Ben Heck's Raspberry Pi Builds

Karen has an idea for a project, with Felix's help to create a portable Raspberry Pi photo' booth, useful for weddings and other events. This isn't only a hardware project, it also needs the linux software to help ensure we're saving the files where we want them and even upload them to an online service!

In this project the Ben Heck Team work on making the smallest Raspberry Pi Zero Portable possible. The Raspberry Pi Zero is all surface mount, with no through hole parts to desolder, so its already as small and compact as possible. Ben wires a custom keyboard with a diode in every switch to isolate buttons in a keyboard matrix. The matrix is turns a small amount of I/O into a lot of separate inputs. Felix wires the switch matrix directly to the GPIO on the Raspberry Pi Zero. By pulsing the column lines and reading the row lines he can determine what keys are being pressed. Felix uses code to make keyboard matrix readable by the I/O stream while Ben works on case design and component layout. The final build uses a NTSC screen (for compactness) with a 1000c battery charger and booster for the 3.7 volt battery.

In this project the Ben Heck team creates an all-in-one desktop oscilloscope using a Raspberry Pi, a Bitscope usb oscilloscope, and a 7" capacitive touchscreen display. Their DIY desktop oscilloscope is wired to be compact and operate as a self-contained unit. Ben designs a custom enclosure with a 3D printer and adds a black bezel around the capacitive touch screen.  To keep the unit compact they use the cable ends they have room for and manually solder the ones they don't have room for. The LCD uses a ribbon cable instead of HDMI making it easier to custom configure. Touch controls are included with the main ribbon cable connection. Their project eliminates the need to use a separate computer, connect it to the Bitscope, and then use a bnc connector to connect to standard probes.

The Ben Heck team takes a look at the Pi-Top DIY laptop kit.  Its based on the Raspberry Pi 2 and contains everything you need to make a laptop. Additionally, it includes screen, screws, battery pack, as well as a that handles the power input and does the HDMI to LVDS conversion for the LCD screen. HDMI and the LCD both use LVDS signalling but they're not inter-compatible, so there is a conversion chip. After the unboxing they set to work on assembling it. Ben preps a development board that plugs into expansion header making it easier for people to experiment on the Pi-top. The expansion charge board does not have a pin out for ports so they reverse engineer it themselves to make their own expansion port. Felix walks through adding the adafruit repository to get the AVR installed on the Pi-top.

In this project the Ben Heck team took a Raspberry Pi and turned it into a media center connected to a TV and streamed videos from a server. They use a bare bones Linux distribution ideally suited for this called OpenELEC. They burn OpenELEC to an SD Card, connect an IR sensor to a GPLO to enable the use of a remote control, configure system settings to connect to a network, and design a custom enclosure with a 3D printer. Felix walks through setting up OpenELEC using command line. Ben mounts the Raspberry Pi to a custom enclosure and installs the IR sensor onto a PCB, He solders the PCB directly onto the GPIO before adding the capacitor and the resistor.

Ben improves a Raspberry Pi MAME (Multiple Arcade Machine Emulator) Portable from an earlier project.  This time he uses a smaller and more energy efficient Raspberry Pi A+, a TFT screen for superior pixels, and adds in a built-in battery charger. He formats the SD card with "CupCade" OS and commences testing with a Raspberry Pi B+. He uses the GPIO for game control units, tests the TFT display, and connects to a battery/charge circuit.  The new power source allows you to plug the unit directly into a power outlet, allowing you to charge while playing. Ben goes over setting up the SD card, downloading a retrogame program to simulate keys pressed when certain GPIO are switched to the ground, and compiling a C program that maps the GPIO to keys. He situates the PCB and placement of switches while Felix etches a PCB.

Ben completes the Raspberry Pi MAME Portable project.  He populates the PCB Felix etched with components and finishes designing a custom enclosure. He also wires and tests the PCB to make sure it works when the Raspberry Pi, control PCB, and screen are sandwiched together in the final configuration. 3D parts are printed to for the custom enclosure before all the pieces are assembled. A test PCB is used to ensure circuits work. Ben places board components by hand. He pins down two corners of the circuit to keep it in place before flowing solder along the rest of the pins to make them stay put. He does the same for the power MOSFET and uses a little more solder than he might need for the heat sink.  He adds thru hole components such as the switches and the power connector. Wire is added for bridges or jumps between connections.

Felix uses spare parts including a TFT screen, a Raspberry Pi, and a camera module to make a point and shoot camera. Ben is asked to reduce the form factor and design a custom enclosure for it.  Felix has the camera kernel working so Ben takes it upon himself to build it mechanically and to make it as small as possible. He does this by first stripping the Raspberry Pi of components he doesn't need. He uses a desoldering iron to remove some parts and does others by hand. Felix goes over the steps he took to get the Raspberry Pi to act as point and shoot camera.  Steps include downloading the OS & preparing the SD Card; doing the initial setup of raspi-config, update, upgrade; configuring TFT, GPIO, and the camera module; installing the still camera software; and automating launch into camera mode at boot.

The team designs a Raspberry Pi based streaming web cam that uses a chat interface to control movement. Their goal is to allow people to watch what is happening online at certain times of the day or for events and to control where the camera is looking. Instead of an off-the-shelf USB web cam, with inferior throughput, the team opts for a Raspberry Pi dedicated camera module. This module offers superior performance because it connects directly to the system bus via a ribbon cable. Felix goes over the steps to make the Raspberry Pi stream video. They include installing the Raspian operating system; establishing a network connection; installing video tools: raspivid, libav, and gstreamer; getting an RTMP URL & Certificate by establishing an account on a streaming service; connecting to I2C with the Arduino; configuring the IRC bot; and streaming. Meanwhile Ben builds the mechanical features of the project. He carefully designs the project from the camera out to ensure that everything will function once it's all assembled.

This project marks Ben's first attempt to make a portable Raspberry Pi. For this build Ben uses a 512mb Raspberry Pi with Debian Linux, an LCD backup camera, a wireless keyboard to get the system up and running, game controllers to take apart and look for controls, a Lithium ion battery, and a Lithium ion battery charger. Ben uses a bench power supply to find the minimum voltage needed to run his composite LCD display. This allows him to use a switching regulator when hooking up the lithium battery to the screen.  He hooks up his battery pack to a multimeter to find the amperage draw. His Linux distribution has already been set up to autorun MAME. Ben removes all the components he does not need from the Raspberry Pi.  Ben uses a teensy development board to make controls work for the Raspberry Pi portable.

In this project Ben uses a Raspberry Pi to build a dog treat dispenser that can be remotely controlled over the web. He begins the project by building the mechanical dispenser itself. Ben makes a rotary indexer with a servo mount on the bottom and tabs that go into opto interrupters so that it can tell when its made a complete revolution. It is connected to a servo that is mounted in the first plate. Once its mechanically sound he attaches an IR interuppter so that it can tell when its done a complete revolution. The interrupter has a slot - a tab on the rotating disk fits in letting us know when its completed a 180 degree rotation. Ben uses an arduino to make sure it works.

Ben continues working on the dog treat dispenser. He gets it to work with the Raspberry Pi to enable control over the internet. He adds hardware to the Raspberry Pi to get it to the dog treat dispenser he mechanically built earlier in the project. In order to get the dogs attention whenever a treat is dispensed he uses a bright LED connected to a Tip 102 Darlington Transistor as a flasher, he searches for a servo library for the Raspberry Pi, and attaches the IR tab sensor to the general I/O of the Raspberry Pi. Ben makes a breakout board that plugs into the Raspberry Pi. The breakout board includes the wiring and the transistor. It connects the Raspberry Pi to an external 5 volt power source and also attaches to the flasher, IR sensor, and servo. Ben ports the code he wrote for Arduino to Python and programs it onto the Raspberry Pi. He compiles the code for the flash to work to get the dogs attention and a treat command to rotate out a treat.

Episode 81 - Original Air Date 17-May-2013

Ben completes the dog treat dispenser project by hooking the Raspberry Pi up to a webcam to allow remote viewer access to view images and control the dispenser. He sets up a remote SSH connection to the Raspberry Pi, hooks up a webcam to the Raspberry Pi, and sets up a web server on the Pi to serve a a simple webpage with video and two buttons. The two buttons allow the web viewer to execute code to alert the dog with a flashing light and to feed the dog by cycling out a dog treat through the dispenser. 

Ben introduces the Raspberry Pi a shortly after it is first introduced. His first Raspberry Pi project is an attempt to remain true to the creators original intent and create an educational device. His inspiration is the BBC Micro Computer from the early 80s. Like the Raspberry Pi, it was released in England and intended for education. He hearkens back to the old days of computing while taking advantage of the Pi's general purpose I/O. Ben goes over the components of the original Raspberry Pi such as the general purpose I/O, the ARM architecture, 3.3 V regulator, HDMI, composite video out, audio out, USB, and Ethernet. He designs and laser prints a case that includes compartments to store experimental stuff. The final design includes a card-edged connector and accessories to be used for the the purposes of education and experimentation. Ben reminisces about meeting the founder of Raspberry Pi, Eben Upton, at a Maker Faire.