Introduction: StreetSpeak.SF

StreetSpeak is a mobile, storytelling platform that allows people to tell and hear brief stories in response to an interchangeable prompt originally prototyped by Restart [your city] for the Market Street Prototype Festival in San Francisco, CA.

StreetSpeak encourages passersby to become engaged with others in the built environment they share, and connects them to others in their community. The interactive design allows individuals to activate the spaces where they live by contributing their own experiences to expand the reach of the platform.

StreetSpeak can be used by people of all ages and abilities to record responses and offer opinions, tapping into the diverse needs of each community. Restart [your city] hopes to use StreetSpeak as a way to help build better cities with the input of the people who live there.

Step 1: Gather the Tech

Using the folowing electronics you can build a system to record and play short videos with a Raspberry Pi. We made a system that could be powered by either an outlet or a large USB power supply.

    Raspberry Pi 3 The Raspberry Pi has some trouble recording video and audio simultaneously, but it offers flexibility in screen selection, speaker output and input devices. We ended up spending less than we would have on an iPad and a developer license even with purchase of spare parts and electronics we did not use.

    MicroSD Card With the newest version of Raspbian installed

    Raspberry Pi Camera with connector ribbon and plastic housing to mount it

    Raspberry Pi 7" Touch Screen from Element 14. We ended up using a touch screen to build our UI, this one worked and survived three days of use by strangers. We also bought a spare in case this was damaged.

    We used two different microphone solutions with USB ADCs(One of them didn't survive the installation and the other provided decent but not excellent sound quality)

    VALinks Mini Flexible Plug and Play Home Studio was our self contained option. It plugs directly into the USB ports and provides excellent durability and decent sound quality.

    Pyle Professional Convergance Microphone (With a Lexicon Alpha 2-Channel desktop Recording Studio) allows for more flexibility in the setup and live tuning of the sound input to prevent clipping and preserve dynamic range. This sounded better, but we broke the microphone so the above fallback was great to have.

    HDMI Dongle with analog audio output

    Battery Powered Speaker With line audio in that can be connected to the above HDMI Dongle. (This is important because the audio DAC built into the Raspberry Pi is fairly noisy, and OMXPlayer is currently incompatible with USB audio output.

    2 USB Keys which we used to store videos made by the users of the installation

    USB keyboard So our users could enter contact information

    USB cables to power everything

      Step 2: Set Up Supporting Software on the Raspberry Pi

      You can use the touchscreen and keyboard to install the following software packages on the Raspberry Pi

      • Kivy is a nice app framework that let us make graphical apps and command the Raspberry Pi
      • FFMPEG let us combine the audio and video recordings to make a "talkie"
      • Alsa This audio package lets us use the USB audio devices

      Then test all the hardware individually using arecord and omxplayer, you'll probably have to do some work to ensure the interfaces for each piece of hardware is properly set up.

      You can also turn on SSH access for the machine so you can manage it externally over wifi and modify the keyboard mappings so the app cannot be interrupted.

      Step 3: Build the Python App

        Using Kivy, OMXPlayer and the Raspberry Pi Camera, We created a Python app to allow users to record and view short (60-90 second) stories. USB thumb drives let us store the recordings and review them to make the set of videos that users would see if they asked to hear a story.

        Step 4: Get Supplies for the Enclosure


        • Plywood
        • Polygal
        • Metal pipes & corner connectors
        • Window curtain
        • Zipties
        • LED lights
        • Nuts
        • Washers
        • Long screws


        • [1] Drill
        • [1] Handheld electric saw
        • [2] Standard wrench
        • [1] Screwdriver
        • [1] Allan wrench

        Step 5: Build the Enclosure

        ** need photos of the plan-- we can take screenshots of doc from emily maybe?***

        Build the external cube structure out of metal piping.

        • Cut all Polygal and plywood to the required panel sizes
        • Using the metal "sliding" attachments as a guide, drill through the plywood panels and attach using the long screws, knuts and washers. The plywood will act as the back of the enclosure and provide stability.
        • Repeat this process with the Polygal panels
        • Secure Polygal panels to one another by drilling holes and using zip-ties.

        Step 6: Connect All the Tech

        Using the schematic diagram above, connect:

        -power cable to pi

        -the pi to the touch screen

        -the two USBs containing the app and videos to the pi

        -the microphone assembly (desktop recording studio to directional microphone)

        -the speaker (via the USB audio adaptor + two sided headphone jack)

        -the keyboard

        The screen is connected to share power with the raspberry pi on the 5v Line and over USB. The keyboard, Microphone (or ADC) and a USB storage device to the USB ports of the raspberry pi. The camera is connected and all the audio is connected. The speaker, and the screen are powered by an outlet (the speaker has a battery so it doesn't need to be connected at all times.

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          3 years ago

          What a great idea! Beautifully made!