Automation for a gas flame hardening machine
This is a seriously application using JAL. After some months this automations is working OK with good productivity: more than 400 pieces of iron in less than 2 hours every day. The principle of operation is shown here:

A 10W unipolar stepper motor drive a wheel on which are mounted 12 arc based, drop-out mechanisms. Ideally , angle between these must be 30 degrees. The small iron piece is sustained on this mechanism until a drop-out coil bump the mechanism and the piece fall into a water tank. This is happening only when the base and the top temperature of the iron piece are the same. If the top temperature of the iron piece exceed a set point A, the gas valve reduce gas to final burning flame. If the top temperature of the iron piece decrease under a set point B the gas valve open gas to final burning flame. Stepper move the wheel with 30 degrees, only after the piece was dropped in water. Some special function was added: a secure switch who test the position of drop-out mechanism and another switch who release de stepper for manually movement. The key of whole system is the pyrometer. Because the target saw by pyrometer is very small ( about 4X4 mm at base of piece and 1X2 mm at top of piece) this can be positioned at maxim 10 cm distance from flame, were is very hot. A cooled device, Peltier based, keep pyrometer sensors at 15 Celsius degrees. Gas valve is driven by a DC reducing gear using a BA6209 forward / reverse controller (manufactured by Rohm). Here is the source:  automat.jal
And here you can see the schematics:
 

Pyrometer schematics is not shown here, however if someone is interested mail me. The principle of operation for pyrometer is photoelectric conversion of light using a pair of photodiodes in same package. The photoelectric current is converted in logic signal using a differential amplifier and a group of comparators.

Interfacing 2 IO lines of PIC with 4 buttons and 7 different functions

This idea comes in my mind trying to developed an industrial control unit with PIC16F877 for an industrial microwave oven (5 kW continuous wave magnetron). Because the IO capabilities of  PIC are limited from my application and no encoders like 74147 or 74148 satisfied me I think a clever(?) solution which I never saw anywhere else:

The table from above picture describe exactly the principle of operation: IO pins can be outputs (with HI or LOW state ) or inputs. Choosing a convenient configuration only one of the buttons state are read at once by the program. Example : for B3 read, IO2 must be input ( HI state when B3 is released and low state when b3 is pressed) and IO1 must be HI to ensure polarization for Q2. Notice that schematics can be applied even if interrupts on keystroke must be used (Rb4 to Rb7). R2 and R3 must be used to protect IO pins for unknown state in prototyping phase (when can be inserted in socket a PIC with IO1 in low state and IO2 in high state or vice versa).
Reading buttons are done by next program: 4button.jal