#lm311

Couple of months back we decided to create our own media server to store our MP3s and digital photographs. But it gets postpone several months due to unavailability of main-boards and other resources. Finally, after reviewing several prototypes we decided to build our media server using Banana Pi (BPI) and MiniDLNA. Before finalize BPI we checked several main-boards which including Raspberry Pi B+, Orange Pi One and BeagleBone Black. Out of all above main-boards we choose BPI M1 because of its inbuilt SATA2.0 interface, Gigabit Ethernet port and availability in local market.

As an operating system we use Bananian Linux, which is Debian derivative for BPI platform. To sore all our content, we use Seagate 1TB SATA 3.5 inch hard disk drive. Bananian OS and other packages are loaded into 8GB SD card. To power both BPI and SATA disk drive we design PSU using LM2576-5.0 step-down switching regulator IC. Also during the prototyping stages, we notice that both hard disk drive and BPI A20 CPU get heat-up during the long runs and to cool those components we decided to build simple fan controller with temperature monitor. After couple of designs we finally build BPI support board with above 5V regulator and LM311 based fan controller. To make it simple we construct above two components in 80mm × 53mm single side PCB.

LM311 - Differential Comparator IC

2pm jlab, worked on building the filters. Wasn't working out well when I was using the LM311 and so I switched to the 741's and it seemed to be working fine, except the 3dB frequency seems to be off, possibly due to the tolerances of the resistors and capacitors.

6pm operating systems, some questions about the assignment, then task/context-switching, scheduling, sleeping processes (interruptable/non-interruptable sleeps), implementations of linked lists in the kernel, looked at some more kernel code related to those