Retrieving data recorded during robot operation

[grosssj]

1. Reliable externally attached SD Card for V5 brain
2. Method or driver for accessing card data through USB port while connected to controller or brain

I have had reliability issues trying to enable my students to record information during a robot operation for analysis. Using a microSD card in the provided slot, does work, but has issues with physically accessing the slot and fragility of the media and the slot for repeated insertion/removal.

I have been trying to use SD cards connected to the V5 brain via microSD(male) to SD(female) extenders.

This is to allow a larger form factor less likely to be lost or damaged by student handling also reduce the wear on the V5 brain’s internal SD card socket.

I have tried this using different brands of both cable-based extenders and printed circuit board based extenders without finding a set of cards and extenders that work reliably with the V5 brain.

I receive either constant or intermittent errors iwhen accessing the SD card. depending on the combination of adapter and SD card types.

I am hoping that you are aware of a reliable configuration of extender (cable type preferred) and SD card type for connection (through the extender) to the MicroSD slot of the V5 brain. I prefer SanDisk SD cards, if they are in the universe of cards that perform well.

I have seen the following issues:
Unreliable capture of the extender’s male connection (microSD) in the Vex V5 brain’s push-in-push-out SD socket. Does not lock in place during the insert operation.
Unreliable signaling through the extender between the SD card and the brain’s microSD connector. This gives either complete failure or intermittent errors when accessing the card.

Please identify products (combinations) that work reliably in the data logging application. I am currently unable to get reliable operation of the data logging feature that would enable the students to characterize the operation of the robot and apply optimizations to their designs.

I am currently recording data to a memory array during robot operation and then attempting to transfer the data to a file on a card at the conclusion of the robot operations. The data collection utilizes a separate thread to avoid problems with IO delays during writing data to the card from interfering with data collection and robot operations. The writing to card is deferred until after data collection and robot operations have concluded. The data collection thread samples the timer and several sensor values which it places in an array in memory and waits for sample period. This repeats until the robot finishes its activity and then the data then written from the data array to the card.

An alternative, and in some ways superior alternative to supporting easy card removal would be a host utility or device driver that allowed files on the card while in the brain to be accessed and manipulated by the computer attached through the USB port connection to the brain or to the controller.

Thank you for your attention to these matters. I look forward to your insights on how to handle this issue.

Best regards,

Steve Gross
Robotics teacher / coach
The Harker School

[iseau395]

I don’t know if this is what you want, but you can print to the console to skip the SD card and get data straight to the computer

Using the Print Console in VEXcode V5

This article uses blocks but it works in every vex programming environment. The data rate is slower then writing to a file if the data is sent wirelessly through the controller, but it is a lot more convenient then using an SD card.

[some.person]

If you want, you could use websocket if you are using VScode as that can wirelessly send whatever appears in the print console if you connect the controller to the brain. VScode Websocket Server - #6 by Creation