So what's the crazy idea?

See my huge 10" diameter "Super Bazooka" under construction! It makes some of my friends laugh!



















To be driven by 8" drivers, compare size with the 12" ruler.



















If that's not enough, I've added 2 more 4" drivers on both sides (like rocket boosters) for extra punch! That's really crazy but fun. Just want to find out how far can I project the bird calls. We did a quick test, not at full blast of course. Birds did came but no big deal.

At close range the SPL (sound pressure level) could be so high that causes hearing damage. That's another problem I can solve.

How far can swiftlet sounds be projected by tweeter?

This is a question of curiosity I had for a while. I did read about how the atmosphere attenuates different frequencies unequally over distance. I don't have a definite answer until tests conducted.

This would be one interesting up coming exercise. I surveyed my area for a quiet spot a good distance away. There is clear line of sight to my roof top without obstruction. Estimated its distance on Google Earth to be 2.63 KM. Once told Pak Hen I want to make a long range caller to go 5KM. He looked at me and said, "You are crazy!" Well, looks like I can contend with half range to begin with. He is correct, now I think I am crazy too.















Like to see if my long range tweeters can project sound that far! It's also about pushing the envelop.

The last time I did field tests was with Victor (of Yen Yen blog) back in Singapore at perhaps 300 meters. An industrial area void of residents was chosen and test conducted late at night. Even then volume was not turned on too loud as it drawn on weary passerby. Those were normal tweeters tested, ones used for external sound. Just a simple listening test with human hearing.

Tweeter Testing - part 1

Of late I have been reading what people in swiftlet farming community said about tweeter performance & tests. At best are some comparative tests using a certain bird sound played over a few tweeters, record the sound and use software to plot its frequency spectrum. Some published test charts but could not even explain them properly. These are not proper tests which shall be evident later.

There is a lack of discussions on how tweeter should be tested.

The coming weeks I will be testing a series of tweeters. In the process I'll work on a DIY kit so you can perform tests on your tweeters too.

To begin with, the sound source should be a pure sine wave of constant amplitude (volume). It's frequency changes gradually over the test range. I've found a video clip to illustrate this. The sweep frequencies are from 20Hz to 20KHz. The waves are of constant amplitude throughout; however it does not appear so at higher frequencies. You will see the amplitude fade off at some stage and later wave patterns develop due to sampling effects. This is because the computer display is not fast enough to cope. Only an instrument like an oscilloscope will show it properly. It is the same when I played my test signals on the Windows media player.

Harvest Trolley - dimensions

An update on re-sizing the trolley. I like the way it is of the prototype, but my friend P'Wah think it should be more compact. The proposed dimensions are:

1. Platform size: 0.8m x 0.8m
2. Platform height: 1.5m, adjustable in 10cm step to 1.7m
3. Base 1m x 1.5m
4. Wheels size: 6" (as suggested by Justin)

This is what it looks like: (man height in drawing is 1.67m)
N.B. The cross braces are left out of drawing.



















Any further comments or feedback?

Another helpful feedback from Justin - for a wider wheel base. Thanks for the illustration too.



















This can be DIY build with angle iron available from local hardware stores (as our prototype). We find it cumbersome to move it for use between floors. So our preference is to build with aluminum, to be light and easy to disassemble.

Alternatively, each floor can have a trolley and move only the motor drives. If you need motors & control, please PM me at chng.charles@gmail.com

Thoughts on future direction of this blog

This blog has been in existence for slightly over 2 years now. It served as a channel to share some of my thoughts and activities. The future path is to find new and better ways to improve the operations and management of bird houses - tried and tested solutions along with proven products shall be featured here.

In my view, there are many myths & half truths propagated out there in cyberspace. An example is the selection of tweeters; not many folks can tear through some of the technical spin around it. The best choice is to derive from real experiments with birds, not merely based on technical discussion & specs. This is certainly one subject I would investigate further with comparative tests.

What's more? I intend to convert solutions into products such as the motorized trolley in development.

What's the intention? I am setting up a fund in aid of building a technical school in Sangklaburi, a remote town near the Thailand & Myanmar border. This is not my personal project but would contribute some efforts to its realization. Profits derived would be channel towards this cause.

Some may have come across this in my other blog:
http://my-swiftlet-farm.blogspot.com/2010/11/visitor-on-special-mission.html

If you like to find out more, please visit these blogs:
The fund raising walk:-
http://walkforeducation.wordpress.com/

The Technical School Project:-
http://prsarkartechnical.wordpress.com/

I hope that if you find my blog informative & useful, be kind enough to contribute too. In return I offer services in areas of my competency.

Bird nest harvesting trolley test drive

Having given the battery a new charge, the motorized trolley was rolled out for a test drive.

Here you see my friend P'Wah took it through various paces - forward, turning & reverse movements. He seem pleased & me too!


We would develop it further as a "knock-down" version for ease of transport & assembly. Your inputs to its refinement are most welcome. Our primary objective is a convenient & safe platform to work on.

Bird nests harvesting trolley

Well, my motorized trolley has finally got off the drawing board!
Designed for dual purpose in mind - bird nests harvesting & to inspect/service the sound system.

It is timely as a friend fell off the ladder while harvesting bird nests 2 weeks ago. He simply mounted a ladder on wheels and has been using it for a long time! It never appear safe to me however. One day his son pushed a little too hard accidentally and he lost balance at the top. He jumped off and had a bad landing - broke his leg and shoulder blade. Seem like Murphy's law repeating itself again - "If it can go wrong, it will eventually!"

The prototype is built with angle iron for ease of assembly. Though designed for one, it can actually accommodate 2 persons. A shelf is added to place tools when used as a working platform. A commercial version will be develop next.



















The motors (with reduction gears) are driven by 12V car battery. Photo showing the universal coupler connecting the motor & wheel.













The joy-stick with micro-switches arrangement for directional control - forward, left, right & reverse. I've found an industrial grade version for the final design.



















Look forward to its test drive on video next.