Prototype for Project Echo

In Engineering Bodies of War, ITP

For my Engineering Bodies of War final, I built a “behavioral”  prototype for a low-tech radio based communication device meant to facilitate communicating threat levels between parents and children. These devices could be helpful in rural settings (i.e. remote villages in Africa) where there is no support for more modern communication devices or even in developed countries as a cheap alternative for communicating one’s safety.



Project Echo is intended to be a system a handheld devices that allows very basic communication via radio waves. To briefly describe the product, each member of your family would have a hand held device that has 4 settings:


  • Blue – “Are you OK?” – this question would be answered by one of the 3 threat level states.
  • Green – The person is safe.
  • Orange – The person is in a dangerous situation but is presently safe.
  • Red – The person is in danger.

Each setting is accompanied by a unique sound and visual pattern relevant to it’s meaning to make it easily discernible for the user. I would imagine a parent could ask the child if they were okay using the blue setting and the child would respond using the appropriate threat level. Check out the video below for a look at the behavior of each setting.



I didn’t get to the fabrication stages, however, here is a sketch below that illustrates the type of interface I am envisioning. It would be very simple and would have a visual indicator (RGB LED), a dial to let the user select the threat level, a “Send” button to send the selected threat level to a loved one and a “Receive” button that kills the transmission once the recipient has heard the message. Lastly, there would be a series of small LED indicators to signal who the message was from, as this is intended for a whole family to use and each family member would have their own specific LED marker.


While there are presupposed meanings for each of the 4 settings, I imagine there being two labels on the back of the device below the speaker that allow families to ascribe their own specific meanings to each setting and clearly label who is associated to each little LED marker. One of the suggestions from our class was to give people the option to send a signal with the noise turned off for situations where you might want to alert your loved ones discretely. While programmatically that is very easy, I’d like to think about how to intelligently add that feature into the interface because an additional lever or switch might not be user friendly in high stress situations.




Unfortunately with the tight timeline, I was not able to get the radio communication to where it needed to be. I got to the point where I was able to get my circuit to communicate using SoftwareSerial via an Xbee to another Xbee connected to my computer, however, the SoftwareSerial was interfering with the sine wave I was using to manipulate the sound and visuals for settings 3 and 4. Therefore, if I wanted to demo the circuit with radio, it would result in weird behaviors for settings 3 and 4. Just to show you the radio communication I was able to establish, below you’ll see the alertLevel variable on the terminal connected to the recipient Xbee as I selected setting 3 on the dial of my circuit connected to the other Xbee.


Screen Shot 2015-03-20 at 3.16.02 PM


For the next iteration, I would like to focus on getting the radio comms working properly. The first step would be to set up communications between my Arduino circuit and my computer using radio and then I would move on to working with two separate Arduino circuits. The next item is to figure out is how to best integrate the silencer option so someone can signal without the volume. Then, I would add the receive button and the logic to kill the transmission if the button were pressed. Lastly, I would solder the circuit to a PCB and execute V1 of the enclosure.








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