for my speaker project. The IC operates at 5V. Note that although it runs on 5V, it can’t be powered via USB because USB can only deliver 2.5W. Ri minimum value is 18k which will give you 24dB voltage gain. The voltage gain is computed by equation : 20 log(2*(142k/Ri))

3wx2amp

Arduino Based Solar Charger

Solar Energy industry has been growing so fast and you can now buy a solar panel or solar powered gadgets almost anywhere. I have been looking to design a solar power system for my home but I can’t find time or I can’t find the best solution to do it. Recently I have been ask to design a high power flashlight for a bike and when I am looking for a charger IC, I stumbled on this one and luckily it is also perfect for solar power applications.

About The IC

The Charger is from Linear Technology’s LTC4015 – Multichemistry Buck Battery Charger Controller with Digital Telemetry System. It has a I2C communication port that can be use to monitor voltages, current, temperatures and battery health. You can also set the charging current and voltage via I2C. You can also use it as a standalone charging IC and wont require any programming. But it is best to use this feature, this will save you space and parts count because you wont be needing an additional current sensors for your application to monitor battery and input current.

Application Circuit

solarCharger

 

Sample Program

You can download the sample program for arduino and other platform below.

 

Downloads:
LT4015 Datasheet
LT4015 Sample Program

Active Crossover Design

Crossover circuit is used to split audio frequencies into 2 or 3 part. There are 2 kinds of crossovers, active and passive. Passive crossovers is use to connect woofer, midrange and tweeter speakers to one source. It basically splits the frequency into 3, bass frequencies to woofer, mid frequencies to midrange speaker and high frequencies to tweeter. Active crossovers is used to split signal going to the amplifier. The benefit of using active crossover is that you have more controls, you can tweak levels and frequencies. The main disadvantage is the cost, aside from the crossover itself is expensive, it will also require multiple amplifier.
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Connecting Arduino Nano to 16×2 LCD

Connecting arduino to 16×2 LCD is very much easy compared to microchips PIC microcontrollers. This maybe because the arduino has lots of software library aimed for beginners. The program is easy to understand, I am sure you can be able to understand it even if you are still new to programming.

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Arduino based Guitar Effects

There are lots of arduino projects that you can find online. But this one caught my eye and I am excited to make my own copy. Since I also love guitars and programming, this is perfect for my next project. It uses Arduino Due as the main processor. This project is published by www.electrosmash.com/ and you can buy the kit for £39.95(not including the arduino due).

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LC75341 tone control using arduino

LC75341 is a digitally controlled analog tone control for audio applications. You can control parameters such as Bass, Treble, Volume and gain through its digital serial data transfer. The data is a 40 bits wide, 8 bits for the address and the 32 bits is the controls data. It is very unusual and you cannot use the microcontrollers built in UART, I2C, etc. I can’t find anywhere on the internet any examples of programs to control this particular IC so I made one for myself. I want to share the code for anyone who want to build this kind of project. The code is simple and I will only share the part of the code that sends data control to the chip. It is up to you to modify it according to your needs.

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TPA3110 class D amplifier

tpa3110 stereo

Class D amplifier has been very popular recently. They are smaller, lighter and very efficient which is very well suited for battery operation. They also require smaller heatsinks than their class A and AB counter parts. This enables you to fit it in a smaller chassis. It also gives more power because the output is normally configured like bridge tied. The only disadvantage of Class D amplifier is that it has higher THD(Total Harmonic Distortion) than its class A and AB counter parts. This is not a problem if you will not operate it on the maximum power.

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