discussion / Camera Traps  / 2 October 2022

Multi-SD card reading hubs

Hi everyone,

I'm writing to see if anyone has any experience with using/building hubs that can read multiple SD cards at once? I'm trying to explore ways to speed up the manual transfer process of camera trap images from the SD cards to hard drives. With the teams I work with, we often have 50+ camera traps  to download data off. Having the potential to read multiple cards at once could potentially really speed up the manual transfer, particulary when there is a need to utilise the cards again in a short timefrime.

There are some commercially available models like the SanDisk Pro-dock 4, or Lexar Professional Workflow series (both with 4 SD card slots), and I recall reading a while back about a project that had built their own and paired it with a download script program that processed the photo metadata (it was on Github but alas I can't find it again despite searching). Most basic SD card readers are for users that may only be working with one or a few cards at once so it makes sense to only require limited read capacity, but for many of us that work with 10s of cards at a time from large camera trap arrays, I thought this could be a helpful advance. 

Interested to hear if anyone has worked with a system like this, or knew whether it was possible to design one?

Hi Jamie--

I've only ever used one of the commercial models (I forget if it was SanDisk or Lexar), and it worked fine--each card showed up as a separate drive in Windows, and I was mostly manually dragging and dropping files until they were set up in the staging directories I expected before automation could take over.

It could also be possible to rather than using an off-the-shelf multireader, instead use a USB hub (on whatever is the fastest USB standard your computer will support) and then getting a bunch of individual SD card readers to plug into that. Even then, it's not clear what the bottleneck will be in terms of reading data off cards, writing it locally, writing it to a NAS, etc. Would still likely require separate automation on the software end of things but could be more flexible

If you have a PC with USB3.0 ports, you can actually get really fast (theoretical) transfer rates and just hang a bunch of readers off of them. And if you have a desktop with fast PCI-e slots, you can use PCI-e to multi USB-3 port adapters to expand and scale. You may need to have a beefy PC to handle fast transfer speeds depending on how much is offloaded by the hardware though. 


I have been using a 12-card Lexar Professional Workflow system for several years to process images from 24 trail cameras.  The system has 4 bays, with 3 card readers per bay.  I wrote software to automatically download and rename the images using metadata read from the info banner burned into the images by the camera.  (Alternatively, the software can use the Exif metadata attached to the image.)  The software is described in a recent Wildlife Society Bulletin: 

The software is available on github:  

Don't be put off by "time-lapse recordings" - it works on still images also.


Mike Hilton

Have a look at @tessa_rhinehart 's TechTutors on scaling up acoustic surveys. This is addressed at 11 min: 

The "hexadecapus" is the hardware, but transfer is automated by naming the SDCards prior to use and scripts take care of the transfer. The scripts may be written up in the audiomoth guide but the kitzes lab have this on github (although it may be mac specific)