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Greeting to all, i have a mega2560( NOT AN ADK ), and usb host shield 2.0, and the following a) 1 pendrive( 8GB) formatted as fat32 b) 1 300GB usb hard drive formatted as fat32 c) 1 1TB usb hard drive also formatted as fat32 i know, there is a limit on fat32 that the maximum drive/partition size must be 32GB, and i have found a disk utility that can format such big drive as fat32( if you want to know what it is, please ask) after formatting all these drives( a)+b)+c) ), i have created folders+files on them, no access problem when using them in linux, mac, win?; so i have wrote a sketch in arduino and was successful in create+write to the pendrive, but when i use the identical sketch to write to the other two drives, the sketch died at usb init; all these were using the same+identical arduino+usb host shield 2.0, and the operation of the hard drive( one at a time ) was power with external adapter, after b) and c) failed, again i used the same pendrive, and wrote successfully; then i reformatted those two large drives as fat32(this time both with size 30GB)...again failed at usb init;

any advice/suggestion would be greatly appreciated , thanks for reading and STAY HEALTHY !!!

surv
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  • I have no direct experience with that, but using a drive as big as 300GB or 1TB seems rather off limits with an Arduino. For what do you ever need that much space with a small and slow AVR Arduino? – chrisl Oct 12 '20 at 21:06
  • thanks for your comment, what you have said about the size is TRUE+CORRECT, the 300GB and the 1TB was just laying around, and i wanted to test out the limits, since i have 5 sensors in a robot, and by each write size is 100bytes and over 720 minutes...you get the picture... – surv Oct 12 '20 at 21:10
  • Ok, that sparks the question how often you read per minute. To fill up 300GB in 720 minutes you would need to write the sensor data for all 5 sensors every 72us. I think the writing itself will take way way longer than that. With the 30GB from the stick you are still at a rate of every 720us. I mean, I don't want to invalidate your question, since it is a good question. Just wondering about the closeness to reality here. – chrisl Oct 12 '20 at 21:47
  • the 300gb was just laying around, i used it to test out 00) this fat32 will work on drive/partition larger than 32gb, 01) the test i did with 5 sensors, for 3 hours each sensor took 1GB...so for 5 sensors over 12 hours that would be 20gb+(???) and if i run those sensors in a 24 hours that will go over the fat32 limit of 32gb – surv Oct 12 '20 at 22:27
  • You are dealing with an MCU without an OS, if you want to have a hard disk, get a Raspberry Pi which run Linux with proper hardware driver. 2) Do you really need to read the sensor that frequent? I don't know your application, normally if you need that kind of data, you would process the data immediately rather than storing it in storage for later to process, I would suggest to understand the concept of edge computing if you need to process such intensive data acquisition.
    • – hcheung Oct 13 '20 at 01:17
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    thanks to all, yes i do understand my case is a mcu without an os, and yes, i have considered among raspberry pi( 3+4), and udoo, udoo is the only one that has a leonardo mounted...but with very limited digital+pwm capable pins, so without exception, ALL operates on 3v, and all my sensors operate( meaning giving feedback to arduino ) at 5v...as to why am i collecting this amount of data, that is an assumption on your part, in worse case scenario, as i have stated can be over 40GB, since it worked with a 8GB pendrive, next i will try with a 64gb pendrive, – surv Oct 13 '20 at 16:04
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    if that works, then pcb inside these usb hard drives are over 8 years old...thus speed ,any comment would be appreciated, thanks again – surv Oct 13 '20 at 16:05
  • ok, folks, i am sure i have this solved, after i used 2 64GB pendrives, 1 is with usb 3.0, 1 with 2,0... the 1 with a 2.0 worked and the one with 3.0 did not...and i found out that i was attaching those hard drives to the usb host shield 2.0 with a usb 3.0 adapter...so consider this closed – surv Oct 15 '20 at 02:45