picopy

Copy sd cards to to a hard drive on Raspberry Pi-based Swallow devices

Using Swallows to copy SD cards

Swallows are raspberry pi-based devices that copy SD card content to a hard drive. This document explains how to use Swallows to copy SD card content to a hard drive. It assumes the Swallows are fully set up, so that picopy.py runs on boot. See this document for instructions on setting up Swallows.

The Swallow always has a “status” which indicates the current mode of operation. The LEDs indicate the current status of the Swallow. The flow chart may be all you need to understand how to use Swallows. (Just make sure your destination drive has a file or folder named PICOPY_DESTINATION, and don’t disconnect drives without ejecting them first!)

LEDs:

Status (green): reports the current status

Progress (blue): during copying, reports the progress out of 10 based on the total size of the transfer. For instance, if the transfer is between 10 and 20% complete by size, the light blinks 2 times in a row every ~4 seconds.

Error (red): this light blinks to report errors (See Errors and Troubleshooting below)

Source (white): this light is on when a source drive (such as an SD card) is mounted.

Dest (white): this light is on when a destination drive is mounted. A destination drive is any USB drive with a file or folder named PICOPY_DESTINATION in its root directory.

Shutting down the device

If the Swallow has been configured using this document, turning the device off requires you to hold the power button for 3 seconds. If any external drives are mounted, the device will not shut down, instead it will blink the error LED 10 times rapidly. If the device is shutting down successfully, it will blink the Status, Progress, and Error LEDs together 5 times slowly. Wait at least 15 seconds before unplugging the power cable.

Buttons:

There are four buttons and two types of button presses: a tap (<1 sec) and a hold (1-3 sec)

Go: used to prepare and start transfers

Stop: used to interrupt copying tasks

Eject: used to eject (unmount) drives. A tap ejects src drive, a hold ejects dest drive.

Power: power on and off the pi (this will immediately cancel any copying task!)

Detailed Instructions

Set-Up

1. If you are using a new “destination” hard drive (the hard drive to which you will copy data): Plug the “destination drive” into a computer. In the top-level directory of that drive, make a folder called PICOPY_DESTINATION. This is not where the data will be copied to, its presence simply signals to the Swallow that this drive should be used as a destination rather than source for data copying.

2. attach the Swallow and hard drive to their power supplies

3. attach source (SD card) and destination drives to the USB 3 (Blue) ports

4. check that drives are mounted (src and dest LEDs light up)

Copy Files

The flow chart above shows how each of the buttons can be used depending on the current status.

The typical workflow without interruptions or errors is:

1. Tap “Go” to prepare a transfer

• Checks if source and destination are available
• status changes from “idle” to “ready to copy”

2. Tap “Go” again to start the transfer

• Status changes from “ready to copy” to “copying”
• wait for it to finish (blue LED indicates progress as # flashes/10)
• Status changes from “copying” to “checking copy”
• Status changes from “checking copy” to “complete”

3. Tap “Go” again to acknowledge the completed transfer

After copying

1. Eject the source (tap eject button) and destination (hold eject button) drives

• The src and dest LEDs should turn off
• It is now safe to unplug the drives from USB ports

2. If desired, power off the device by holding the power button for 3 seconds

Errors and Troubleshooting

Steady red light: incomplete transfer

This means the data was not completely transferred to the destination; the rsync process failed to finish or was interrupted Hold the Go button to acknowledge the incomplete transfer and return to “idle”

3-blink error: source drive

• Check that the src LED is on. If it is not, no source drive is mounted (or multiple possible source drives are mounted). (A source drive is any external USB drive that does not have a file or folder named PICOPY_DESTINATION in its root folder)
• Make sure there aren’t multiple source drives mounted
• Unmount then unplug all USB devices and start over
• Power off the pi and start over

4-blink error: dest drive

• Check that the dest LED is on. If it is not, no destination drive is mounted. (A destination drive is any external USB drive that has a file or folder named PICOPY_DESTINATION in its root folder)
• Make sure there aren’t multiple destination drives mounted
• Unmount then unplug all USB devices and start over
• Power off the pi and start over

5-blink error: insf space

• There is not enough space on the destination for the contents of the source. Use a destination drive with more space
• If you believe there should be enough space, check for large .Trashes and remove the trash if desired

6-blink error: bad files on source drive

• Unable to access source drive and read disk space. Likely caused by corrupted files on drive.
• Recommended to inspect source drive and, if desired, copy accessible files between drives manually through the terminal or on another device.

10 rapid blinks of red Error LED:

• User attempted to shut down the swallow, but there are external drives mounted. Shutdown will not occur. Unmount all drives before shutting down.

Blue, Green, and Red LEDs flash 5 times slowly together:

• The device is shutting down

General debugging:

• ssh into the raspberry pi from a computer
• Open the log files located in /usr/bin/picopy.out to read the output of the copying script

schematic for Pi-HAT

SSH into pi with Ethernet cable

If you connect an ethernet cable directly to a Raspberry Pi, you can SSH in (provided SSH is enabled, ssh file exists in ~) with:

ssh [email protected]

for instance,

ssh [email protected] for unchanged hostname, or

ssh [email protected] if the hostname was changed to swallow-001

This allows you to view, manipulate, and debug files and programs on the Swallow.