My purpose in doing these experiments is not for any practical reason such as using the core memory for data storage. Computer memory storage is already very much available today. But I wish to implement all the steps that are used in reading and writing this kind of memory. I have already a long list of terms and phenomena that are connected with magnetism in general, and ferrite cores in particular.
Hysteresis loop, domains, permeability, saturation, flux density, residual magnetism. A few years back, I was excited to learn that magnetism lies within the electromagnetic force, and actually stems from the spin of electrons in atoms, in very small areas called domains. In certain materials, the electrons can be forced to have the same spin, and this produces the magnetic force.
I am really excited in this new study and want to learn all about it. I might mention here coincident current, which is used to write to a particular core in a memory, by sending part of magnetizing current on one wire and part of it on another. Only where the 2 currents cross, is the threshold reached which is adequate to flip the core to the desired polarity.
Any way, there will be more!

Well, it entails accepting words spoken into a microphone, which will then be somehow processed electronically. So the analog sounds can be amplified and some kind of comparison made with a previously recorded template of some kind. One approach is to identify phonemes of which there are about 40 in the English language. Phonemes are the basic vowel and consonant sounds like oo,ah oh,ee, uh and k,t,p,ch,z,s sounds. Now I suspect my best tool for speech recognition will be DSP (digital signal processing). This involves changing the analog sounds to digitized form. It has been found that any analog values like
temperature, pressure, voltage can be processed much more effectively when they have been digitized. One computer byte of data has a binary range of value of from 0 to 255. So 2.5 volts on a scale of 5 volts might become a byte value of 127. After computer processing, the values can be changed back to regular voltage values.
So with analog sounds, we can digitize by taking numerous samples of the familiar waveforms. Sometimes it is hard to believe that the sounds of an entire symphony orchestra can be carried in a complex analog wave form. This sound
can evidently be effiiciently sampled and digitized as we realize when we listen to music on our IPOD.
I plan to experiment using my PIC microcontroller to sample sound signatures and find ways of comparing the digitized templates. It may even get to a case of pattern recogniton, since you can hardly expect to find exact matches. But it will be fun seeing what I find out.
I have already found there is a 40 pin speech recogniton chip for about $10. I may eventually wind up with something like that, but even setting that up will be very challenging as far as hardware and software implementation.
I’ll let everyone know if I am having fun with this next project.

I got involved with this recently when Harold Parker of Parker Products in Reading, MA gave me a handheld remote and an IR receiver on a very small board to play with. I also found a good article in SERVO magazine for January 2005 on this subject. The IR signals are modulated on a 38khz carrier so that other stray signals can be filtered out. Other carrier frequencies are also used.
One favorite mode of sending the codes is PWM (pulse width modulation). In this method the 0’s are send as a 400 usec pulse and the 1’s are sent as a 1200 usec pulse. I programmed my PIC microcontroller to read these pulses and store the resulting data in memory. Note that this takes place in about 40 msecs. Once I have stored the data I can display it at my lesure with any means available. With my machine I chose to print out a red line on a strip of paper. Below is a sample.

What I invision are some very loud speakers and effectivey an electronic carillon system. Other challenges will be to set up one or more of my PIC microcontrollers to generate the original frequencies for different tones, and signals to drive relays that will turn power on and off in parts of the circuit to achieve the decay. I will be working with a range of big fat electrolytic capacitors
to provide a source of diminishing power when the main power is removed.
I will display some of my circuits as I go along. Eventually I hope to present some sound clips here on my blog. This should really be fun!!

hi George
Last night I was writing some notes in my
journal and when I headed back to bed I
was saying to myself
“Larry Keegan – welcome to the world
of object detection and avoidance,
distance measuring,
wall-following and room corner navigating!!”
What I suddenly had a vision of was endless
complexities of working with 1,2 or 3 or more sensors
and the possible motions of the robot in identifying
and avoiding objects.
Yesterday I had just received in the mail
4 Sharp GP2Y0D340K sensors. You may be familiar with
this. It goes active low when it encounters an
object less than 40 centimeters in front of it.
I soldered one to a PC board, added a couple of components
and it tested nicely (but not hooked up to a robot yet).
What you have already been dealing with is
the vast amounts of software and accompanying algorithms
that may be necessary to utilize the sensing signals
and determine on a course of action for the robot.
There is also the possibility of one rotating sensing element
and the corresponding calculations that would be necessary
to ascertain the existing environment.
It also occurred to me that this might be an excellent area
for pattern recognition and neural network technology
which I have dabbled in years past.
After all this I will probably start out with a single
sensor up front, but I foresee a more practical
arrangement will be 3 sensors in front pointed in different
directions.
Well, George, if you don’t mind I am going to throw this whole letter
out onto my BLOG, to let people interested know where I am
with the robots these days
Maybe you will share with me just how big a deal this business
of sensing obstructions and walls and mazes has been for you
and your sophisticated robot.
Hoping to hear from you,
Larry Keegan in Stoneham,MA