by w2aew @ youtube.com:
This video shows a simple circuit that can be used to control the position of an typical remote control (RC) style servo with an analog voltage. The PWM (pulse width modulated) control signal format for an RC servo is reviewed, followed by the presentation of a simple circuit that can be used to control the servo with a simple adjustable DC voltage. The circuit is built with rail-to-rail op amps and a few resistors and capacitors. Note that the schematic presented doesn’t include all of the decoupling on the power supply and reference lines that you would likely want to include. A description of the circuit, as well as a more in depth discussion of each of the building blocks such as an integrator, hysteresis comparator and DC signal conditioner circuit including an attenuator, inverting amplifier and level shifter, is presented.
Circuit Fun: Control an RC Servo with an adjustable DC voltage - [Link]
by Michael Whybray:
Most desk fans I have come across have three speeds: Full Speed, Almost Full Speed, and Off – useless if you want just a gentle air movement, and far too noisy if you are trying to get to sleep (in your bedroom of course, not at your work desk!). The squirrel cage induction motors they use have switches to two or more windings – and possibly a capacitor – to reduce the drive current. But unless the drive frequency is also reduced, the torque and speed stability are poor, so minimal speed reduction is usually available on these fans. Using a triac to provide phase control of the voltage works poorly for the same reason, with the speed very sensitive to the triac firing phase angle and fan load, and has a tendency to stall.
Sleep easy with this desk fan speed reducer - [Link]
Ioannis Kedros @ embeddedday.com:
Why this long intro? Well, I am an engineer, a maker in general, that wants to build stuffs. And the swags above came in a nice cardboard tube. A very strong, thick, with a nice light plastic type coating (helping with the moisture during shipping).
This makes a good indoor enclosure, but with proper treatment will be a nice fit for an outdoor enclosure as well. I am going to put a Raspberry Pi inside it together with a camera and some sensors for reading environmental variables.
The RPi is the Model B and has some connectors around it that I am not going to use. Those are taking space and placing the Pi slightly offset of what I want. I decided to remove them and use some of those in future projects. Nothing is going to the trash bin! Anyway, I am not going to use this Pi to somewhere else. The project will be placed permanently in my “lab” and I will do only software improvements.
Project Tube - [Link]
First ever affordable 5axis multi-fabricator that brings most advanced fabrication right to your desk:
We’ve designed machine that combines multi- fabrication methods: 5axis milling being one of them. 5AXISMAKER is a machine versatile enough to fabricate most advanced design prototypes in readily available material while on your desktop right next to you.
Being an alumni of Architectural Association we’ve had an access to most advanced fabrication tools in the world. Yet there is no desktop prototyping machine that has versatility to replicate this technology.
Our company has been initially found as design and fabrication practise, and after years of working with wide range of designers from different fields it has become clear that one should have an instant access to a pallet of prototyping tools. We wanted same machine to include a set of tools like CNC mill, touch-probe, 3d printer, wire-cutter and have a potential for further add-ons.
5AXISMAKER: First ever affordable 5axis multi-fabricator - [Link]
by JColvin91 @ instructables.com:
Whether we care to admit it or not, motors can be found all over in our everyday lives; they just tend to be hidden. Motors are present in cars, printers, computers, washing machines, electric razors, and much more.
However, there are a number of people (which until recently included myself) that would be uncertain of how to make a motor run if they were handed one. So, let’s learn something today. Let’s learn how to use a stepper motor!
How to use a Stepper Motor - [Link]
An instructables on motor controllers for cheap robots by JayWeeks
Almost every robot needs to power a motor of some sort or another. Problem is that motors take quite a lot of power, compared to what most microcontrollers operate with. To solve this problem, robots use what is called a motor controller, which usually amounts to some form of electronic switch that can turn on a very high voltage, using a very low one. That’s what we’ll be making today!
Motor controllers for cheap robots - [Link]
A magnetic stirrer uses a rotating magnetic field to mix fluid samples, such as buffers and media for growing bacteria. Since only a small magnet bar has to be put inside the sample/fluid, the risk of contamination is minimized. For protein purification, overnight sample dialysis steps often utilize magnetic stirrers.
Below are beta release DIY instructions for a magnetic stirrer this summer, courtesy of Malcolm Watts and Massey University in New Zealand. The stirrer runs of off a battery and has multiple speed settings.
You can also download the pdf: magnetic_stirrer_betarelease_V01
Magnetic Stirrer - [Link]
Trandi blogged about his RC servo and stepper motor project. He writes:
For those interested in reproducing this example:
The board is called “EP2C5 Mini Board” and has a EP2C5T144C8 Cyclone II FPGA on it
I used a standard, 9grams micro RC Servo
I used a 28BYJ-48 stepper motor and it’s driver (you can purchase these as a bundle for very cheap on dealextreme or banggood)
I used the free edition of Quartus II from Altera, version 13.0 SP 1 (be careful, later versions do not support Cyclone II FPGAs anymore)
I created a simple project, pasted all this code as a single module (it would of course be cleaner to separate the RC Servo and stepper control code into independent modules)
made the “Top level entity” in the General configuration page equal to “counter” (the name of my module)
used the Pin Planner to assign the inputs/outputs as follows:
FPGA : RC Servo and Stepper motor control in Verilog - [Link]
Conventional electric motors rely on the forces of electro magnetism to provide motion. An item in the UW-Madison news letter announced that a motor is under development at the headquarters of C-Motive Technologies which uses the force of electric fields.
According to Dan Ludois, an assistant professor of electrical and computer engineering at the UW and co-founder of C-Motive Technologies “We have proven the concept of a new motor that uses electric fields rather than magnetic fields to transform electricity into a rotary force, the distinction may sound minor, but it could solve a number of practical problems while saving money”
An Electrostatic Motor - [Link]
Ondřej Karas of DoItWireless writes:
We described simple method, how to drive modellers servo. Today, we are going to try to drive this servo from potentiometer connected to TR module ADC. It is reaction to forum thread where is discussion about airplane model control possibility.
Wireless servo controller II - [Link]