Back Removed – Experimental Engineering

Posted on July 12, 2011 by The Engineer — Leave a comment

Sigma Mini Keychain LCD Photoframe

This is a cheap Sigma branded keychain photoframe. User buttons for power & selecting photos are on the left.
There are two white LEDs on the bottom edge that function as a torch as well.

Front of the unit removed, showing the LCD module. The USB jack is bottom left, next to the pair of white LEDs & above that is the 32kHz watch crystal that the CPU uses for timekeeping.

Here the back has been removed showing the 3.7v Li-Ion cell used to provide power.

Here the display has been removed from the PCB exposing the chipset.

Here the CPU blob-top chip & a flash memory IC are visible. The CPU is a Sitronix ST2205U.

Posted on February 28, 2011February 10, 2011 by The Engineer — Leave a comment

Sanyo Talkbook VAS

Here is a Sanyo tape recorder, with built in voice activation. Takes standard audio cassettes.
Here visible is the speaker on the left, microphone is on the right of the tape window. The tape counter is at the top.

Back cover removed from the unit, showing the PCB & the connections. The IC is the controller/amplifier.

Top of the PCB, control switches, volume potentiometer & microphone/headphone sockets on the right. DC power jack top left. Switch bottom centre senses what mode the tape drive is in.

Rear of the tape deck, main drive motor is bottom right, driving the capstan through a drive belt. This drives the tape spools through a series of gears & clutches. Belt going to top left drives the tape counter.

Front of the tape drive. Read/write head is top centre. Blue head is bulk erase head used during recording.

Main speaker. 8Ω 0.25W.

Simple mechanical tape counter.