Picture of Motion Sensing Digital Camera & Alarm (a.k.a. the Critter Cam)

Welcome to my instructable on how to make an Arduino-controlled motion sensing camera and alarm!

The motivation behind this project, which I worked on in my electronics class at Pomona College, was the need to keep away varmints (particularly raccoons) that were digging up my parents' yard. Although a simple motion sensing alarm would probably do the trick, I decided to add a camera to the circuit so that I could actually capture the critters in action! I have yet to field test the device, but the results so far are promising.

One really great thing about this project is that it builds upon the work of several other cool instructables:

· Hacking A Keychain Digital Camera for Arduino Control by smb


· Cat Repelling PIR motion sensor (covert) speaker box alarm by briannaw


· PIR Alarm Motion Sensor (with Encasing) by chuck4747


So without further ado, let's build it!

Step 1: Supplies and Tools

Picture of Supplies and Tools

1) An Arduino uno (http://arduino.cc/en/Main/arduinoBoardUno)

2) Arduino software (http://arduino.cc/en/Main/Software)

3) standard usb cable for your Arduino to communicate with the software

4) A 9V battery with an adapter (http://playground.arduino.cc/Learning/9VBatteryAdapter)

5) Digital Concepts “Key Chain” digital camera (costs about $5.50). Can order them from Amazon at http://www.amazon.com/Digital-Concepts-Key-Chain-...

o IMPORTANT: you will need the software installation disk that comes with the camera so that you can install PhoTags express, which allows you to upload your images to a PC (note that you must have Windows 2000/MEXP/Vista 32-bit).

6) Passive infrared sensor (PIR). There are a variety of sensors out there so feel free to choose the one that suits you. For your convenience, I have listed two common models that are compatible with this instructable:

o Here is a datasheet for a sensor very similar to the one I used. The output prong is located between the positive and negative/ground, just like the sensor I used. https://www.futurlec.com/PIR_Module.shtml

o Another model can be found at Sparkfun (https://www.sparkfun.com/products/8630). Note that the negative/ground prong for this model is in between the positive and output (called “alarm” in the datasheet).

7) A super bright white LED. I used http://www.mpja.com/8mm-Super-Bright-White-100000... but there are plenty to be found on Sparkfun as well.

8) One other LED of your choosing. I used this to trouble-shoot my prototype and did not include it in my finished product.

9) A small piezo buzzer (https://www.sparkfun.com/products/7950)

10) One AA battery (1.5V) and battery holder. I strongly recommend a single battery holder. You can order one from Mouser Electronics (here are the results for a search I performed: http://www.mouser.com/Power/Battery-Holders-Clips-...

o If you use a multi-battery holder instead, make sure that you can easily solder an extra wire or two to one of the sockets (Step 4 shows exactly what you need to solder). Battery holders with external solder tabs are ideal.

11) Two relays. I used 8-pin dual in-line package (DIP) relays. A really great example is provided here: http://www.alliedelec.com/search/productdetail.as...

o the configuration of the relay will depend on the model, so be sure to reference your relay’s data sheet to understand how it should be wired up. If you don’t know how relays work, I highly recommend you check out this instructable: http://www.instructables.com/id/How-Electronic-Sw...

o If you’re stuck without a datasheet (like I was), there is a simple way to determine how to hook your relays up (which is explained later in this instructable).

12) two DIP 14-pin or 16-pin sockets (https://www.sparkfun.com/products/7939). I used 16 pin sockets but you’ll only need 14 for your 8-pin DIP relays.

13) One 56 ohm resistor (for use with the 8mm super bright white LED; be sure to check your LED’s typical/continuous forward current and forward voltage so you can calculate the ideal resistance for yourself!)

14) One 10K pull-up resistor (for your PIR sensor)

15) At least 4 arduino stack-able header pins (https://www.sparkfun.com/products/7937) . You’ll need two 6 pin and two 8 pin sockets. I say at least because if you make a mistake during the final soldering process, you'll need backups.

16) 1-2 additional stack-able header pins for your PIR sensor, to place your sensor on your circuit board. These are not required if wires are already attached to the input-ground-output prongs (such as https://www.sparkfun.com/products/8630).

17) Proto-board (for finished product)

18) Optional, but incredibly helpful: breadboard for testing out your circuit before soldering

19) Jumper wire kit (https://www.sparkfun.com/products/124)

20) A few feet of insulated wire, ideally in several colors

21) Wire connectors (you may need them if your battery holder does not have solder tabs; see Step 4 for details)

22) Plastic ties to keep soldered wires in place

23) Optional: electrical tape in several colors (depends on how many colors of insulated wire you have)


· tiny Philips-head and flat-head screw drivers

· wire cutter and wire strippers

· two multimeters

· soldering iron and solder

· solder stand (makes life much easier if you don’t have an extra pair of hands to help you)


This is really cool! Thanks for being so thorough in your documentation.

RTGoldman (author)  craftclarity1 year ago

Thank you! Just wanted to make my instructions as clear as possible.