Submitted by drew on

The popular clock module is uses the DS1307 real time clock chip, which is not very precise. For just a few dollars more, you can get a module with a much more precise DS3231 RTC chip. The one I got was SunFounder's module from Amazon for $9 (free shipping for Prime). It plugs right onto the Raspberry Pi's 40 pin header and doesn't even interfere with the plastic case I have. I have a Model B, but this module should also work on Model A and Model B+. The instructions refer to DS1307, but the chips use the same I2C commands, so it also works for DS3231. I changed some references that appear in 'standard' instruction from ds1307 to ds3231, but you could instead leave them as ds1307 just as well.

To install the module, run the following commands (from SunFounder's instructions). Turns out Amazon's product page also has good comments and perhaps more up-to-date than SunFounder's.

# Comment out the blacklist entry so the module can be loaded on boot 
sudo sed -i 's/blacklist i2c-bcm2708/#blacklist i2c-bcm2708/' /etc/modprobe.d/raspi-blacklist.conf
# Load the module now
sudo modprobe i2c-bcm2708
# Notify Linux of the Dallas RTC device (use -0 for Model A or -1 for Model B)
echo ds3231 0x68 | sudo tee /sys/class/i2c-adapter/i2c-1/new_device
# Test whether Linux can see our RTC module.
sudo hwclock

You should see a response with what the chip thinks is the date. I think mine said 1999 or some such. No problem.

If your system date is NOT correct (if you don't have an internet connection or something), set the date using ONE of the following commands, with the appropriate date and time, of course:

# Only do ONE of two the below:
sudo dpkg-reconfigure tzdata
sudo date -s "Sep 27 2014 12:46:00"
# Now that your system date is correct, simply use this command to transfer the system date to the chip:
sudo hwclock -w

 

Next, to read the time from the RTC chip and set the system time from it at every boot, open /etc/rc.local and add these two lines above the exit 0 line:

echo ds3231 0x68 > /sys/class/i2c-adapter/i2c-1/new_device
hwclock -s

We can also disable the ntp daemon and fake-hwclock during boot. 

sudo update-rc.d ntp disable
sudo update-rc.d fake-hwclock disable

That's it. Pretty easy.

 

You can still sync the system time from the internet using...

sudo ntpd -gq
sudo hwclock -w

 

Tags
Raspberry Pi

Installing GBridge on Windows 8, Windows 8.1 and Windows 10

Submitted by drew on

 

Just because I don't want to have to look this up again. Windows 8's driver signing enforcement prevents installing GBridge's network drivers. I posted how to work around that on gbridge.net forums when I was testing the Windows 8 preview, but their forum is offline now.

Windows 8

This method works for Professional or Home versions.

Grape Harvest

Submitted by drew on

 

I finally got a full harvest off of this vine (before birds, etc.) These grapes are pretty sour, if you just pick and eat. And seedy. However, I always thought they might make good jelly or something. So this year, I have lots of grapes to try something.

Basically, the process is:

Raspberry-Vanilla Pudding

Submitted by drew on

We have a picnic on July 4 where we are supposed to bring a dish. An hour before the picnic... what should we bring? We have lots of fresh-picked raspberries and that vanilla pudding I got last week. After a few minutes of Google-searching for things that use those two ingredients (no results, except for baked items and stuff of the wrong kind), I am going to make my own recipe for this.

Five Crunch Mix

Submitted by drew on
 
Five different textures of crunch for a delightful and versatile snack that doesn't leave your taste buds feeling like you drank an ocean of saltwater.
 
Shake together in a container (or snack bag) in the desired proportions....
  • honey nut cheerios
  • pretzels (thin style, broken in pieces)
  • unsalted peanuts
  • Spanish peanuts
  • banana chips
  • raisins
 
I usually go heavy on the cheerios.