This thermostat with ATTiny25 Atmel microcontroller would only allow the fridge to go up to a maximum of 5 degrees… hardly an ideal beer brewing temperature.
Source:aliask

The servo testers which can be found in shops are quite expensive and the shematics published here and there do not achieve the requested precision. Most of the time they are based on the famous NE555 timer IC and are limited to one function.
The use of a PIC (here 16F84 or 16F628) gives the opportunity [...]

This project DoorBell was created by Quozl . He used microcontroller PIC 16F84.
A microcontroller driven doorbell circuit with features:
one second instant pulse output,
one second delayed pulse output,
two minute lighting output,
latching has been triggered indicator,
processor alive indicator,
ignore additional trigger for preset duration.
Source: Quozl

Rickard have designed the hardware of the PIC video game system to be able to run several different kinds of games. It has two standard C64/Amiga/Atari joysticks and video and audio output. The processor is a PIC16F84 running at 12MHz and generates both video (PAL and NTSC) and audio in software.  The hardware design is [...]

This circuit is used to control a total of three independent processes:

Generating video signal
Revenue characters from the keyboard, decoding and sending to the serial line
Revenue characters from the serial line and store into memory for display

Source: Pandatron

Universal tester of semiconductor components with detection and simple control detects an unknown component and its basic parameters.
Currently supports the following devices: Transistors type NPN, PNP, N-MOS, PE-MOS, ND-MOS, PD-MOS, N-JFET and P-JFET.
Source:Pandatron

The following construction has just two features ideal for basic testing and troubleshooting on audio devices.
Here low-frequency generator of structure / trackers offers the following uses: In function generator allows the injection of low-frequency signals in the way of audio devices such as amplifiers.Contrast,in low-frequency trackers feature allows you to listen to any low-frequency audio [...]

This device is fully functional sound card for PC. The main advantage of using PCM2704 against PCM2702 is much easier construction. The circuit can be powered directly from USB port.
Source: diy4fun

This is a very simple and easy to build programmer for Atmel microcontrollers from AVR family. The microcontrollers must support serial programming. This programmer is connected to a PC through the RS232 serial interface and can be used with the PonyProg or Avrdude software programmer.
Source: diy4fun

Yet another darkroom timer using a PIC 16F84A. All the functions are in firmware:

Lamp(s) light at start of timing and turn off when timer reaches zero.
A set of leds were added between the minute and second leds which blink during timer operation.

7 segment displays include tails for digits 6 and 9.
[...]