Public Lab is an open community which collaboratively develops accessible, open source, Do-It-Yourself technologies for investigating local environmental health and justice issues.
This page describes how to set up a camera to repeatedly/continuously take pictures during [balloon or kite mapping](/wiki/balloon-mapping).
**Lead image by @mathew depicting the recommended method: [holding the shutter button down with a knotted string under rubber bands](https://publiclab.org/notes/mathew/1-29-2012/using-knot-trigger-cameras)**.
For timing two cameras together, see [dual camera triggering](/wiki/dual-camera-trigger)
## How do you keep the camera continuously shooting photos during flight?
Many cameras can be set in "**continuous shooting mode**", which generally allows you to hold down the trigger button to take many continuous photos. This means you can use the simple "Knot and rubber band" method, [listed below](#Activities).
Note that continuous mode is different for each camera, and not all cameras have it. [Check the camera selection page](/wiki/camera-selection). We recommend Canon cameras for reliability; some cameras will shut off after a few minutes. See below for details.
Taking lots of photos is generally easier than controlling when a photo is taken. Once you find a camera with continuous shot, test the battery to see how long it will shoot. Put in a memory card with 4gb+. Consider getting a second battery.
Some cameras can be set programmatically, such as Canons using the [Canon Hack Development Kit (CHDK)](http://chdk.wikia.com/wiki/CHDK), and CDHK can be triggered via the camera's [USB port](/wiki/dual-camera-trigger). Some Canons can also also be triggered by infrared remote control codes, useful for stereo or near infrared camera pairs, along with [Stereo DataMaker](http://stereo.jpn.org/eng/sdm/index.htm).
[Cris Benton and others use motors to trigger cameras that can't be programmed](https://www.flickr.com/photos/kap_cris/3154193529/). A more drastic option is to hack a timer directly into the camera's shutter button circuit, [like this 555 timer](http://publiclaboratory.org/notes/mathew/8-5-2011/adjustable-555-based-shutter-trigger-circuit).
Although the ["knot and rubber band" technique](https://publiclab.org/notes/mathew/1-29-2012/using-knot-trigger-cameras) is easiest, here is a collection of guides to different ways to trigger a camera. Add your own!
## Timelapse Apps
There are also many smartphone apps for taking timelapse (including [Sky Camera](https://publiclab.org/wiki/sky-camera), by Public Lab contributor @mercyorangi). Let's collect notes and guides on using these on a unique page, and using the #timelapse-apps tag: