After a few weeks of waiting, I’ve finally received two breakout boards with BMP085 barometric pressure sensors.
UPDATE (2013-01-25): I’ve updated RPi firmware today and it seems that the latest kernel (3.6.11+) includes working driver for TL-WN725N. Instructions below are now obsolete/educational 😉
I’ve decided to replace TL-WN721N adapters with something smaller. After some research and tests with my old Debian laptop, I’ve bought two TP-LINK TL-WN725N 802.11n USB adapters.
In contrast to 721’s, they are smaller and are built on different chipset – Realtek RTL8188CUS.
Installation is not as easy as with Atheros-based adapters, because no kernel driver supports this chipset. Fortunately, Realtek provides open-source Linux drivers on their website.
So, let’s get started
My Raspberries are expanded with DS3231 I2C realtime clock. It’s a very simple solution, as only required external component is a backup battery (crystal is integrated into the chip!). And it’s also claimed to be very accurate
By default, Raspbian installation uses “fake hwclock” to read previously stored date/time from file just before clock is synced by NTP client. We’re going to switch to “full” hwclock, first ensuring that our RTC is seen by kernel.
Here’s a short tutorial on how to quickly setup WiFi on your RasPi.
I’m using Atheros based TP-LINK TL-WN721N USB adapter – good and cheap.