Raspberry Pi serial communication

Since I was tinkering with Pi network settings, sometimes I was loosing SSH connectivity.
Annoying process of hooking Pi to display and keyboard forced me to look for a serial connection option. This way I will just have to switch between two terminal windows, instead of messing with the cables.
I've got a dongle named "USB 2.0 to TTL Uart 5-Pin CP2102 Module Serial Converter", based on reviews it should work in this configuration.

Raspberry Pi with RT5370 Wireless Adapter

My PI worked flawlessly for some time hooked up to ethernet, but I wanted to move it away from router, and for this I bought some noname wifi dongle. After hooking it up, I run lsusb and it showed up as:

ID 148f:5370 Ralink Technology, Corp. RT5370 Wireless Adapter

Google told me that it should work out of the box. I used vanilla configuration:

/etc/network/interfaces

auto lo
iface lo inet loopback
iface eth0 inet dhcp
allow-hotplug wlan0
iface wlan0 inet manual
        wpa-roam /etc/wpa_supplicant/wpa_supplicant.conf
iface default inet dhcp

/etc/wpa_supplicant/wpa_supplicant.conf

ctrl_interface=/var/run/wpa_supplicant
update_config=1
network={
        ssid="MYSSID"
        scan_ssid=1
        mode=0
        proto=WPA2
        auth_alg=OPEN
        pairwise=CCMP
        group=CCMP
        key_mgmt=WPA-PSK
        psk="MYPASSWORD"
}

The system behaved weirdly, it worked for some time with very sluggish connection speed, but most of the times, ssh connections where just timing out. People complaining about unstable performance, where told to hook it through powered USB hub, since it is possible that power supply on Raspberry cannot produce enough power.

Wireless mouse autopsy

My Logitech wireless mouse (m510) stopped working, and I took it apart.
I damaged it during disassembly, and still don't know what was wrong with it, but here are some fun facts so far.

It uses two AA batteries, but they are connected in parallel, so operating voltage is 1.5V.

Unifying receiver technology supports up to 6 devices.
Mouse MCU is nRF24LE1.
MCU datasheet describes "MultiCeiver" technology, which (surprise!) implements six parallel data pipes.

This awesome picture was taken with a phone and magnifying glass. 

Who needs a microscope when you have a phone with camera :)

You can notice that some capacitors are missing (c25,c24,c18), but it seems they have never been there.

This part of PCB is actually very close to the datasheet (Figure 78. nRF24LE1 OTP, 5×5 mm QFN32 schematics). C22,C23 are C1,C2 in schematics, C17,C18,C11,C12 are C3,C4,C5,C6, and C4 is missing in schematics as well.