Converting a shop unit into a bird house

In recent months, I came to know of another bird nucleus in town. Just established over a year, it is a relatively new area with only 2 bird houses. Both front and back has wide open spaces as roving yards.















As this is not a big exercise, guess it may fit in as another DIY undertaking. These shop houses are 2 1/2 storey. The ground floor has a high ceiling, to its rear is another 1/2 storey like a mezzanine floor.



















So it can be easily converted into 2 nesting floors. Steel beams added to support the new floor areas. The nesting planks too provide additional support to floor boards.



















Behind the roof is an open terrace, another floor extension converts it to a 4-storey bird house. Top floor walls and ceiling were lined with internal layer of styrofoam for heat insulation.
On ground level, the steel roller shutter door was replaced by a double layer brick wall with steel door.



















The equipment room is tappered at one end to maximize internal nesting areas. I don't favor a corner jutting out into the nesting area.



















The roving room extends over the stairway. Stair case roof is removed to provide added entry path. But the wall is retained to control light.



















Workers putting up the ceiling boards of the roving room. The roving room is painted with water based black paint to minimize light reflection to internal areas.















It is pretty straight forward - every bird house is different in some ways, no hard and fast rules & more of exercising common sense. Often swiftlets populated vacant houses/temple attics to begin with. In this instance is at the top of a nearby hospital.

A motorized trolley

As my new bird house is approaching completion. With a ceiling height of 3.5m, a motorized trolley platform reaching up to nesting areas for installation work is handy. It is useful for harvesting and service failed tweeters in future too.

Some time ago, I saw this mini-hydraulic platform at a Melbourne shopping mall - for hire!















Hmm.. wouldn't it be nice to have one to harvest my bird nests? That is certainly wishful thinking!

So this became another DIY project I have been cooking in mind for the past weeks. The implementation idea actually came from my neighbor, P'Wah. He was contracted recently to wire the sound system of some new bird houses. To save him trouble climbing up & down on the wiring job, he built a motorized platform to mount his ladder on.

I took his idea further to have a more secured platform instead. The basic design looks like this. I'll add a few ladder steps during fabrication. You might want to do the same if you have a fair size bird farm building with high ceiling.



















What motor drives & control did he use?
I caught up with him a week ago to learn from his exercise. He is very helpful to share and I expressed my gratitude to him again here.

He used 2 x windscreen motors (12V DC with built-in reduction gears). Use the ones for trucks if you need more torque, he advised. Those are 24V DC. Like a front wheel drive arrangement, one motor each side. The rear wheels are free turning.

The driving wheel shaft is supported by 2 bearings. A rubber coupling serves as a universal joint between the motor & wheel shafts! Simply clever! I'll try to get a picture of it in future.

A typical automobile windscreen motor.













What about the direction control? Joystick I would thought.
"No, I use one finger", showing me his index finger as he replied.

His solution is genius! He mounted 4 micro-switches (one as seen below) with the lever tab facing each other orthogonally (a square arrangement) inside a box. Cutting a round hole, he can put his finger in to trigger any switch to steer the trolley, effectively like a joystick control!
Hmm.. a photo illustration here will be clearer & do away with such cumbersome explanations!
















Each micro-switch is wired for the 4 directional controls:
1) Forward
2) Reverse
3) Turn left
4) Turn right

This is really neat! I could work out the relay controls from there. It is my good fortune to know such resourceful people around.

A conceptual DIY long range bird caller

I have been looking at simple ways to project sound forward too. It is well established that the parabola curve has the property of directing a parallel beam from a focal point. Such application are seen commonly in light reflectors; satellite receiver dish applies the principle in reverse.














It is not a new or novel idea. I've toyed with such a parabolic microphone years ago. It is amazing the clarity of conversations it picked up across the road. Just reverse the application with the tweeter at the focal point, turn it around to project sounds far away.



















Instead of a dish, one can also use a cylindrical shape parabolic reflector to project the sound energy forward as a beam. Seen below is an application of a cylindrical parabolic solar collector to heat water.









Easier to build than a dish, so this is my favorite DIY choice for a long range caller.



















Scaling up its size, I believe it can handle alot more power than a 'bazooka' horn.

By sitting it on a rotating table & also tilt on the vertical axis, the combination can be automated to scan the sky in all directions - like a radar!

Of course, what is the over-powering effect of the high SPL (Sound Pressure Level) at short range?
I have thoughts about its solution too.

This is just a conceptual model.. yet to be tested and proven; one that I have been thinking for a while now. I am pretty sure it will work. The effective range is of course dependent of the applied sound power and physical laws governing sound transmission through air.

Anyone out there game enough to try? I have several more ideas in the pipe line, may sound like science fiction or could be stupid ideas to some! No rocket science actually, all based on applying existing know how.

If the reflector shape is appropriately modified, it could be used for external call sounds to provide a wider beam and reduce noise pollution to the neighborhood.. think about it!

How far can your bird calls reach?

When we do bird calls, normally we would simply turn up the volume knob, wait and watch. Sometimes we see birds circling far above.. they must be responding to the calls, one could only guess.

I have also been pondering how far could one extend the calling range of external sounds?














I guess there is no straight answer to this - it is dependent on:
1) Power of the sound source i.e. to the tweeter
2) How the sound energy is projected in one direction
3) How sound energy is dissipated (or absorbed) while travelling in air
4) How sensitive are the birds' hearing

Well, I don't have all the answers.

As for (1), it is simply the raw power one can pump into the tweeter and how much it can handle without too much distortions.

For (2), it can be improved by design with better engineering solutions. The tweeter horn is to project the sound forward. Then there is the 'bazooka' design to extend the range further.

On (3), I did some readings and gained some insights on the subject.
At room temperature & R.H. 65%, a 1KHz sound travels 35Km to loose 6dB SPL (i.e. half amplitude) through absorption loss!

Sounds good but there is the inverse square law that affects the higher frequencies. What this says is that doubling the frequency would mean the same loss occurs at 1/4 the distance; or a 10KHz sound would be 1/2 level a distance 100 times shorter - to about 350m! A 20KHz sound would be 88m at 1/2 level.

I suppose the bird sounds is within the 10KHz - 20KHz range, so this gives an idea what it is like after the sound leaves your tweeters into the air.

What is worthy to note from above is that the medium of sound transmission, i.e. air itself, has a low pass filter characteristic inherently. Higher frequencies are attenuated much more relatively at further distances. In other words, it loose clarity through the losses of its higher frequencies. So no matter how good are your tweeters, sound quality degrades as distance increases is inevitable.

For (4)... totally no clue! If somebody know something, I would love to know.

A word of caution on mist maker

I just came across mention of such mist maker at another blog...











Commonly installed as part of ornamental water feature with a little fountain, it is wonderful to watch the fog coming out like smoke over water.




















Well, just like to add a word of caution here. I studied its use about 2 years back and decided it is not a good practice.

Why?
Such devices use ultra-sonic transducer that vibrates at around 1MHz! It is the finest fog generating machine, sounds good & I like it initially from that perspective!














Did you know it can pose some health hazard?
Studies by U.S. health authorities had shown that such devices eject fine particles (mineral impurities & bacterias) contained in water into the air as well!

One needs very pure water for its safe use - just take note of this.

Otherwise you may introduce bacterias into your bird house atmosphere unwittingly & unnecessarily.

Suits one of my favorite axioms: Half knowledge can be dangerous!

Cooling the roving room

This is the bird house I've been improving its micro-environment lately. The roving room is long and its design allows 3/4 of it to be converted into nesting areas in future - so it is good to get the temp & humidity close to the desired levels too.



















The data collected showed it is too warm & temp reaching 38 deg around 3.30pm on warmest days with R.H. ranging between 50-60%. On cooler days the max. temp reached 35 deg and R.H. between 60-65%.












My first experiment was to see if too much heat is getting in through the roof. There is an aluminum foil under the roof and some air space between ceiling, insufficient insulation I thought. A sprinkler with timer control was installed on the roof in an attempt to cool it from there. The reduction in room temperature was insignificant. It simply points out much heat came in through the two long side walls.

I do not intend to add more wall insulation at this stage, so how to address the situation?
Good that the humidity was on the lower side. I set up a humidifier in the roving room (near the entrance hole) with a timer control; turned on from 10am to 5pm during the warmest period.

The principle is to extract the thermal energy from the air by using water vapor, similar to misting fan.















Evaporative coolers are commonly seen in countries where humidity is low. It is effective even with high outside air temperature because the heat in the air is being absorb by fine mists as latent heat converting to water vapor.















Humid air vents out through entrance hole via convection air currents. The outcome is quite satisfactory - the highest temp is now between 30-32 deg most days. The humidity is improved too - lowest R.H. of the day is about 75% and highest between 85% to 90% around 5am in the morning.

Logged data with the humidifier in use.












The lowest temperature registered so far is about 25 deg on colder rainy days at about 7am. As a roving room it don't bother me yet. At least I get the day temperature a few degrees lower. It is just a stop gap measure until the time to convert to nesting areas.

Did you know - water vapor is lighter than air?

Every school going kid would know water is heavier than air. Yet many of us may not be aware of the fact - Water vapor is actually lighter than dry air!



















The density of water vapor is 0.804g/litre, which is significantly less than that of dry air at 1.27g/litre at STP (i.e. 0 deg C & 14.504 psi).

If you are not convinced, check it out at: http://en.wikipedia.org/wiki/Water_vapor

What is the implication?
"More humid" air is lighter than "less humid" air. This is what happens in our weather system every day. Warm moist air rises several Km high up in the atmosphere to form clouds.

Somebody labeled this as "stupid logic"..

If you recall the lessons of high school chemistry (elementary science):

Water molecule is H2O - 2 Hydrogen atoms & 1 Oxygen atom -> molecular mass of 2+16 =18 units (neglecting the electrons mass).

Likewise, air is about 21% Oxygen & 79% Nitrogen
Molecular mass of O2 is 16x2 -> 32 units
Molecular mass of Nitrogen N2 is 14x2 -> 28 units

I'll leave the rest to common sense.

What this means to our bird house micro environment?
For simplicity of putting the idea across, let's assume the bird house has the same temperature & pressure between floors. If we create "more humid" air on lower floors, the "more humid" air will drift upwards to upper floors gradually.

How do I made use of this principle?
At a 4-storey shop unit bird house, the 2nd storey has the most birds - i.e. many nestlings are around during the day too. I wouldn't set up the humidifier at that level. What I did was to place the humidifier (with hygrostat control) near the staircase on the ground floor & let the humid air drift upwards slowly.













I did achieve 75% to 80% R.H. most of the time.

Lately, I am testing another approach. I have a dripping tap just enough to keep the ground floor wet but not flooded. The idea is using the floor surface to provide a wide evaporation surface. If this works out well, then the humidifier on the ground floor is not required.

My 2nd DIY Bird sound system

My 1st DIY sound system has been working 24/7 for more than 6 months without a hitch. Now its time to build another.

To recap, my basic system requirements are:
1. High power 4-channel amplifier (100W r.m.s. each). For a small bird house (e.g. a 3-4 storey shop unit), use of 2 channels is more than adequate; the other 2 channels are in stand by - handy without the need to replace the whole amplifier when a channel amplifier failed. I have even chosen those with output short-circuit protection.

2. Back up battery for internal sound in event of mains outage with 2 x 12V, 7AH (more can be added if desired).

3. A 12V DC cooling fan continues to operate in event of mains power outage.

4. Switch-mode power supply (for energy efficiency) to power the sound system & charge the backup batteries.

5. CD sound player with MP3, USB port and SD memory card as standard.

What did I learn from the previous exercise?
The Size 3 enclosure, though adequate, was rather compact to mount two players within. So I up sized it to Size 4. Everything else remains the same.

Two 10 cm fans, one 220V AC and the other 12V DC, mounted at the base.















Seen here a 4-channel (each with 100W rms) amplifier, timer and relay to control the external sound.



















Vertical mounted CD player on swing door.















My neighbor, P'Wah lent a hand on some metal work. He is another DIY man extraordinaire!



















The wired up system undergoing tests - the LED lights looks cool! Forced vertical air cooling; drawn from bottom to exhaust at top PVC vents.



















My external test tweeters mounted in the backyard.



















It turned out the CD players are not suited for vertical mount, so P'Moo re-arranged it back to horizontal mount.



















I have 4 such systems built by now - 2 going to bird houses in southern Thailand. If you are interested in one, please drop me a note here.

July '09 update:
As more of my friends get to know and appreciate my amplifier set-up, P'Jiap has asked me to build him 2 sets. P'Moo will follow suit to convert his amps to wall mount too.