I2C Geiger Counter

With nuke plants operating under questionable technical safety, natural events threatening humans and their dangerous energy production artifacts, and other humans disseminating fear through nuclear sovereignty upon the rest of the world, we came a long way from the happy ignorance of distant decades.

Baby monitor

While preparing to be a father for the first time, I have found most baby products to be more expensive than would otherwise be desirable, given its ephemeral usefulness. Considering the full blown economical crisis that we face today, spending copious ammounts of money in things that soon become useless, seems a little too light headed and perhaps irresponsible.

AMIRO - more enhancements.

After a few months of posting abstinence here are some fresh new things to show this summer. The android application has been dramatically improved with new features and better visual layout. Additionally a portable video screen have been build, in this case sporting a 4.3" tft panel, a 1.2 GHz analog video receiver (originally used in a fixed manner), a LiPo battery, and a custom made battery voltage warning circuit (yes, LiPo batteries are particularly susceptible to damage under deep discharge situations).

Controlling Amiro (the name I have baptized the car) from an Android phone (HTC Desire)

While the Java PC application is useful for testing and controlling the robotic car while sitting in a chair, for on the field fun a more practical solution had to adopted. So using a popular platform that Android is, I decided to port the (Java Swing) application I already had, to run on any Android phone with a accelerometers and a Wifi connection. As the car behaves like an access point, all it is necessary is to associate the phone to it, and run the application.

Just about as fun as it is to drive it, coding the client in Android was quick an fun experience.
The interface had to contain just the essential elements. While the target hardware has abundant resolution (480x800), like in any mobile platform, screen real estate is always a concern. As such I had to economize on the components to be displayed. The result was a relatively simple UI:

Merry Christmas

Christmas is a great time for parents and kids to experience engineering with the inspiring cheerfulness of eating turkey, cakes, and looking at the fireplace while it's snowing outside. Offering the right gifts is a good way of bringing up the excitement that building artifacts can cause. While, of course, not all infants have the same thirst for scientific knowledge, for those which we find to have potential, the choice of technical gifts is not to be disregarded. While in my personal view, reminding myself as a toddler brings the memories of how vibrant and exciting it was to receive a chemistry kit, a microscope, an electronic device ready to be disassembled, etc, in the mind of a modern kid this might not be quite so satisfying. A Gormiti castle, a bunch of Ben Ten toys or any other sounding brands will certainly trigger more "processes" in a toddler's cognition.

A discussion about how today's television and toy industry affects children and youths is of little impact, but it is a fact that it is now in the hands of the parents and educators, to control the degree of exposure of their offspring to these elements, as the sole regulating factor seems to be profit generation alone.

Like with many other aspects of our world, let's hope some sense will grow out in the desert and guide those who deserve.

And of course Happy Holidays and fruitful engineering. Don't worry letting your kid become an engineer :)

Quadrature Encoder

One of the essential things an autonomous rover must have (which mine didn't had) is one or more quadrature encoders. In fact even some non-autonomous vehicles have these devices. Most regular cars these days feature this type of sensor as part of the ABS system (see http://en.wikipedia.org/wiki/Anti-lock_braking_system). Very reliable and high-resolution sensors can be found in these (featuring 90 steps or more).

For this autonomous rover I found that 16 steps would be the bare minimum, and easy to implement with common components.

As I didn't want to modify the RC car itself (drill holes, cut parts, etc), I looked for a solution that would minimize the impact on the car. As such I found that a good option would be to use the inner ring of the wheel as a surface for sticking an encoder band. This band has 16 steps, and looks like this:

Now remotely controlled via IP

After some hobby time spenditure, the result meets the expectations. While it is a functional and simple (and a good fallback solution), controlling the car via a regular RC radio is not the most interesting scenario. Having a device that is mostly digital, being controlled by an analog receiver isn't quite the nicest thing one would want to showcase. With that in mind, and taking into account that all the necessary hardware was already there and working, I have decided to take a little bit of time implementing the necessary components to be able to control the car from a remote peer in a wifi network. As such all I had was to: