Frost Sheridan Returns a Kodak MegaPlus Camera to Service with a Teensy 4.1-Powered Frame-Grabber
Custom add-on turns what was once $40,000-worth of lab equipment into a low-resolution "pocket" camera.
Maker Frost Sheridan has brought a Kodak MegaPlus 4.2i digital camera from the 1980s back to life, building a custom Teensy 4.1-powered frame-grabber to create a low-resolution yet surprisingly high-quality boxy portable camera.
"The MegaPlus series of cameras were originally produced by Kodak starting in 1986 as the first >1 megapixel digital cameras available on the market, and due to their extremely high price tag (as much as $40k!) they were only intended for scientific and industrial use," Sheridan explains. "These cameras have zero controls, indicators, displays, or storage of their own, so they must be connected to a computer that's equipped with a compatible frame grabber card in order to be used."
Initially, Sheridan and friend — the owner of the camera in question — had thought the device communicated with the frame-grabber, which neither of them had, over SCSI. Sadly, the SCSI-like connector turned out to carry highly-proprietary signalling. With no desire to hunt down an original frame-grabber, which would leave the camera tethered and suitable for indoor use only, Sheridan decided to build a new one using a Teensy 4.1 microcontroller.
"The high speed of the MegaPlus's parallel image transfer (10MHz * 10bpp = 100Mbps) means that I'll need a pretty fast microcontroller to fully capture the image," Sheridan explains of the choice of microcontroller. "The Teensy 4.1 also features expandable RAM (a necessity for this project as each image produced by the camera is 4MB and the Teensy “only” has 1MB of onboard RAM) and a built-in microSD card slot (convenient for storing captured photos), so it's the perfect choice for this application."
An initial proof-of-concept saw bare wires run between a breadboard and the back of the camera, with control instructions sent from a separate system over an RS232 link. The parallel image capture system, meanwhile, drops the lower two of the 10 returned bits: "I'm throwing away a bit of potential dynamic range," Sheridan admits, "but I would much rather work with nicely byte-aligned 8-bit words instead of trying to wrestle weird awful 10-bit words, so I'm totally fine with the trade-off."
In addition to the Teensy 4.1, the portable frame-grabber includes an 8MB PSRAM chip to buffer the 4MB images returned by the camera, a 5V regulator so the grabber and the camera can share a 24V power supply, and a hacked-apart SCSI cable for wiring, with a display doubling as a viewfinder and buttons for control on the top of the 3D-printed case.
"All of the electronics are installed on a hand-wired protoboard 'PCB,"" Sheridan adds. "Like I always do with my protoboards, I used 30AWG wire-wrap wire to route all the connections on the underside of the board, sorta like PCB traces."
More details, including samples shots from the camera, are available in Sheridan's write-up.