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A simple Radio Frequency Transmitter. The circuit includes a DC rejection capacitor, input low pas filter, and a resonant circuit for AM modulation. A tunable capacitor is used in order to generate a resonating carrier.
This design is made with reference to a design in Practical Electronics for Inventors, Third Edition

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This AC dimmer circuit utilizes a zero crossing detector and Triac. The output power can be controlled by adjusting a potentiometer value. The max current allowed is 10A (limited by the Triac).

This device can control the power delivered to any type of AC device, not just lamps. It can work on AC motors, heaters, power supplies,etc.

I've noticed that the circuit mill in development is having issues with small adjustments (0.3 mm). During small movements, the axis will do one of two things - it will either not move at all, or it will move too far. For example in the picture below, the left pattern was done keeping the Z axis at a steady height. The right pattern was done with the Z axis adjusting to keep the cut level. As you can see, the mill appears to be "slipping" over time, and the bit cuts further and further into the board.

No Z movement (left) vs Level compensation (right)

Here's a fun video showing all of the work that went in to prototyping, testing, and manufacturing television sets in the 1950's.

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This circuit is capable of generating a constant 13V from an input from a solar panel of 5V-17V (or more). There is also an extra 5V output for logic circuits (IE some sort of embedded control system). Design components and parameters were found using the Boost Converter - Component Calculator.

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A simple 8 channel denounce circuit board. Wire your buttons (or relays) to a positive voltage, and bring them (along with a ground reference). The output of the board will be a nice clean transition from high to low (and vice versa)

The filtering circuit is a first order low pass filter that operates on the equation:


Where $f_c$ is your desired cutoff frequency in Hz. A handy sage mathematics script was written to easily calculate and experiment with values for the 1st order filter: Low Drop Out Regulators vs. Buck Converters

In this video the energy efficiencies of Low Drop Out (LDO) regulators and Buck converters is discussed. A quick graph is generated in Sage Mathematics to compare the two circuits power consumption

When designing any microcontroller (uC) based system, I find it can be a good idea to first plan out what signals are going to go to which pin on a the uC. Sitting down and filling out a document like the one pictured above can be a very efficient way to organize your thoughts and rap your head around your design. Your allocation document will also help when routing your schematic, PCB, when you are writing software, and when you are debugging. This document can be very valuable and is often overlooked!

A pin allocation planner for the Atmega32A

Currently the OCI standard is to use QUCS as a simulation environment, and KiCAD as a design environment. However wouldn't it be nice if everything could all be done with a single tool? Well that may be a possibility worth exploring. The CERN group has put some work into integrating SPICE into KiCAD. Just check out the video below!

Jay Carlson on his site has compiled an extremely comparative report of a wide range of 21 microcontrollers that are less than $1 USD. Selecting microcontrollers can be a daunting task and this acts as a great reference. Check out his work below!


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