Walking slowly, they got in the town through the main road. It was a group of about fifty people, all dressed in white and barefoot, wearing only a string of beads as a necklace. The boss, a huge black guy, distinguished by the two necklaces he wore, instead of just one, carried a sign that read:




The curious glances of the population didn’t shake the strange march, which ended in the main square, where they "camped" in a large circle.

- Will you be peaceful? - Someone asked.

- What do they want? - Inquired another.

- It must be a religious group from these African cults which are now in fashion! - Someone "more enlightened" tried to explain .

The situation was much calmer when the sergeant of the local guard was taking information from the head of the group, and returned with reassuring news:

- They are only on pilgrimage in search of "owamukela" and will not stay more than two days. They are peaceful and are tired. They just wish to get some rest!

- "Owamukela"? What is "owamukela"?

- Do not ask me! - Answered the officer - I know as much as you do. It must be some "entity" of their worship. They say that their "master" had the pilgrimage to find him! ...

- But how will they know when they found him? - Someone asked.

- They say a "sign" unmistakable will be sent, which will enable his recognition...!

After the initial excitement that the "phenomenon" caused, the small crowd that surrounded the square dispersed itself. Soon everyone knew that the group was harmless and no one else was bothered by their presence.


Oblivious to what was happening, Professor Ventura worked enthusiastically on a new project. Bart and Bert arrived just in time to see the strange device that Professor was "installing on himself".

- What the hell is it Professor? - Bart asked.

- Will you electrocute yourself Professor? - Bert completed the interrogation.

The professor, working constantly in many wires which came out of a box attached to his waist explained:

- It's a race stimulator! A new wearable idea.

- Wearable?

- Yes, "wearable". I’ll explain it better: you know I like to run two or three kilometers a day to "keep fit", and the heart in order. Medical advice! Well, I’ve noticed it's kinda difficult to keep a pace, and I came up with an electronic device to help.

- A pacemeter? - Bart interrupted.

- Not really, a stimulator! The idea is to apply on the muscles involved in the process of running, external stimulus at the right time, by a "clock" that will determine the rhythm of their contractions and sprains.

- Like a computer? - Bert questioned.

- Yes, that's right! The "pace" of the operations which a computer does is given by a clock or a clock circuit. It works as a conductor that synchronizes all the internal circuits so everything works in harmony. My muscles, to make me run, also need something to make them work in harmony, so I "invented" it.

- Why don’t you just use a metronome? Haven’t you seen some pedometers that produce little noises which help the runner keep the pace? - Despite of the question, Bart knew the professor would not be satisfied only by little noises.

- Using direct stimulation from a stimulator you can get much more! In addition to keeping your rhythm, this device can also make you run almost "automatically"!

- Interesting! Just adjust the speed and you will run even if you don’t want to! But what if you need to stop? - Bert had doubts about the functionality of the "thing".

- It isn’t like that! I set the level of excitement in a very low level, in a way enough to just get a slight contraction, but without losing control over the movement! I've tried it and it's very interesting, because it is as if there were an "invisible hand" holding me and helping me to run!

- Wow! This could make a huge success with lazy runners! - Bart said looking at and poking “his friend’s fat”.

The professor didn’t get bothered with the remarks which indicated how his invention could "trend" as an IoT product, or the internet of things.

- I may have in the future a driving clothes for racing, with embedded electrodes and still sending information to a mobile phone or the Internet to a file the information in the clouds. The wearable are in fashion. Clothes, shoes, watches and other things that embody an advanced electronic form.

- But how does it "technically" work? - Bert asked.

Stopping working on the wires, the professor explained:

- Have you heard of Arduino? Well, the Arduinos are small microcontrollers which can be programmed by a computer to do anything!

- Anything? - Bert was skeptical because he didn’t know the device.

The professor noticed it and decided to give further explanation:

- Most current electronic devices can be very complex, summarizing as many functions as possible in a few chips. These chips are called ASICs and are nothing more than microcontrollers, similar to those we find in computers. ASIC means Application Specific Integrated Circuits. In it we have several sets of logic functions normally NAND gates which can be interconnected by external programming so as to obtain any digital function more complex than the chip. This means that the manufacturers can make all the chips the same and the users determine, by programming, what they will do. One of the most popular series of microcontrollers of this type is formed by the Arduino.

Taking his breath briefly, the professor continued:

- An Arduino board has a simple microcontroller, similar to any processor in a motherboard and a memory that can store the program that says what it will do. When we buy an Arduino board it comes "empty".

- Empty?

- Yes! You get one of these boards, connect it to your computer through appropriate connectors, and put the program, let’s say to trigger certain devices of an alarm system, when the sensors are activated. The program says that an Arduino should turn on, triggering, for example, an alarm and even automatically dialing a phone to call the police, or notify the owner of the house, if he/she is in another location.

- From a beach house, for example!

- Right! - Continued the professor - it is a way to practice electronics without many components and also to connect a computer to other devices, which it can control, or simply determine what they have to do. As I said, we can do almost everything with them!

Bart realized that the professor added an "almost", but let the old master continue without saying anything:

- An important application is in the small industry: you create a product to perform certain functions. It's what the "makers" do using an Arduino and other microcontrollers like the PIC, you establish in a program these functions and simply turn on the devices to be controlled by an appropriate interfacing board. Everything is very simple. "Electronic" washing machines, microwave ovens, answering machines are examples where we have these chips, controlling everything they do and still connecting to the internet. It is the internet of things or IoT.

- And then you used an Arduino to make you run even if you don’t want to?

Without a change the old master went on explaining:

- In this box we have an Arduino Uno, very popular, which can be purchased with a programming “set”, and this version supports up to 1 Kbytes of a control program loaded by a common computer, through its serial gate. An internal oscillator sets the pace of the race which is adjusted by this potentiometer...

- The "accelerator"! - Bart joked.

- The Arduino software determines which outputs should be activated, establishing a sequence for the stimulation pulses, and also determining the locations they are applied! For example, first on my right leg and my right arm, then my left shin and my left arm and back muscles, and so on! ...

Opening an app on his phone, the Professor showed a series of animations that showed the functioning of a person's muscles when running. The points of excitement in a sequence that would be required to move to run were highlighted by arrow indicators. The professor explained:

- I made a thorough study of the excitement points, and their sequence! There are 26 points fed by a sequence of 9 pulses, repeating then the cycle!

- Wow! - Bert was amazed.

The professor had not finished yet:

- The pulses generated by the PIC are brought to transistors which feed 9 small high voltage transformers, providing nearly 800 volt output to the electrodes. It is what we call Power Shield. The electrodes are connected in a way that the microcontroller through a decoder provides the final pulse sequence in the desired pattern. In the output transistor, before going through the transformer, we have something important: the intensity adjustment of the stimulus!

- Ah! There must be a control, as with 800 volts you would "fly" and not "run"! - Joked Bart.

- Of course! I adjust the pulses with the microcontroller signals applied to the bases of the transistors drivers to get a stimulus only in the intensity required for a slight contraction! Now help me here!

- And the program to control all this? - Bart wanted to know more.

- One advantage of Arduino I'm using is that it is very cheap and also simple to use, can be programmed with a software available on the Internet . Thus, from the appropriate software, I made a program that sets at the right time, the exact sequence of pulses that I need to drive my muscles. It was just connect the computer to the Arduino, download the program and that was it!

With that said, the professor asked Bart and Bert to keep helping wearing it, with plasters, the 26 small metal flat irons which were the excitation electrodes spread throughout his body. The connecting wires for his legs and arms were thin and also secured by small plasters, almost all imperceptible.

Wearing his race "uniform", the professor was wearing shoes, high-top socks, shorts and a T-shirt. The little device, installed in a small box, was attached to his waist. The electrodes were throughout the body: two inside his socks contacting his shins, two on his "leg calfs" and two on his thighs. There were also electrodes on his arms, his back and even his belly! ...

- To drive the diaphragm! It is important for breathing! - Explained Professor Ventura.

There were no more doubt for Beto and Cleto, that Professor was going to do a test drive. Bouncing around to warm up and make adjustments, the professor turned it on! Controlling the intensity and the pace, in a few seconds he found the ideal spot, leaving the laboratory door on a race pace! Bart and Bert followed.

Running at speed, the teacher got to the main street, and headed towards the square, which he intended to cross and then go back!

- It's great! It feels like I’m not even running! - The Professor commented trying not to change the rhythm of his breathing.

When he entered the square, the professor came across a strange group that was camping, but he didn’t change his mind about crossing it. Bart and Bert were more cautious and decided to stop. Sitting in a circle they seemed friendly and there was nothing to fear. The professor, however, to get where he intended to go should cut the "religious circle" and it was just as he did it that things started happening!

Some "crash" on the stimulator circuit, perhaps due to the professor’s strong and firm steps, made at the same time the speed of the "clock" increased, the electrode driving order became random and the voltage of the small transformers rose to the maximum value!

What people saw then was amazing!

The professor who was running normally, right in the middle of the "camping", changed pace beginning to squirm, raise and lower his legs in weird and disorderly fashion, waving his arms desperately trying to take off the electrodes that were giving him tremendous shocks! As they were happening in the way of uncontrolled impulses, the stimulus caused a strange dance, as if he had filled his clothes with ants stepping barefoot on flames! It was as if "he was taken by some spirit," someone would say after witnessing the unusual scene! And that's just what the members of the weird religious group thought.

- Hey! Ugh! Ouch! Get it out! ... Wow! Take this "thing" off me! Get it out... - He was screaming, jumping and desperate!

The "contortionist dance" lasted for at least two minutes before Bart and Bert could help, coming to his rescue, turning off the device.

- Wow! - Was the Professor’s relief exclamation, sorry to the bones to have closed the prototype in a box with so many screws!

However, when he and Bert realized where they were, they got startled: the religious people were all standing open-mouthed and wide-eyed, watching everything, but they did not say anything! Just stared... And stared...

This time the leader got up and went towards the professor, who was scared, sore and thinking of something worse, he did not wait to talk! Helped by Bart and Bert, he sought quickly to get out of there!

- Back to the lab! - Was the only thing that the professor could say, still half shaking and breathless.

When they walked away, they could still hear in an enthusiastic tone comments in some unknown language, and something in the middle sounded like "owamukela umoya"!


Professor Ventura returned to the lab still dazed and after getting rid of all electrodes and adhesive plasters, placed the device on the counter to check the cause of the "crash".

- Now, see! - It was his exclamation, to analyze the printed circuit board device - A bad welding in a capacitor opened the circuit, increasing its frequency and with rhythmic jumps, the aluminum shielding I to put on the back of the case touched the copper side of the diode matrix, changing the sequence of the pulses as well as "elevating" the output voltage!

- It must have been a huge discharge! - Bart said.

- Oh boy! I’m still shaking from it, but the problem is that I think I scared those people at the square! By the way, does anyone know who they are? - The Professor asked.

Bart and Bert shook their shoulders and nodded negatively.

The matter was forgotten until the next day, Professor Ventura and Professor Crick, principal of the Technical School, were going to leave the school from the front door, when faced with an unexpected scene: the group of fifty people in white was camped exactly in the entrance garden! Bart and Bert had seen when they arrived; they approached, along with other students.

The teacher got downstairs with the principal, considering not to pay attention to the fact, as he had already received the news that they were peaceful and were just on pilgrimage. It was then that all the religious people in white turned to the professor and rose up with fingers pointing at him, began speaking something incomprehensible. The leader of the group, identifying Professor Ventura from the day before, immediately waved his arms for silence and, wide-eyed, turned to the old master.

The huge black gentleman then walked towards the professor half surprised, half scared and stopped! Professor Crick also stopped! He didn’t know what to think.

Addressing directly to Professor Ventura, the leader spoke with serious and respectful voice:

- Our search is over! We found Owamukela Umoya!

Professor Ventura without knowing what to do, what to say, much less what was "owamukela", not caring who the hell they had found or not, only waited for the religious leader to complete his speech :

- Owamukela Umoya in our language Swahili (South Africa) dialect, means "He-who-contacts-the-spirit" is our master, said we would receive an unmistakable signal when we find him! What we saw yesterday leaves no doubt: It is you Sr.!

And removing one of the bead necklaces he was wearing, he put it ceremoniously in Professor Ventura’s neck under the incredulous look of the principal and the students.

Moving away three steps without turning, the leader bowed and the whole group of religious people, accompanying him, shouted in chorus three times:

- Owamukela Umoya!

The teacher did not move! He was paralyzed! The group turned back, and repeating in chorus the same words, walked away slowly in procession, leaving the Lemon city to return to "who-knows-where" satisfied and happy to have fulfilled the mission of their master!

The school principal couldn’t believe what he had seen, and with the group away still leaving, with both hands on his hips, looking serious at the crestfallen and still stunned Ventura, he said:

- I'll be damned if that has something to do with electronics! Do not tell me that this time you "invented" a device which “makes contact with the beyond” (And that was it!) I can’t imagine how, but as for you everything is possible! ... And that the "crazything” also has something to do with electronics, I'm sure! I guess you owe me and everyone else a good explanation! ...

Bart and Bert, who were a few feet away, were trying hard not to laugh!