• Ever wanted to catch an intruder when they trip a laser beam?
  • Want to know how many times your pet (or anything else) is going in and out of your house?
  • Someone sneaking into a place they shouldn’t be?
  • Like to play with lasers, mirrors, sensors, duct tape, and/or dry ice?

Using Valarm with a Yoctopuce “Yocto-Knob” allows you to DIY a powerful, internet + SMS connected, home alarm system, by connecting your Valarm-equipped Android device to switches on windows and doors. And adding a Yocto-Light lets you take your DIY burglar alarm to a whole new level. In this How-To document we show you how to whip up an intruder alert system with a Valarm-equipped Android device, a cheap laser pen, mirror, and a Yoctopuce Yocto-Light external USB sensor.

Your Industrial IoT sensors for Tools.Valarm.net are available at Shop.Valarm.net.

1. Install Valarm Pro on your device.

Valarm is available on the Google Play store


2. Configure Valarm for the light sensor trigger. Here we’ve tested out the lumens values that the light sensor reports (use the Scan All button) and decided that if there are less than 4000 lumens (i.e., something is blocking the laser from hitting the sensor) then trigger an alert. The laser will certainly be brighter. Set the maximum lumens all the way to the max, so the laser doesn’t trigger alerts when in its normal ‘on’ mode. After we set the minimum trigger value for the lumens we set up any SMS/text message, email, or Valarm Tools web uploading responses we would like.


3. Now set up your scenario for the alert. Here we’ve used a laser pen from the dollar store, a Yocto-Light, and the mirror from an incredibly expensive outdoor navigation compass to bounce the laser beam and create a laser trip wire in the staircase. We just short-circuited the on-button in the laser pointer. For a long-term system, you’ll want a laser pointer powered by mains, or at least a bigger battery. You also might want to mount it with something better than duct tape (if there is such a thing in existence).

A chunk of duct tape and a crumpled restaurant receipt form our high-tech, infinitely adjustable mounting system.

Activated, the beam is invisible in daylight (and in darkness, though it’s really bright wherever it hits stuff – embed your mirror and sensor if you want to hide the red dots).


More duct tape, holding the universe / Yocto-Light together.


Incredibly fancy and expensive compass wasted, used just for its mirror.


4. In this case we enabled Valarm email alerts and Valarm Web Tools upload so we will receive email messages and see it on the web whenever someone trips the Valarm! Time to arm Valarm.


5. Here’s the Valarm scene in action. Intruders beware. (or be equipped with frozen CO2 and hot water to make the laser evident, and be very flexible to sneak through)

A little dry ice and hot water makes our laser trip-wire quite obvious in the dark


6. Try it out in your own scenario and let us know how it goes by sending us a message at Info@Valarm.net. Or perhaps you want to use the light sensor for your hydroponics, garden, aquaponics, or any other place to know when the lights go on or off or when the light levels go above or below your custom level.

Have a look at the Valarm blog and Industrial IoT Customer Success Stories page for more info like how to use Tools.Valarm.net for water resources management, monitoring water wells, and flood warning systems.