Choosing a Webcam

During the last few years there has been an increase in the number of people interested in setting up their own nestcams and in response to a suggestion I have tried to set the options  that need to be considered by anyone who wishes to share the magic of watching the nest building and family life of a garden bird.

1. Where to mount the camera:

(a) In the top of the box..

The most popular arrangement is to have the camera mounted at the top of the
box, looking straight down on the nest.  Several companies sell ready-made examples of these, most of which are rather expensive. I have not used this approach, but some users have experienced various problems that affect the quality of the image when setting up their home made versions.
When you mount the camera inside the lid of the box the first problems are to mount the camera at the correct angle and adjust the lens to pre-focus on a set distance, You need to predict where the best position will be before the subject is there to check it, for example, focusing on where you think the top of the nest will be means that the bottom of the egg cup will not be clear.

(b) Mounting the camera at the side of the box..

Alternatively you can decide to mount the camera to give an oblique, or side view - this is a more complex arrangement, but I have found it more rewarding as it can give a view that is more 'natural'. A suitable box can be built on the side of a shed so that the camera is mounted inside the shed so that adjustments can be made at any time. This has the advantage that you can watch the box directly as long as you can made the shed dark.

The method has its own particular set of problems, the main one being the problem of keeping the camera lens clean. This will be best solved by including a glass window between camera and nest. However, the glass will need cleaning and any box construction needs to take this into account. I use an arrangement by which a clean glass can be slid into place as the dirty pane is removed, without creating an opening into the nest.

It is generally recommended that in open garden situations the sector from North through east to south-east  is best for nestbox entrances. The orientation of the camera in relation to the relative positions of the box entrance and the sun during its daily movement can cause a problem. For example, if the box faces east and the camera points in the same direction (as mine does) then there is a problem of extremely bright conditions on a sunny morning. With the box entrance facing east it might  have been better if I had been able to put the camera(s) on the south side of the box.
 

The Camera -

(a) Power supply

Whatever camera you choose will need power. Most require a 12Volt supply which makes them safe for use in a birdbox when used with a suitable power supply. If you buy a secondhand cctv camera, older models often require a mains (240v) supply.

(b) camera type

What type of camera would you use? A favoured type used in boxes is the board camera, which is basically a camera on a bare circuit board, There are also mini-cams which are similar, but enclosed in a protective case. Some cameras are waterproof . I see that it is now possible to buy different focal length lenses for board cameras, giving you the option of different angles of view - something to think about if you are going to design a box around it.

If you have more space (as I have with my 'walk in' birdbox) then it is possible to use C/CS type cameras which use interchangeable lenses. In my arrangement I am able to move the cameras about and make adjustments without disturbing the nest.

(c) Camera Resolution

On commercial sites the resolution of the camera sensors is usually shown as TV lines. The higher the number, the better the resolution and the more satisfying the image. Some very cheap cameras have values less than 380TVL. I would not recommend buying a camera without a resolution lower than 380TVL - there is nothing more disappointing than going to the bother of setting up your webcam only to have a image that lacks sharpness even when the camera is focused.

 

(d) Camera Sensitivity

The sensitivity of a camera to visible light is usually given in lux. To give you an idea of what that unit is:

The brightness of sunny daylight is  >10000 lux

The amount of light falling on a surface 1 metre away from a candle is about 1 lux
Full moonlight is about 0.1 lux
Starlight on a clear night can be up to about 0.01 lux.

Good B/W cameras will be sensitive to visible light down to light levels of around 0.05 lux, although this 'limitation' does not apply to infra-red light.

Colour cameras are sometimes sensitive down to around 1 lux, although by then the image is usually quite poor. A few will go down to around 0.5 lux

(e) Colour or Black/White?

Do you intend to use a B/W camera or Colour? B/W has the advantage that it can be used with infra-red lighting and so will provide an image day and night with no visible light in the box.

Colour has the obvious advantage of being in colour(!) but needs an adequate level of visible light, so that when you are looking at purchasing a camera you need to find out how sensitive it is in low light levels - the more sensitive the camera, the less light will be required.

There are cameras which offer a day/night feature, switching from colour to B/W when light levels drop below a certain level. These are more expensive and the specifications I've looked at suggest that the change-over to B/W occurs at too high a light level for my liking.

(f) Light Sources

Some cameras have LED light sources built in, usually infra-red versions for B/W cameras or white LED's for colour cameras. These are the most straight forward to install.

However, numerous people have had problems getting the light levels satisfactory because the light sources were not intended to be used at the short distances found in a birdbox.

Also, LED's usually act more like spot lights rather than flood lights, giving 'hot-spots' and corresponding dark corners. Translucent plastic can be used to help solve these problems.

The interior of the birdbox can experience extremes of natural lighting throughout the day and night. For example, if the box faces east then for a period after dawn sunlight can enter the box, creating  very bright areas and dark shadows. By the afternoon the levels will be lower but more even until it starts getting dark in the evening. However, periods of dark clouds/heavy rain can mean low levels at any time of day.

This means that a to maintain a consistent level for the camera, a light source needs to be on during the day. If that source is I/R  then it can remain on constantly. However, if a white light source is used for a colour camera you need to think about how and when that is turned off at night. This will be a problem if the white LED's are built into the camera.

In my experiment with a colour camera this Spring (2003) I used an white LED torch (with a plastic diffuser from a camping shop and soldered wires to it in order to operate it via a mains adaptor. This was plugged into a timer switch. Over the months the timer had to be adjusted to cope with the longer days. In tandem with that I used an IR light source which could be left on permanently.

(g) Cabling

There are going to be two cabling requirements between the box and your TV or computer, a suitable cable for the picture signal, and a power supply lead (usually 12v). Some camera kits are sold with combined leads, although you need to ensure that either these are long enough, or there are extension leads available, the connection being kept dry.

There are camera kits with a wireless link for the picture. I have no experience of these. However, you should remember that the camera still needs a power supply, and it will be important to know whether or not it uses legal frequencies to transmit the image.

(h) Sources of cameras for birdboxes

None of the camera equipment that I use was bought new, but I have found the following two commercial sites to be very information about  the types and specifications of suitable cameras available in the UK.

http://www.rfconcepts.co.uk/  and  http://www.henrys.co.uk/electronics.htm

The following sites offer ready-made birdbox/camera combinations:

http://www.boxwatch.co.uk

http://www.eco-watch.com/


I hope that I haven't complicated things too much. It becomes much more straightforward once you have the camera sorted. If you have that in your hands then you can design the box around it to get the optimum performance out of it and great daytime TV for several months each Spring.