Sunday 13 October 2013

BirdBoxPiCam 2014; #1 The Plan

I bought my first Raspberry Pi mid-2012 with the idea of using it with a bird box camera.

 

Unfortunately there were problems with the EzCap video capture module driver, and I have still not been able to get this going.


However, now armed with a PiCam I'm hoping for better luck with my new project.

Although I've got a number of analogue cameras, these have to be connected through some kind of video capture device (like the EzCap) if you want to use them with a computer. But the new Rapsberry Pi camera is connected directly to the Raspberry Pi (RPi) and produces high resolution video. The downside is that the RPi has to be fairly close to the camera.

The Big Idea

So the idea is to have the PiCam and the RPi in, or close to, the bird box. The system can then transmit video via WiFi and run from batteries.

This raises a number of issues, but I've been thinking about potential problems and doing one or two tests over the last 4 weeks. I don't think any of these issues are show-stoppers, so its time to get on and do it....hopefully in good time for the start of the 2014 nest box season!

The Plan

The plan is to get a workable system ready to install on the side of our garden arch-way by early February 2014.

I may need to make changes or compromises along the way, but here is V1 of my plan.

The RPi+PiCam will probably just stream video (via a wireless router) to an old Lubuntu (Linux) powered computer in the garage. This will run Ken Lavrsen's "motion" application and act as a server, storing video clips for later viewing.

The RPi video stream will also be viewable live via other devices such as a laptop or Android phone. The server will also be wired to at least one existing analogue camera via an EzCap module.

Initial Thoughts On Design

As the RPi is to be battery powered, I may as well use a Model A board. This should save 200mA compared to a Model B.

Other points:-

PiCam

Although there is now an iRed version of the camera (i.e. the iR filter has been removed on the PiNoir camera) I plan to use the daylight version, as I want to get reasonable quality colour video. But one thing that will need changing is the lens. In order to get a full view of the nest I will need a 90deg angle of view (probably a 3.6mm lens).

L.E.D.s

There won't be enough natural daylight in the box for PiCam, so I need to supplement this with a few LEDs. This has to be done with care and sensitivity.

During the night the lights must be turned off, and during the daytime the lights should not shine into the eyes of the occupants. In the first case the LEDs will be controlled via outputs on the RPI. (In any case the battery will probably be removed for changing over night).

Where I've used LEDs in the past I have avoided glare by painting the inside of the roof white, and pointing the LEDs upwards.

Entrance Counter

This is something I'm already using. Its a simple light-beam circuit including an LED and photo-transistor. I record the number of times the beam is broken to deduce the level of activity.

Temperature Sensor

I've measured bird box temperature before using a thermister. To be honest, I wouldn't bother to do this again if I had to worry about including some kind of analogue/digital converter. But the RPi can use a 1-wire sensor, so I thought this would be a good excuse to try one out.

It also occurred to me this morning (while in the shower) that the temperature in the bird box I plan to use, has risen above 35deg C in previous years. So maybe the sensor should be monitoring the RPi, rather than the birds.

The SD Card

I still have not decided whether to store captured video clips on the SD card, or just to leave that to the Lubuntu box. This is probably the only decision that will affect SD card choice, at least in terms of capacity.

WiFi Dongle

I'll be using my existing Edimax EW-7811UN which is an n compatible device (up to 150Mbps). I may need to swap out the old Netgear (g) router in the garage for an n type if speed/bandwidth is a problem.

5Volt Regulator

I'm thinking of buying a dirt-cheap car (cigar lighter) power unit and cracking it open with a hammer. I can solder on a couple of leads + crocodile clips for the 12V battery connections (probably cheaper and less hassle than making one).

Battery

I recently acquired a 12V 4Ahr battery so will start with this.

More To Follow

So in the next few weeks I will be adding more posts on this project.

Use the search function at the bottom of this page to find related posts. Just type in the search word: BirdBoxPiCam2014

3 comments:

  1. I used SHT75 sensors with the arduino, but DS18B20 1-Wire Digital Thermometers worked well when I was playing around with the Beaglebone.

    This time around, for all the hassle of implementing and testing my own datalogger, I'm looking at standalone button loggers;
    http://uk.rs-online.com/web/p/temperature-humidity-sensors/7327504/

    How efficient is the cigar lighter reg? http://uk.rs-online.com/web/p/switching-regulators/6727155/

    (There is a cheaper 1A version which you should be able to get a away with using the model A... depending on the wifi and LEDs.)

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  2. Yeah, you are right, I should be building my own. But when you see cheapies like this: http://www.amazon.co.uk/Two-Port-2-1A-USB-Charger/dp/B005JCPZ22/ref=sr_1_12?s=automotive&ie=UTF8&qid=1384590346&sr=1-12&keywords=phone+charger+for+car
    ...it becomes a challenge to work it into your design. A dissatisfied customer says "...generates chronic RF interference..." so it has to be a switching reg. Another says: "...had a major mechanical design fault..." so it deserves to be cracked open and hard wired.

    The temperature sensor will only make it into the 2014 box if I get my skates on. I built & started testing the auto power-on circuit (triggered by activity) last night. In standby it draws less than 4mA plus the current drawn by the IR tigger (which I calculate should be about 8mA). When turned on it still only draws 12mA (+ IR current) which is nothing compared to the RPi + led lights power.

    I wonder if you could make use of this idea if you had up-stream & down-stream sensors in your tunnel?
    Even better if we could get the RPi to boot really quickly (say, under 10 seconds).

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  3. You have shared a great information about Underwater Video Cameras and Bird Box Cameras.Which are very informative for us. Thanks

    ReplyDelete