OOKLONE: a cheap RF 433.92MHz OOK frame cloner

Fabien Le Mentec August 12, 20149 comments

A few weeks ago, I bought a set of cheap wireless outlets and reimplemented the protocol for further inclusion in a domotics platform. I wrote a post about it here:


Following that, I had access to another outlet from a different vendor:


The device documentation...

Practical protection against dust and water (i.e. IP protection)

Dr Cagri Tanriover July 5, 2014

Recently, I was faced with a challenge to provide IP65 compliance in a product that had to have humidity and pressure sensors on it. The tricky part was to keep the cost of the unit under $15 while meeting this requirement.

Under normal circumstances, one can put all the electronics within an IP65 enclosure that is affordable and readily available off-the-shelf most of the time such as the ones shown in this link. However, given the humidity and the pressure sensor need to be exposed to the...

A wireless door monitor based on the BANO framework

Fabien Le Mentec June 10, 20145 comments

I have been thinking for a while about a system to monitor the states of my flat and my garage doors from a remote place. Functionnaly, I wanted to monitor the state of my doors from a remote place. A typical situation is when I leave for holidays, but it can also be useful from the work office. To do so, I would centralize the information on a server connected on the Internet that I could query using a web browser. The server itself would be located in the appartement, where there is an Internet connection.

The major issue I had is that the garage is located 7...

Using the Beaglebone PRU to achieve realtime at low cost

Fabien Le Mentec April 25, 20144 comments

I work as an engineer in a synchrotron facility. A few weeks ago, I helped the people in charge of the power supply developments to integrate a realtime control algorithm on a prototype platform: a BeagleBone Black (BBB) running Linux. I had already worked with this board in the past, and I found it very interesting given its excellent resources versus price ratio (around 40 euros). This time, I was impressed by its realtime capabilities. I thought it would be a good idea to share my experience here.

In this application, the control loop core algorithm looks as...

A simple working I2C (TWI) level shifter

Dr Cagri Tanriover July 16, 20132 comments

Recently, I had to interface two hardware platforms via an I2C bus (a.k.a. two-wire interface, TWI) to query temperature and real-time clock information. This task is relatively straightforward on the software side. However, because the power supply of the two platforms were different (one at 3.3V and the other at 5V), the I2C busses could not be connected to one another directly and a level shifter was required between them.

 There are commercially available I2C level shifters such as TI’s PCA9515BDGKR that is affordable but what do you do if you do not have such...

Requirements, Specifications and Tests

June 20, 2013

As a freelance developer of all things embedded, it's important that right through a project everyone involved knows what is expected, who is responsible for delivering, and how to confirm that what is delivered meets the customers expectations.

I have a tried and trusted method that works for me each time, is flexible enough to deal with feature-creep and solid enough to give the client that warm fuzzy fealing that they crave.

I've dound that this method of working has in the past been the thing that swings a contract in my direction, above the competition. And in fear...

Layout recomendations and tips for best performance against EMC

Maykel Alonso January 4, 2013

When making the layout of the circuit diagram, it is interesting to perform a preliminary analysis of several issues in order to minimize problems arising from electromagnetic compatibility.The analysis consists in:

Identify / Analyze components: This section will analyze the integrated components, as well as any recommendations it may have the manufacturer. We must also analyze the...

First Steps in OrCAD 16 [Capture]

Maykel Alonso June 1, 20126 comments

Hello community, I know that in last posts I have been writting about the Software. But what about Hardware? In last months I have been dealing with it, exactly with OrCAD 16. And I will explain how to build a PCB  in 2 articles. For begginers could be a good and easy guide.

This article explains the part for the designing of the schematic, and in the next one which i will explain the layout part.

The first stuff you must known about OrCAD is that it is not an unique tool for hardware designing as PCAD. OrCAD it is a suite for multiple tools. Here you have the...

Using XML to describe embedded devices (and speak to them)

Martin Strubel October 12, 20111 comment

This article discusses one of the typical development cycles in embedded device and communication design and presents a possible, light weight solution using the free DClib/netpp framework.

The challenge

Assume we're faced with the design of an embedded device, be it a simple SoC unit or a more complex, uC controlled engine with various attached peripherals. From first prototype to the market, the following development cycle is typically walked through:

Design hardware, choose peripherals, I/O, define...

Deeply embedded design example - Logic replacement

Gene Breniman July 9, 2011

I have always believed that some of the low-cost, low-pin count, low-resource microprocessors would make an excellent choice for the replacement of discrete logic components.  In these cases the deeply embedded microprocessor would become less of a general purpose computer and more of a logic replacement, providing a prescribed function with no connection to the outside world.  In a world of bigger, faster and more expensive, it is a pleasant change of pace to embrace the smaller and cheaper, and build a slightly better mousetrap. The following is an...