IdaCam - A Raspberry Pi Zero W camera

This project is inspired by the Becca Cam (by Becca Farsace @ The Verge) to create an interchangable lens camera using the Rasberry Pi Zero W and the Raspberry Pi High Quality Camera module.

The Name

The name comes as my daughter's name (exactly like Becca's Becca Cam). The pronunciation of her name is IPA: "ıːðɑː" and the pronunciation of cam is exactly as it's written.

Background/Motivation

My wife is a photographer (a great one), and my daughter has been seeing a DSLR her whole life. She's even got a tiny canon toy camera with a detachable lens, using which she re-enacts her mother's photo shoots.

Given her fascination with protography, I wanted to give her an interchangable lens camera, but either they were too heavy for her or too expensive to give her or both. I looked around for a lot of toy options, and nothing really hit the spot. Looking at constucting a camera gave me the option of the Lomography Konstructor series, but they're film cameras which is a problem again.

I had been experimenting with a Pi Z 1.3 (not a W) and found it to be very useful, and easy to use. Then, when I came across Becca's article (and associated Youtube video), I thought it was just the perfect thing to make for her. The price for all parts was within USD 150, and the weight was well within her holding capacity.

This is now the way to create an interchangable lens camera from scratch for my daughter while showing her the internals of a camera and educating her about Making.

Hardware Requirements

• A Raspberry Pi Zero W. I got mine via redirect to a official distributor from the Pi website. The price was reasonable.
• Screen - Waveshare 32b for the RasPi
• Power - Xiaomi mibank pro - The only power bank I found that doesn't reset it's output ports on charging curcuit getting connected, AND I had it lying around. Plus more expensive to get Ras Pi Power management addons here in India.
• Camera Module - Raspberry Pi High Quality Camera
• Lens - Official Raspberry Pi 6 mm Wide Angle Lens for Pi High Quality Camera - USD 31.59
• Camera Cable - Official Raspberry Pi Zero V1.3 Camera Cable USD 1.5
• Buttons - SeeedStudio Grove Yellow Button -2xYellow and 1xRed and Grove 4pin to female jumper cables - 1 USD each for all.
• Jumper Cables(Thank you, Dupont), Female to Female, and Female to Male.
• 2.54 mm standard pitch male headers (correct terminology via Digikey):
  • one of 2 x 20, or
  • 2 of 1x20 (they'll come as a strip of 1x40) (Thank you for these, Stuart)
• MicroSD card - Samsung EVO Plus 32 GB
• 90 Degree USB converter
• Zip ties
• CP2102 USB to TTL UART serial converter
• Soldering Iron, Solder and YouTube.

Development Log

Hardware setup process

• Collect all the Hardware requirements
• Solder the headers to the Raspberry Pi Zero W. I found that using a bread board or an ATA connector to hold the pins and tying the Zero W against the pin holder using the end holes (which coincidentally line up perfectly with the header holes) allows for a well positioned set of pins. (TODO: add PIC)
• Connect the SPI LCD module to the Zero W. (TODO: more details)
• Realise no SD or OS
• Write out the RasPi OS lite image to the SD and boot it.
• Realise that there are no accessible terminals
• Disconnect screen to connect serial adapter to UART and enable console logging to it (last cons entry in kernel cmdline is used for boot logging) - stupid 20-pin female connector on the screen
• Use Male to Female dupont jumpers to connect screen and the Zero W, taking into account the Serial UART and I2C and other NC marked lines of the screen
• Connect LED buttons
• Realize that too many different connectors need 5V and GND as compared to available pins
• Solder 2 rows of pins on a prototype board and short each row together to connect to 5V and GND to create a power expansion board
• Connect 5V and GND connectors of all buttons and the screen to the power board board, and the board to the Zero W
• Connect the RTC to I2C pins and power board
• Connect the the camera module to the Zero W via the camera connector using the camera ribbon cable
• Connect a microUSB cable to the powerbank, and see that the connector extends out too much
• Get an L Shaped 90 Degree Right Angle USB Converter to decrease length
• Figure out that this doesn't help as now the width is too much.
• Strip the sheathing of the Converter, and use a hot air blower (thanks to the wife) to melt the hot glue of the 90 Degree converter to "convert" it into a U shaped converter.
• Attach a Mi MicroUSB to USB-C converter to the powerbank to make charging port accessible to the box wall
• Get a Laser cut box of the dimensions such that all the components fit into the box with careful placement (TODO: Add the laser cutting files from the person who did it for me and add it here.)
• Drill holes to expose the buttons and to attach all parts using screws/zip ties.
• Attach the USB UART converter to the serial port of the W Zero.
• Put in the parts into place with zip ties and hot glue, because no screws (or screwup with the screw precurement).
• Profit.

Software

TL;DR; section

• Sanitized command history
• Full command history of the working IdaCam
• Full command history of the first failed attempt at the system
• Supplimentary command history of user root of the first failed attempt at the system
• See the references section for approximate software development log

Pre-boot Software setup

• Download the Raspberry Pi OS Lite from the Rasberry Pi website and install it on a Micro SD card for the Pi Zero W.
• Mount the boot partition and
  • Enable SPI in the config.txt
  • Enable I2C in the config.txt
  • Enable the camera port in the config.txt (TODO: Give snippet)
  • Add the screen overlay to the config.txt (TODO: Give snippet)
  • Add the kernel command line params to the cmdline.txt (TODO: Give snippet)
• Mount the root FS partition and
  • add wifi configurations and priorities to etc/wpa_supplicant/wpa_supplicant.conf. (TODO: Give Details)
  • enable ssh service via systemd linking. (TODO: Give Details)
• Connect the UART to a USB port of a linux system and start up screen on the port.
• Put in the SD card and boot up the Zero W. Monitor the DHCP server to ensure that the the Zero W gets an IP address.

Post boot setup

Get into the Pi Zero W and do the following:

• Install the following packages:

  • xserver-xorg-video-fbturbo # display
  • xserver-xorg-input-evdev # Input from touch sensor, I think
  • xinput-calibrator # Calibration of input
  • xinit
  • vim, git and cmake
  • python3-picamera
  • Optional:
    • screen (this is more convenience than requirement)

• Make and install fbcp:

  • git clone the repo https://github.com/tasanakorn/rpi-fbcp/
  • set up build with cmake
  • build it with make
  • Install fbcp into /usr/local/bin/ (my preference, use any path dir based on yours)

• Set up framebuffer initialization in /etc/rc.local

  • ``

• Add configuration for fbturbo

• Add condifuration for evdev

• Enable terminal auto-login for user pi

• Add configuration for .session to start xterm -ls screen

• Add conditional startx into ~pi/.bashrc

TODO

TODO

• Add scripts to automate actions
• Investigate direct SPI display usage instead of HDMI display mirroring.
• Better cable routing
• Upgrade to CM4 with 4GB RAM + 8GB eMMC on a custom IO carrier board
• Better design of the the Laser Cut box

Extras - The IdaCardboardCam

In an effort to get her to understand the concept of focusing the image with a manual focus lens, I decided to build her a small cardboard camera, using co-axially aligned cylinders(like a telescope), but using the lens from an old dysfunctional point-and-shoot 35mm film camera that my mum had lying around.

We took it apart, showing her all the different parts, like the shutter, the flash, and other parts of it, to extract the lens. The lens was a molded 3-lens assembly which screwed onto the camera body, and was fixed with a bit of glue once it was focussing the light at the correct place (where the current frame of the film spool would be).

The outer cylinder had the lens affixed to it's front, and the inner cylinder had a translucent plastic sheet (cut to the size of a single 35 mm film frame) as the focus point for the image as captured by the lens. I added an insert into the outer cylinder to disallow the inner cylinder from collapsing into the outer completely and damaging the focus point/moving the lens out of alignment.

Pictures as below:

License

Everything here is released under the HIRE ME/PAY ME License (a modified 2 Clause BSD License). Please see the LICENSE file for details.

References:

• Google Fu(A BIG THANKS to the Google folks and Siva(HOD CSE IITB 2004))

• Interactive Raspberry Pi Pinout

• Waveshare LCD support repo - WARNING: Doesn't work out of the box.

• Grove LED Button Schematic

• Random Button and LED tutorial for the RPi

• Raspberry Pi Camera Documentation

• Picamera Getting Started

• WaveShare 3.2inch RPi LCD (B)

• RTC time with systemd on a Pi

• Raspicam commands and raspistill --help

• Displaying an image on linux without running X

• Open An Image on Host While SSH'ed?

• WaveShare Tutorial: External Button

• A solution to the question use ssh to control tty1

• fauxcon - the Solution to controlling the gallery via buttons

• subprocess.Popen

• python signal defs

• practical example of python subprocess control

• Controlling Pi Zero W swap size limit

• man fbi on the Raspberry Pi OS command line interface.