Friday, 25 November 2016

VNC (Virtual Network Computing) for Raspberry Pi

It's been awhile since my last post. Today, I will talk about the VNC of Rpi. This post was cited from this link.

Headless Connection

By using this method, we do not need to connect the Raspberry Pi to any keyboard, mouse and monitor. You can access it from any PC, Android device or iOS device.

My current Rpi setting: 


1. Raspberry Pi Ver3.
2. Wireless Dongle
3. Power adaptor


1. Install SSH software in your Raspberry Pi. Please refer to this link for details.
2. Find the IP address using command ifconfig. Please refer to this link for details.
3. Install tightvnc in the Raspberry Pi. Please refer to this link for details.
4. Setting fix IP address for Rpi. command nano /etc/network/interfaces and add under wlan0 the text below:

5. Restart and install VNC on your PC and gadget. It is available at playstore for Android device.

6. Done. You are ready for VNC of Rpi.

Please contact me if you more information on the setup.

Stay tune for more posts.

Monday, 22 August 2016

Control DMX Lighting Using USB Interface


Have you ever think of using PC to control DMX lighting fixture instead of using DMX mixer? Recently, I bought lighting fixture and USB to DMX converter to try control using PC.

Item Required:

1. USB to canon jack (DMX).

2. Lighting fixture

3. Freestyler software

This software can be downloaded from: It is free for download. However, you can choose to donate to the developer.


1. Connect PC to DMX lighting using USB cable. Launch FreeStyler software, at the interface setup choose uDMX and click save.

2. Next, go to add and remove fixture. Choose the lighting fixture that is similar to the one you connected. For example, if it is 6ch. Choose other brand with 6ch, it is fine.

3. If you have more than 1 lighting. E.g: 10 lighting fixture. Split it, 5 left same address A001 and 5 right same address A009. How to set the address? The address is shown in the fixture in dot matrix display or DIP switch. Click this video for setting up address.

Figure below shows the lighting fixture address.
Note: Most of the lighting fixture has own program. E.g.: static colour light, fade in out light, fast transition light, sound detector light and etc.

4. After all these are done. Now, lets go to program a chase/ Cue. Select different colour of light, click add step. Select the desire fade and speed. Once done, save it as cue.

Once done, try it and you will like it. Go to CUE page and the speed of the CUE is adjustable as per highlighted part.

I have done my demo in one of the church in Kuching. Please click on this video.

And my PC setup looks like this:

If need further advise and suggestion. Kindly contact me. Thanks

Sunday, 12 June 2016



On the Year 2013, I attended the Chargeman Underground cable course. The Chargeman course required strength in practical. It is the same and apply to all Chargeman related courses. The basic requirement for the Sarawak Regulator, Electrical Inspectorate Unit (EIU) is that the person needs to have at least 3 years experience in electrical field.

For those who has Degree in Electrical Engineering, taking this course can be helpful when you go for BEM PE interview or even Electrical Supervisor/ Competent Electrical Engineer in the future.

The Course Content (Theory)

Section 1
1. Electrical Safety & Electricity Rules
2. Underground Cable Basic Testing

Section 2
1. Conductors
2. Conductor Screen
3. Cable Insulation
4. Insulation Screen
5. Bedding
6. Armour

Section 3 Cable Laying Methods
1. Cable Laying Methods

2. Direct Laid System
3. Duct Laid System
4. Site Inspection and Trial Holes
5. Minimum Installation Bending Radii
6. General Wiring Cables
7. Laying Cable in Pipe and Duct
8. Protection Cover

Section 4
1. Conductor Lossess
2. Skin Effect
3. Proximity Effect
4. Sheath Losses

Section 5
1. Cable Sealing
2. Installation of Cable Sealing End Caps
3. Cable Seal XLPE and Lead Sheaths
4. Civil Works

Section 1 - 4 come out in the exam.

The Practical
1. Cable Sealing End Caps

2. Flaking and Unflaking of Cables

3. Cable laying

Please click video for the short clip on CH U/G practical.

If you need further explanation, please contact me by email:

Tuesday, 12 April 2016

Raspberry Pi Customer Satisfaction Survey

This is a simple project to capture customer satisfaction survey using Raspberry Pi. This survey only has 5 rating ranging from very poor, poor, average, good, & excellent.

Figure 1 Rating of Customer Survey Satisfaction

Material Required
Figure 2 Raspberry Pi connected to push button & 16X2 LCD

1 - Raspberry Pi Ver B.
1 - LCD Monitor, 1 - HDMI cable, 1 - 5V Adaptor, 1 - keyboard, 1- Mouse, 1 - Wireless Dongle
1 - Breadboard
1 - 5 Push button (5 rating selection)
1 - IDE Cable
10 - Male to male jumper

Source Code & Result
Figure 3 Declaration of GPIO for both LCD, Push button, & LED

1. Once a customer finishes his/ her consultation with the customer service personnel. The person will ask the customer to rate the customer service by pressing on the push button.

2. When the customer press the push button for 1s (e.g. Average). It will appear on the LCD screen, LED will ON for awhile and captured at the data log.

3. In the end of the month, the officer in-charge can tabulates it using excel sheet.

1. Reduce paper work
2. Convenient and more I.T savvy

Figure 4 Data Log Captured with time frame

Short Video Clip:

Figure 5 Video clip of the system

Please contact me at:
011-38660076 or
For more information on the source code and hardware

Thursday, 17 March 2016

Sound System for Studio in Gymnasium

Welcome again to Audio & Visual blog, this week I would like to share with all of you regarding the sound system for the studio. Before that, what is the criteria for it?
1. Less humming
2. Good quality cordless microphone
3. Good Sub woofer for better bass (keep the people excited and more energetic in exercise)

Case study, give comment and improvement on one of the exercise facility (gym) in one of state in Malaysia.

Figure 1 Mixer and Amplifier of Sound System

This set of sound system looks okay. It comes complete with mixer, compressor for the main speaker, amplifier, cordless microphone, DVD player.

Figure 2 Closer looks of the mixer (4 Channels)

Figure 3 Two types of transmitter are used in studio

Figure 4 Type of microphone used

This set of system is okay but however, the type of wireless module used are not good enough in such a way that the sensitivity (gain). Turning on too loud will cause humming/ feedback.
I suggest to use better wireless module (e.g: Senheiser or Shure) and the better wireless microphone (e.g: aeromic).

Instructor is the person that required good microphone during the exercise. This is important when sweat stick on the microphone cable and microphone. Hence, it is essential to have sweat proof microphone and the wireless module (transmitter) to be attached behind the microphone. Figure 5 shows the recommended microphone to be used by instructor. He/ She will not feel the cable disturbing and more convenient in teaching the class.

 Figure 5 Suggested wireless microphone

Stay tuned for more blog.

Sunday, 14 February 2016

Loud or Soft Monitor Speaker for Vocalist in the Church's Setting?

It is quite common for backup and worship leader to say "Guys, I cant hear myself can you boost the monitor volume". Does monitor volume so important and affect the worship session?

What is a monitor speaker?
Monitor speakers are designed to provide a flat frequency response so that that the audio signal is in original condition. The default monitor design does not have artificially boosting bass, treble or other frequencies to avoid resonances from the speaker and sound "nice".

Figure 1 Sample of Floor Monitor with Wedges for Vocalist

There are two types of speaker, based on where the signal is amplified. The characteristics of each type is described below.

1. Passive speakers

This types of speaker only provide basic feature of a speaker, in other words without built in amplifier.
Figure 2 Passive speaker setting

2. Powered speakers

This types of speaker does not need any external amplifier. It has built in amplifier and power cord needs to be connected to it. It is also called as active speaker. Most of the portable speaker is this types of speaker.
Figure 3 Active speaker setting direct from mixer

Figure 4 Active speaker setting direct connect to Microphone

Let me share with you the case happened in my church for vocalist floor monitor. All three monitor shared the same line/ Aux and it has caused inconvenient to everyone. Worship leader always complaint that the backup singer is louder than him/ her during the worship session. Nevertheless, backup singer also complaining not hearing themselves. In this scenario, shall we 'sacrifice' the backup singer and focus on worship leader only?
Solution 1:
Split the monitor into worship's leader monitor and backup singer's monitor. In this case, the worship leader will have his own monitor and backup singer will share one or two monitor among themselves.
Solution 2:
Always set the volume of worship leader louder than the backup singers. Take note that the backup singers volume must be satisfactory to them.
Solution 3:
In ear monitor for each singers on stage.

In the end, I chose solution 1 because that is the cheapest way (without purchasing new equipment, perhaps just one cable)

How to ensure the monitor volume is suitable?
When performing sound check, sound man needs to lower the volume of FOH. From there sound man will fix the suitable volume for the monitor based on singers feedback.

For more information, kindly contact me. Kelvin Yong

Friday, 5 February 2016

Wedding Service Handling Audio & Visual

Time flies and it now near to Chinese New Year, year of Monkey, 2016. Well during this time, many are preparing to celebrate CNY.

On the 30th January 2016, I was invited to be in charge of PA/ mixer for a event of wedding. It was held at First Baptist Church, Sg. Tapang at 10:00PM. Before the actual day, a simple rehearsal was conducted.

Basically, the event start with guess entering, followed by bride enter the hall, and followed by worship, ceremony.

The part that required a lot of mixing is during the worship session. There is two group for worship: 1. Full band with electric guitar. 2. Sentimental group with piano.

1. Full band with electric guitar
Only one vocalist, however there are many instrument: keyboard, acoustic, drum and electric guitar. I emphasis on electric and acoustic guitar because it sounds better. Keyboard is playing background music which is only suitable during bridge and verse of the songs. For electric guitar, he is playing distortion at all time.

2. Sentimental group with piano
Only one vocalist, she has strong and sharp voice. She is accompanied by grand piano, bass guitar and drum. Overall comment for her is good, maybe because of her voice that is easy to be tuned.

The photos taken are as below. You are welcome to contact me if any of you are interested to hire me to mix during your wedding event.

Wednesday, 3 February 2016

Operating Procedure for handling Audio & Visual in a Room

It is always not easy to handle audio & visual in a room/ hall. Imagine as a sound man, you are alone in a room with lighting system, sound system, projection system, and recording. Yes, that's right. You will go crazy with all and will be super busy.

How to handle if you are facing this scenario?

Sometimes I also faced this problem. I suggest that:
1. Lighting system - keep only one simple scene without case
2. Sound system - keep the mic volume ON & playback volume ON
3. Projection system - the personnel will be handling the PC for projection of songs during the worship session

In the church, I have come out with a simple operation manual. Hopefully, it will be able to guide those not familiar with the audio & visual to operate it.

Kindly click on the link for the sample of operating manual for a room.

Thursday, 28 January 2016

The Marriage Course 2016 (Mandarin)

On the 3rd January, I was invited to be in-charge for audio and visual for one event.

This event is called The Marriage Course by Alpha. This course is conducted by running the DVD. The speaker of the DVD is Nicky and Sila from U.K.

Hence, in order to run this program. Items needed are as below:

1. Mixer/ PA system
2. 2 Units of DVD player OR Combination of 1 Unit DVD player and 1 Unit Laptop
3. 2 Units of pair of Red & White RCA cables OR 1 Unit of Red & White RCA cables & RCA to audio jack cable
4. Projector

The pictures are as followed:

 Figure 1 Mixer Used by FBC Chapel

 Figure 2 Laptop Used by FBC Chapel

Figure 3 Audience during the Event

This event will last for 6 weeks and the participation is very encouraging.

Monday, 25 January 2016

Experience in Audio and Visual

Welcome everyone to my blog Audio & Visual World!!

Blog Introduction:
I share my experience in lighting and PA system that I have used before. Furthermore, I will review on the advantages and disadvantages of it. Beside that, I will be sharing on the headphone, audio jack, and other necessary items related to audio and visual.
Stay tune for more information and more posts.

Author Introduction:
I have been handling audio and visual for more than 10 years, I started at the age of 16 years old.
It is not easy to start mixing on the mixer. To be a sound man, a person needs to be able to handle stress and alert whenever there is feedback (humming).

Sometimes a sound man needs to handle special request from the musicians and audience. For example, a musician tells me that she cannot hear herself from floor monitor which she is standing far away from floor monitor. In this situation, should I tuned louder for her or I just asked her to stand nearer to monitor. This is the example of dilemma situation, the solution is to ask her stand nearer to the monitor. If I tuned the volume loud enough that she can hear herself, it will cause humming and too loud to other musician and singers.

For your information, I started mixing in a church setting, First Baptist Church in Malaysia. This church has instrument from drum to guitar. However, the preferable for the church's setting is soft bass and clarity in volume. Figure below shows the sound system used during the old time before 2007.

 Figure 1 Compressor & EQ Behringer and EQ Ashly

Figure 2 Mixer Mackie

Stay tuned for more posts from this page.