Plastic Logic bites the dust

-

I was very excited by what this company was about to deliver. But unfortunately they have cancelled the launch of their QUE electronic ink device.

In the mean time, Amazon and Barnes & Noble get into price fight that drove down the prices of their entry-line ebook readers to around $140. This is around halve of the original price and what is better, more features are added to the new devices (ie: wifi).

I really like the new Kindle 3 and over the summer I've been reading a lot on my 6" Papyre ebook reader. I've come to the conclusion that 6" is more convenient than the larger size of Kindle DX for reading novels. I'm kind of disappointed with KDX as it is not good for letter-size documents (or A4-size) in my opinion.

I've used a lot our iPad over the summer but just for browsing and, more importantly, to use the Maps application to find where to have dinner or to look for the route to a destination (very handy when travelling). However I've read not a single book with it (though I loaded a bunch of them just in case). What is worse, I've learned that some of the PDF files I've loaded on iBooks completely crash the application once opened. And when this happens the only way to get iBooks to work again is to remove the offending (opened) PDF file from iTunes and to re-sync the iPad . If not, every time I open iBooks it goes to the same PDF and it crashes iBooks before I can switch back to the library view (Mr. Apple, please fix this soon).

In the ebook market in Spain, vendors seem to believe they still can keep prices as they were last year (around 250€-ish) regardless american vendors have halved the prices. Should I were about to buy a 6" now, I only would consider a Nook or Kindle (because of prices and features). While happy with my Papyre I can see the new Kindle has many improvements.

Comments

Post a Comment

Popular posts from this blog

VFD control with Arduino using RS485 link

-
Image
Variable Frequency Drives ( VFD ) allow the control of spindles so speed can accurately be controlled and a detailed acceleration profile for the spindle and reverse rotation can all be handled. In essence a VFD is an three phase inverter for three-phase AC motor. I am using a popular (I mean cheap) Chinese VFD and though the reference manual is not great, I could see there is a built-in RS-485 port. I usually control the start, stop and speed selection using the keyboard on the unit but I thought it will be more useful if I could control everything from the same Arduino is doing our CNC table control. Some cheap RS-485 off eBay and some lines of code later, I can start, stop and change the speed from an Arduino. What a cool thing to have! Some configuration of your VFD are needed before you can use it like that.  You need to set PD163=1 (I am using address 1 in the code). PD=164=1 (for setting serial to 9600bps) and PD165=0 (for using ASCII and 8N1 character format)
Read more

How to get sinusoidal s-curve for a stepper motor

-
Image
After some experimentation, and delving a bit into the math of motion, I realized there can be a significant difference on the motion of a machine by just making small changes. A common and popular approach to smooth one axis of motion is to use a trapezoidal speed pattern, where acceleration and deceleration are uniformly accelerated movements (aka constant acceleration motion) separated by a portion happening at cruising speed. The problem comes with the fact that, while that approach is simple to understand and to code, it does contain sudden changes in the acceleration, that show as spikes on the acceleration derivative, called jerk. These sudden changes in the acceleration translate into undesired vibration in our machines. Most of that can be eliminated by selecting a motion pattern that does not contain sudden changes of acceleration. If we chose a mathematical function for our speed whose second derivative is continuous, then we reduce system vibration quite a lot. One ma
Read more

Stepper motor step signal timing calculation

-
Image
While we use stepper motors in many devices, the timing of the step signals is not always well understood. Most of us can see how a fixed speed is a bad idea unless the speed of motion is really slow, but it is fixed speed what is really to generate with simple code. You just can use the Arduino Blink example to send a fixed frequency of pulses to a stepper motor driver. If too slow, just reduce the delay value. But for most real-life applications variable speed controls will perform better. These systems will speed up the motor to a given maximum speed and it will slow it down to stop at the desired step count. But understanding the math behind this process is sometimes not obvious. Let us start with the simple case of the so-called trapezoidal speed motion profile. Here motion takes place in three phases: acceleration, constant speed (cruising) and deceleration. But the point is how can our code create such a behavior. Stepper motor drivers usually accept two signals to control
Read more