• Category Archives electronics
• ## Blody HDDs

im sure some of you noticed the server went down quite often in the last month first I downgraded the system to 12.04 LTS in the process I backed up my home folders in a .tar.gz this was my first problem NEVER use tar.gz on critical backups use tar.bz if you need the tarball compressed. Any way I just threw the the tarballs on my older media HDD and when I tried to decompress it it kept getting stuck and when I tried to pull them off the server it would get stuck or transfer very slowly at times and at others it would be at full network speed. Turns out the HDD was not too happy and I knew the drive was throwing up the occasional S.M.A.R.T errors but the drive decided to start having corrupt sectors after I migrated. I recovered as much data as I could but I lost a lot of data including a full user profile and all of the emails stored on it and that had more than a few critical info emails so yeah bad luck on the timing.

• ## I need a bit of help

so I got my Atmel xmega-B1 Xplained demo board last week and through the course of the week I have been trying to test it but all I can do with it is play with the pre-programmed stuff on the board because my computers don’t want to recognize the board properly, and unfortunately I don’t have a JTAG programer to do any software testing or even see the debugging info.

The board only shows up as a generic HMI device when according to the documentation it should automatically show up as an Atmel HMI, a mass storage device, and as a COM port. So far I have tried the demo software installed various drivers that I found on Atmel’s website (windows wont let me use any of them) and even Atmel studio 6 does not want to recognize its existence so if any one has a suggestion please let me know
I don’t exactly want to do a review of something I cant properly test I would buy a JTAG programmer but I don’t have the money for it right now

maybe in a few months but not soon

• ## Server Down time

the server will be down this afternoon for about 45 min to 1 hour starting at about 6pm EST

The last few weeks I have been having server stability issues and kept seeing disk read errors in the logs I initially thought it was a failing hard drive which I then sourced to a faulty SATA cable but that wasn’t the only issue. Fortunately the hard drive is in good health and was working properly when I tested in my desktop but I still kept getting disk read errors I finally sourced it to the drives not getting enough current to run properly when I went to confirm this theory by checking the PSU voltage in the BIOS it was fluctuating between 4.8V and 5.01V so yeh the power supply is on its last leg. once I discovered that I removed all non essential components from the PSU and disabled 2 of the CPU cores which has kept the system running for the last 4 days   I have ordered a new one which came in today and will be replaced tonight.

UPDATE:

server has its new PSU and has happy voltages across the board and is much quieter than it was before

UPDATE 2:

I just realized i forgot to publish this last night DERP

• ## Power down, phone dead? Not a problem.

Since most people don’t own a backup generator (including myself though I would like one). I have been in this situation a few times in the last year  due to a new building going up in my area or fires  or wind between the power generation facility and the city and have lost power for more than a few hours.

In the longest lasting one I found that my phones battery was pretty close to dead so I pulled out the bread board to remedy that problem my first reaction was to use a lm7805 (datasheet) a 5V regulator  that would have been nice but I didn’t have any at the time (the closest electronics store is a 20 min bike ride away (and there POS terminals would probably be dead anyway) so I couldn’t be bothered but I had a few dozen lm317t’s (datasheet)  a variable regulator

With the last of my phones battery I  looked up the data sheet (if I had room I would probably keep a print out of all the components data sheets  I own )  and built the circuit with the light from the camera flash

The equation for the voltage regulator  is  Vout = 1.25v*(1+r2/r1)

I used a 240 ohm resistor for my r1 so 1.25(r2/240)  and I want a near 5v out put. So 5v=  ((5/1.25) -1) *240=720 and the nearest resistor I have is 750. So 1.25(1+(720/240)) =5.156 close enough! the devices internal regulator can handle an extra 160 mV. In any case its a CMOS logic device so its all 3.3V anyway. I ended up using 2 in parallel to dissipate excess heat (I didn’t have any TO-92 sized heat sinks).

As for a final product I added some low value caps (.1 uf on the input and a 10 uf on the out put) along with some protection diodes (see final schematic) . I now have it soldered on a perf-board and in an Altoids tin  for use in the future. In fact the last time I went camping I brought it with me  and it came in handy. The first night there  pretty much killed the battery due to the cold night granted the only use I have for my phone was emergency communication and as a time piece (not an issue any more with my pebble).

(please note that the pin numbers are wrong out is pin 2 and adj is 3)

(please note that the pin numbers are wrong out is pin 2 and adj is 3)