Introduction: Camping/Outside Alarm System for Detecting Beast and People

About: Hi, I'm Tamas. I like to build all kinds of electronic gadgets, hope you'll like my ideas. I'm not so active on the site these days, so sorry for the late replies. (Oh, and sorry for my broken English in these…

Now is summer, lot of people are going enjoy the wildlife while camping in the nature. If you ever slept in the nature in a tent you know how formidable is to hear the noise of any beast in the darkness, (example a bear). There are some techniques to flee from a bear but the best is remain far from them. The anilmals in the forest are usually hunting at night, when people are sleeping. Here in Center of Europe the forests are full with beasts who live in piece together if we don't disturb them.

If the animals can smell the food in your tent they'll try to eat something from it. These animals are stronger, faster, and bigger then you usually, but we are smarter then them! That's why I invented this solar powered automatic alarm system that can detect move and alarms you with the build in light and buzzer.

This is a inexpensive gagdet, that can save your life. The full costs was less than 20 bucks.

Some technical specifications:

  • Build in 2200mAh Li-Ion battery
  • Solar Energy Powered Charger
  • Long Range Move Detection
  • Build in Speaker and Light
  • User Friendly, Easy to Use
  • Full Automatic-only one power switch is needed
  • Easy to Fixwith the Help Of Magnets

You'll need some routine in electronics, but it's not hard to build. Please if you think that this gadget is useful or a good idea give a kindly vote for me.

Step 1: Tools and Materials


  • soldering iron, and solder
  • crafting tools
  • glue/glue gun
  • wire cutter
  • rotary tool


I'll try to give link for the most important parts, I hope will be useful:

  1. PIR Sensor
  2. 18650 Li-Ion Battery
  3. Li-Ion battery Charger
  4. 5v Solar Panel
  5. LED Board
  6. Wires
  7. Switches
  8. TL497CP, 9v step up IC
  9. ferrite core
  10. 555 timer
  11. 2x BC547
  12. 1n4007 diode
  13. 12v relay
  14. 100 ohm resistor
  15. 220 ohm resistor
  16. 1k resistor
  17. 100nF capacitor
  18. neodimyum magnets
  19. USB male/female connectors (for the battery charger)
  20. IC holder
  21. 8 ohm speaker
  22. a project box
  23. 2x 9v battery clips
  24. 100-1000uF capacitor (any value)

In the next step I'll explain the working theory of this device, but if you have any questions fell free to ask!

Step 2: How It Works?

  1. Solar Charger: The battery can be recharged with a solar panel via a LI-ion charger circuit. See the first part of the circuit.
  2. 9v step up: We need to boost the voltage to at least 8 volts because anyways the 12v relay won't work. But if you have a 5v relay you can skip this part. I used a TL496 CP integrated circuit to boost the voltage to 9 volts.
  3. PIR Sensor: This sensor is able to detect move. Amplified the output power with a BC547 transistor (or equivalent) so the relay can work perfect.
  4. 555 Timer High Frequency Oscilliator: This part can be skipped if you have a passive buzzer. But I haven't so now I needed to make this circuit.

The light and the buzzer are connected to the output of the PIR sensor circuit.

Step 3: Prototyping and Experiments

I made some experiments before designing the full circuit, but you can skip this step. I used my oscilloscope to design the most irritant sound in the highest frequency. This is important because animals hate high frequency sounds so we hope they are receding from it. I made my experiments with a 9v battery.

Step 4: Solar Panel and LED Board

This is the easiest step, just solder the wires to your LED board and solar panel. Now they can be used in the circuit. These parts will be placed outside the box so use strong wires.

Step 5: The Battery and Charging

Solder the female USB connector to the solar panel. Then solder the 9v clip and the li-ion charger circuit to the battery. To input of the li-ion charger circuit is connected a male USB connector, so you can charge up from a wallplug. Now wrap everything into ductape . The battery now is able to be used.

Step 6: The Circuit: 9v Step-Up

Important: Here you can see a USB connector, but this is modified later to a 9v battery clip. Please sorry for this mistake.

I haven't more pictures about this part because my camera discharged, but is very easy to build this circuit. The diagram shows every connections: pin 7 and 5 are connected to the GND, the voltage IN is connected to pin 2 and to pin 6 with a 40uF inductor, then the output is connected to a 470uF capacitor. The output voltage is 9.04 volts for me, this is enough to drive the relay and the sensor.

Step 7: The PIR Sensor

Add the parts to the circuit then solder everything to the right pin. The RED and BLACK wires are the minus and plus for the sensor. And the white wire is connected to the collector of the BC547. The base is connected to the output pin of the sensor through a 100 ohm resistor.

Step 8: The Relay

Solder the relay to the emitter of the BC547 and the other pin to the positive 9v pin. If you're done you can test your circuit. Connect the battery to it, and if you move you can hear a "click" that means that the relay works. The relay has two pins for the switch inside, solder here the positive 9 volt pin, and the other pin is going to be connected to the LED board and the oscilliator. Now if the sensor detects move the relay will be swiched ON.

Step 9: The Frequency/Tone Generator

First of all solder the positive wire from the relay and the ground wire to this part of the circuit board. Then add the parts to it. The potentiometer can be used to change the ouput frequency.

My soldering iron was very bad so I can't make a good quality circuit but it works. I bought a new soldering iron but still isn't arrived.

Step 10: Sound Booster (Not Needed, Only My Speaker Was Bad)

This step is made to explain that small circuit between the speaker and the main circuit. I used an LM386 IC to boost the output signal, because my small speaker wasn't enough loud. If you make this project you DON'T NEED TO DO THIS.

Step 11: The Speaker and LED Board

I used an ON-OFF-ON button switch to set the light and sound. This connected to the positive output pin, to the speaker and to the light. Then connect to the ground everything.

Step 12: The Full Circuit

The circuit needs to look like somehow on the pictures or a little bit better. Works without problems, the max range of the sensor is set to 9 meters, and the alarm time is set to 40 seconds.

Step 13: The Box

A found a plastic transparent box at home and I used this to make a waterproof case for the circuit. Drill holes for the sensor, for the switches and for the wires. It's pretty easy.

Step 14: Glue Inside the Circuit

I used hot glue to fix the circuit. The solar panel's wire and the LED board's wire needs to come out the box

Step 15: Magnets

I glued neodymium magnets to the parts, so can be fixed easily to any metal, like an eaves or the top of your tent.

Step 16: Done-Ready to Alarm

Now you're done go outside and test it.

Step 17: Testing and Finish

I've tested every funcion and worked well. Thanks for reading and for patience. Hope you think that this device is a useful invention, and don't forget to give a vote if you liked!

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