An old but interesting app note (PDF) from Microsemi on resistorless current-sensing technique. [via]
This application note introduces a simple current-sense technique that eliminates that sense resistor, resulting in system-cost reduction, PCB space saving, and power efficiency improvement. Furthermore, the new current sensing mechanism allows higher dynamic tripping current than the static one (built-in low-pass filtering) to improve current-sense noise immunity.
A simple current-sense technique eliminating a sense resistor - [Link]
Here’s a DIY 38mm x 38mm laser engraver build using CD-ROM/writer on ATmega328p by Davide Gironi:
A laser engraving machine, is a tool that uses lasers to engrave an object.
To build this tool I’ve used two old CD-ROM writer that lays around in my garage.
The X/Y positioning system it is build using the CD-ROM motor assembly. For the engraving laser i use the CD-ROM writer laser.
With this hardware the engraving area are will be almost 38mm x 38mm.
A DIY laser engraver build using DVD and CD-ROM/writer - [Link]
Pulse oximetry is a non-invasive method for monitoring if a patient’s oxygenation is unstable and Arduino user die_Diode sent us his version of a DIY Pulsoximter developed with two Arduino:
Arduino Mega for the oximetry electronics and Arduino Uno for the graph. The electronics includes LED Driver, Photo current transformation, patient-dependent calibration LED, Active filters, Nellcor SpO2 sensor. Adafruit OLED displays Vitalparamter. Noritake VFD display GUU-100 shows the PPG. The boards are connected to the electronics with a Protoshield.
DIY Pulsoximeter developed with two Arduino - [Link]
kurtscottage @ youtube.com writes:
In this video I’m showing you how I built some solar panels from start to finish I tried to make it as detailed as possible. These panels cost me very little to build and are fun projects for everyone. This is just one way of doing this there are lot’s of others doing this and good videos out there. Presently I’m using my panels at a job site where there is no electricity available they are running my RV off the grid. These panels are not encapsulated but they work well and low cost not for on roof installation best to be close to ground for inspection.
Homemade Solar Panels Diy tutorial - [Link]
The award winning EAGLE is a powerful and flexible PCB design software offering high level functionality of expensive commercial circuit board design software at a fraction of the cost for over 20 years. EAGLE offers the three modules: Schematic-Editor, Layout Editor and Autorouter embedded on one single interface. EAGLE is easy to learn, easy to use and easy to buy. It runs on Linux, Mac and Windows and allows feature enhancement, such as simulation, 3D-visualization, data import and export and self defined commands, through User Language Programs (ULP’s) which are partly integrated in EAGLE and available at the download area.
EAGLE Version 7 is released! - [Link]
IQRF meets demands of developers and smaller companies and brings possibility to develop wireless applications without programming and with minimum initial costs.
IQRF Alliance and an advantage of usage of Direct Peripheral Access – DPA and hardware profiles were introduced to you in our article IQRF Alliance brings wireless networks without programming. By entering to an IQRF Alliance the user gains access to a full DPA functionality, what greatly simplifies development and usage of IQRF wireless modules. DPA ensures compatibility of all products using this protocol and thanks to this it´s possible to add functionality of wireless communication into your product within few days or weeks.
However if you don´t suppose so fast deployment of your product and a 1000 Euro credit/ year is uselessly too expensive for you, now you have a possibility to use DPA and hardware profiles even without entry into the IQRF Alliance. The only thing you need is to develop with modules marked with „DC“ prefix (data controlled), i.e. for example DCTR-52 … Various IQRF modules are available in two versions – standard, as well as „DC“. If you´re a member of IQRF Alliance, standard modules are the right ones for you (without marking „DC“). If you´re not a member of an IQRF Alliance but despite this you wish to use significant simplification of development in a form of DPA and hardware profiles, then the “DC” modules are ideal for you. For a slightly higher price you have a chance to develop and use wireless communication and control with a maximum simplification. It is beneficial to use “DC” modules up to approx. 400 pcs/year. Then it´s already more advantageous to become a member of IQRF Alliance.
IQRF technology features, description of a new development environment IDE and OS, as well as advantages of IQRF Alliance membership advantages can be seen in a record from our webinar Wireless MESH networks without programming.
Creating of wireless MESH networks now even more effective - [Link]
Making your own PCB boards for DIY electronics projects is not difficult. Doing so as a DIY project is extremely handy and allows almost anyone to custom design one-off, or small batch circuit layouts relatively quickly and cheaply, without the need for the volumes or costs involved in using the services of professional circuit board manufacturers. With care, DIY PCB project results are usually of extremely high quality and are very satisfying. Even more interest can be added to projects when printed circuit boards are combined with CNC cutter designs for shaping of the circuit boards.
There are various different methods for making PCB boards. Each method has various pros and cons, with most considerations being linked to cost, quality of finished product, accuracy required for fine circuits and availability of chemicals and materials.
DIY Etching of Printed Circuit Boards (PCB) - [Link]
Everytime we need to test a stepper motor controller we have to connect it to the parallel port of the computer or to a function generator to obtain the necessary pulses the realize the movements of the stepper.
This is a quicker method to check a controller integrity. Simply to make the life easier here is a square wave signals generator. A potentiometer or a trimmer regulates the pulse generation of the 12F675 microchip (a square wave, between 20 hz and 3khz). Ok, there are thousands of different ways to create a pulse generator, but we had a lot of microcontrollers.
12F675 pulse generator - [Link]
by Henrik’s Blog @ hforsten.com:
Ionizing radiation is something that almost anyone finds exciting (or scary) and I’ve also been for long wanted to build a Geiger counter. Unfortunately Geiger tubes have usually been too expensive to seriously consider buying them just for a hobby project. But I found out that sovtube sold soviet cold war era Geiger tubes only for a couple dollars. I bought one CI-22BG tube and one CI-3BG tube for total of 16€ including shipping from Ukraine to Finland. The site itself didn’t really convince me payment via Paypal failed because of invalid seller email address and gmail warned me that order confirmation e-mail might not have come from the address it claimed. However, I got both of the tubes and they seemed to be okay.
DIY Geiger counter - [Link]
An application note from Texas Instruments, A single-supply Op-Amp circuit collection (PDF!):
There have been many excellent collections of op-amp circuits in the past, but all of them focus exclusively on split-supply circuits. Many times, the designer who has to operate a circuit from a single supply does not know how to do the conversion.
Single-supply operation requires a little more care than split-supply circuits. The designer should read and understand this introductory material.
A single-supply Op-Amp circuit collection - [Link]