Voltage Controlled PWM Generator

Giorgos Lazaridis writes:

From time to time, i have use many circuits that generates PWM pulses. Most of them will translate a resistor value into duty cycle change. Although that is handy and easy, sometimes a voltage controlled PWM generator is needed. There are of course those micro-controllers that could make almost any kind of PWM signal translation, but i preferred to study and create a circuit without the use of such chips. I tried to keep it as easy as can be, but without this reflecting to the accuracy and integrity of the output pulses.

Voltage Controlled PWM Generator  - [Link]

DIY Battery Pack holder with dual voltage outputs

Giorgos Lazaridis writes:

This project is only to give you a new idea. I upload such projects from time to time, because i know that sharing simple solutions and ideas is more useful than sharing a complete and complex project.
The problem that i had, is that i wanted a battery holder that will hold 4 AA batteries in one series. I will use this pack for my door key-code lock project. I need to have 4 batteries inside the door, so space is critical. I cannot have the typical 4-pack battery holder, because it is too thick to fit inside the door. So this is what i've done:

DIY Battery Pack holder with dual voltage outputs - [Link]