One scene, which had ceased to be common for some time, surprised Bart and Bert as they approached the house of Prof. Ventura: Satur Spendthrift, the mayor, with his delegation hurriedly left the house of the old master, who dismissed the "preboste" friendly.
For readers who do not know, "preboste" was a Brazilian name given to the former military magistrates who were characterized by the "royalty" of their position. The imposing posture of the mayor had led some of his political opponents to give him this "nickname" that stuck very quickly! Since the prefix “boste” in Portuguese reminds a profanity, which in English starts with SH and ends with IT, you can imagine why it was considered so “funny”.
The newspaper of the city, in the hands of the opposing party, only used this title when speaking of the mayor. In fact, in informal conversations, everyone used the title "preboste"!
The mayor did not really bother much about the title, but he had a bit of grief about the double meaning given to the word, and its derivatives which people acquired since the last events, that the reader who accompanies the stories of Prof. Ventura knows very well!
Bart and Bert approached the Professor, as soon as the mayor left, and asked:
- What did Preboste want this time? Is he no longer angry?
The Professor still remembered the fateful case of the swallows in the square that had forced him to be "gone" from the city for a some time! However, as the months passed, the case became a "joke" and even brought some prestige to the city: many came to visit the city and with great interest pointed out:
(*) See the story "The dysenteric oscillator" (VENT002E) what happened.
- Is here where the “preshitting” shitted himself?
Or else:
- Let's take a picture here in the place where Tubald "deleted"! ...
Even a software company was in town to try to get the fateful program of Professor Ventura, hoping to sell it as an "electronic laxative”, a typical computer-age product! Certainly a very successful wearable.
- Imagine! A mobile app to help people with constipation!
- With a GPS to search for the nearest restroom ...
The result of this company's visit was the only serious incident, the mayor had to expelled from the square a TV team hired by the software company which wanted to record the App-laxative commercial at all costs!
The Professor, after these memories, invited Bart and Bert to enter: they would have a job joining computers and electronics again!
- No ultrasounds, I hope! - Bert had many bad memories of what had happened in the case of the swallows!
- No, boys! - The thing is much simpler and does not involve unknown programs or circuits: It is a simple assembly of a system of rhythmic lights, some mechatronic devices and something more controlled by a computer!
- Rhythmic lights? - Bert asked.
- Yes! The mayor noticed that all the neighboring cities have their light fountains, but ours don’t! The thing is he does not want one like the others! He wants something different and much better!
- And then there is where we come in! - Bart got up from the chair to hear better.
- Yes, the idea is to make sure that, in addition to the simple spotlights that flash and light the water jets, these jets get the music of the speaker system and even produce special effects controlled by a microcontroller! The mayor saw this, I don’t know where, and thinks we can do the same here!
- A microcontrolled and rhythmic luminous fountain! It's something interesting, and apparently not dangerous! - Bart feared because of some failures of previous projects, but calmed down a little.
- Exactly! Being something relatively simple and having no apparent danger is why I accepted, and I already have a good idea of ??how it should be made!
- Wow! Already? - Bert was surprised at how quickly the teacher had his ideas.
The project of Professor Ventura really was not anything simple when analyzed by "ordinary" people! He sketched on the blackboard how the system would be, which was soon easily assimilated by Bart and Bert. They would help with the assembly and installation:
- Let's connect the analog input of a microcontroller by applying the audio signal of an amplifier system which will sonorize the square in order to process this signal. The sound that must be amplified and reproduced is constantly analyzed by a special program which we are going to develop. This program is the only "secret" of our business! - the professor said that winking.
- What do you mean? - Bart asked curiously still having no idea what was coming.
The professor continued:
- What we do is to synthesize "three-dimensional images" of the sound using water jets and bright spots of primary colors!
- What? - Bart and Bert were frightened. The professor realizing that he would need more complex explanations decided to start it from the beginning:
- You know that the colors we see can all be synthesized from red, green and blue. It is what makes a display of a television or video monitor.
- Yes, RGB! From other words red, green and blue! We know how this display works! - Bart said confidently.
The professor went further:
- Exactly! You can represent the colors on a three-dimensional chart in which in the X axis we place the blue, the Y axis the green and the Z axis the red or another order. By combining the values ??of X, Y and Z we can define any color. This means that in the space delimited by these three axes we can get any known color. All possible colors to produce will be in the volume delimited by these three axes.
- Do televisions and video monitors do that? - Bert's doubts were addressed to Professor Ventura, who continued:
- Yes! When we want a point or pixel on the monitor screen to have a certain color, this color is determined by three scanned or coordinate values. If for blue we use 5 bits, for green 6 bits more and for red 5 bits more, we will have 16 bits of "information" about colors that lead us to 2 raised to the exponent 16!
Bart, quickly picked up his calculator:
- Wow! 65 532 different colors! Ah! So that's why on some computer monitors we find this value!
Bert had noted one important detail:
- But why use 6 bits for green and 5 for the other colors?
The teacher knew the reason:
- Because it was verified that our eyes are more sensitive to this color: Since 16 bits are two complete bytes, in the division by 3, what was left was destined to green so that this color could have more variations and therefore more definition!
- But what about the fountain?
- Ah! What we are going to do is simple: we will have two sound sources, one external that can be a set of microphones and the internal one is a pendrive with an MP3. Let's imagine that we are using an Arduino. The sound of the pendrive can be processed by the spectrum analyzer program that will act as a filter by turning the various frequencies into values ??that can generate information which matches the three primary colors. These values ??will actually produce control signals that at the same time triggers the basic spotlight and a set of solenoids.
As Bart and Bert nodded, confirming that they understood the teacher, he continued:
- The signals obtained at the output will be used for two types of controls. In one sector they will move to a PWM amplifier and modulation stage that will activate through shields with optodiacs, a triacs set of good power. The optodiacs are important to give safety to the circuit, since they isolate the high voltage network that must feed the triacs and water valves of the delicate circuits of the microcontroller!
- Safety is everything when we work with the power grid voltage! - Bert commented.
- In the other sector, a set of triacs will control the spotlights, but each of one of the basic colors, so that we will have six triads of beams of different color lights, each controlled by the signal resulting from the processing of the microcontroller. Thus the triacs of each channel will be connected in six triads of solenoid valves, the type that interrupts and lets the water through washing machines. You know, these valves are powerful electromagnets that when they are run through a current, pull a plunger, which then lets the water through. When de-energized, a spring brings the plunger back to the position that interrupts the flow of water.
- I'm beginning to understand! - Bart said - When we have a pulse of sound of a certain frequency, the microcontroller analyzes the sound and generates a signal of control: the spotlights then blink each one with a well defined intensity generating a color determined by the program and a jet of water strongly jumps! The stronger the sound of that frequency, the stronger the jet of water and a completely different color!
- Yes that's right! - the Professor confirmed -The final effect will be interesting: As the music is dynamic we won’t simply have blinks, but variations of colored lights and at the same time the intensity of the water jets! These effects will be determined by the microcontroller program that generates its own control signals from the music! This differentiates our fountain from others where the light only blinks with the music!
- A "dancing" light fountain! - Bart concluded.
- More than that: dancing and microcontrolled! - Bert added.
- Wow! A good name to suggest to the mayor: Computerized Dancing Fountain!
The professor paused a moment to imagine his work: a Computerized Dancing Fountain! His modesty prevented him from imagining also a sign in front of the fountain with the following words: "Computerized Dancing Fountain by Professor Ventura" - "Creation of the Lemon city’s Electronic Genius".
Back to the “real world" the professor invited the boys to make a list of the material necessary for the assembly. They would have to submit the idea to the preboste, I mean to the mayor!
Satur Spendthrift, the preboste, I mean the mayor, carefully examined all the lists, schemes, and plans of Professor Ventura. Kind of suspicious, he still called his advisors to give his opinion. No wonder he had to be cautious: the professor could reissue the "strange preshitting vibrations" of the swallows case, as they came to be known, and he did not want to take any chances!
- All right, Professor Ventura! We believe that there is no danger in installing this equipment! You have our authorization to execute the project! We will also give you some employees to work at the fountain!
The fountain already existed, in fact it was an old water tank with some frogs that croaked all night long! The people nastily said that it was the "croaked" fountain of the "preshit", comparing it to the "singing fountains" of the neighboring cities!
The work of reinforcing and adapting the old fountain took a few weeks, but it was great! Under Professor Ventura's guidance, twelve floodlights had been installed, four of each basic color pointing to the center of the fountain. Six solenoids in a circle in the center and six solenoids on the sides fed special water jets that threw water up and to the sides! Since the water should have good pressure, a compressor pump was installed. The whole system was controlled by an Arduino where it was running a software created by Professor Ventura, and several control shields with a high power Triacs battery.
- It must go up at least twenty meters! A spray of the purest water! - proudly commented the professor showing the service to the mayor, after taking into account the pressure of the pump and the PWM modulation of the circuit.
Ah! Water was also a problem to be considered: in the past the fountain was fed by a natural blanket coming from the hill. But the city grew and the hill became urbanized: the water disappeared!
Analyzing the situation, Professor Ventura, with technicians from Lemon city’s Department of Water and Sewerage, found the solution:
- Underneath the fountain there are the main pipes that carry the water of the city. Just pull a branch and that's it! We'll have plenty of running water.
The seemingly simple solution, began to complicate from that moment:
It is not known “why on earth” they called old Simon Plugpipe to make the derivation! The ancient employee of the department was very competent in carrying out water and sewage connections, but he had a small defect: he was squatting and left-handed!
- Be careful! You pull the "T" of the pipe that comes from the right, and pass it to the left and not of the pipe that comes from the left and pass it to the right, and then turn it to the left again, which is the sewer. The two pipes have the same thickness and it's easy to make a mess, understand? - explained the engineer who helped in the works holding a plant along showing it to Professor Ventura!
Faced with news of the reopening of the fountain, everyone in the city was exicetd and one of the most enthusiastic was... Tubald Waethercock! For those who do not know, Tubald was the band's musician, the most "powerful" tuba in the region. Forgetting the problems that had occurred with the swallows, Tubald once again fervently polished his instrument every morning, waiting for the big day, when he would play again the marches of John Philip Sousa, of whom he was a fan. In the afternoon he was excited for the rehearsals with Maestro Ronald who, with his pride of being a great artist, did not want any mistakes at the big event!
- After all! What could go wrong this time? - it was the answer he gave to Mrs Ginevra Weathercock who, worried, still had bad memories of the last performance of her husband!
But there were a few minor problems that were occurring in parallel with the joys of the people: the "T" of the tapping of the water pipe was not available in the city hall warehouse and had to come from the Capital, which took longer than it should have, to the despair of the Mayor and concern of Professor Ventura!
- We need it for the tests! - the Professor exclaimed showing his concerns.
- Calm down! It's already coming! -The Engineer Rodrigues of the Water Department.
When the "connection" of PVC arrived, it was almost time for the inauguration, which led the Mayor to rush more than its installation, but Simon was not used to doing things quickly!
In the dark hole that gave access to the pipes under the fountain, the water department employee was really confused. The explanations of how to turn on the "T" shuffled in his head!
With so many "rights" and "lefts" in the explanation of the engineer, for who is squint and left-handed, and still had a strong cold, he no longer knew in which pipe to make the derivation and what the reader should be expecting happened: he hooked it up to the sewer instead of the water!
All this would be fine if there had been any time for a test. However, the call was made "in time". Even under protests from Professor Ventura, the preboste, I mean the mayor, who did not want to lose "political dividends" wouldn’t accept to put off the inauguration, which would surely give much subject to his political enemies.
- The fountain will be inaugurated today! And just in time. - The irritated preboste was beating hard on the city hall table as he faced the arguments for trying to postpone it.
The professor looked at the clock worriedly: it was only half an hour before the "big event"! Even if he wanted to run a test at that time would be impossible, because the square was already taken by city citizens that awaited the great event.
Even the band had already settled in the bandstand before the fountain and was preparing to start their musical programming.
Tubald was radiant. In his new uniform (the old one had been buried, for reasons known to the readers), and with many shining bronze buttons, he held his beloved and shining tuba very fondly!
Professor Ventura, beside the microcontroller and the programming laptop, carried the control program and tested the other circuits of the valve and the spotlight system. At the same time he typed the commands, he gave some final instructions to Bart and Bert, who were very worried:
- There won’t enough time to test the water! Are you sure it is working perfectly?
- We ran a test on the control part, Professor, and that's fine: when we put the music from the sound system the spotlights will normally blink within the programmed patterns! Checking the fountain, we noticed that all solenoids "pop" at the right pace, which means they are being triggered!
- The compressor pump is OK, too! The pressure gauge indicates good pressure.
- Just open the register on time. - Bert said as he had inspected it.
- Not bad! At least we know the water will go up! I am only afraid of the force with which the water will rise, but as long as the tips of the jets are up and into the fountain, I believe we won’t have problems! - The professor said more relieved.
- Yes, we also took care to check that all the nozzles are tight. They are movable, and a change of position could ruin the effect!
Satur Spendthrift, the "Preboste", arrived on time, with his delegation of counselors, secretaries, advisors and many influential people of the county. Professor Ventura was invited to climb the platform because he would be honored for his "contribution to the success of the project ..." Bart and Bert were in control of the equipment.
The band played Sousa's marches excitedly, and it was already dark. The opening time of the fountain had been planned to be after the sun set: this was fundamental to the effects of light!
The mayor's speech was inflamed and everyone applauded. Proud and elegant in her white dress, the first lady of the county was next to Professor Ventura, from time to time smiled and waved to an acquaintance!
Finally, it was time for the inauguration and for this there would be a different electronic configuration in action, planned by the professor, who in a "snap" suggested to the mayor: a set of microphones was installed before the band, and at the conductor's command, when she played the Chords of a carefully selected gait, the sounds would be picked up and processed by the well-crafted effects program loaded into the microcontroller. Properly modified for the numerical controls they would trigger the "dancing" system of the fountain. In short, the fountain should follow the band pace at the time of opening!
The band's music would make the show of "lights and colors" at the opening of the fountain!
Tubald was proud, for one of the microphones had been placed just in front of his "powerful" instrument! He would strive like never before to be the best! They had informed him that the serious tone of his tuba would trigger, almost exclusively, one of the "channels" of the fountain, it would have a special processing, and this was added to his "responsibility"!
- Red! The bass tone of my instrument will generate beautiful flashes of red light! - Tubald was proud and repeated Professor Ventura's explanations, caressing his precious tuba.
The mayor finally announced:
- And now, the great moment! Under the music of the "Glorious" Musical Corporation of Lemon city, our beloved people will have the opportunity to see for the first time the pure waters of our subsoil dancing with all the vivid colors of nature, fact only possible by the competence, genius and inventive spirit of the great Professor Ventura!
Everyone applauded and there was silence when Maestro Ronald raised his arms.
Meanwhile, the compressor pump worked uninterruptedly and at full power in order to guarantee the pressure of the water, I mean of what entered by mistake in the system, and that pressure was not low!
It was given the order to trigger the system and with a signal, the band "attacked" with another march! Everyone was looking intently at the fountain waiting for the "clear and powerful" jets of water that the preboste had announced, but what happened was quite different...
The liquid flowing through the pipes to the jets was not and did not have the same "consistency" of water, and this caused a heavy overload on the compressor pump vibrating dangerously! With several "balls", the smelly fluid stuck next to the jets while the pressure increased tremendously in the system, following the rhythm of the band!
The mayor realized that something abnormal was happening, just like Maestro Ronald, because nothing was "happening" to the fountain! Thinking that the problem was the level of music, the conductor still gave a signal for the band to play stronger.
Tubald, the most "powerful" tuba of the whole region was the first to respond to the command, and it was a disaster: the musician's face turned blue, which was normal when he played too hard, his eyes came together, and he blew!
This time the note did not come down, but above, and the microphone in front of the tuba was practically "stuck" with the powerful sonorous vibration transforming it into an electrical signal of great complexity that processed by the Arduino generated a complete byte of "ones" including the parity bit! The strange command signal, which wasn’t foreseen in the program, the power interface was triggering several triacs at the same time, given its intensity! That was enough to the pressure of the bomb finally overcome the stickiness of the smelly fluid which then gushed in all directions in the form of huge "balls"!
Splash! Splash! ...
The effort and pressure had changed the orientation of the jets which then pointed in totally unpredictable directions!
The "balls" looked like flying grenades which depicting precise curves in space began to hit their targets!
But the first, which corresponded precisely to the bass sounds of Tubald’s tuba, and therefore accompanied by a "beautiful" blood-red glow that gave it the appearance of a "flaming meteor", went up performing a perfect parable and fell right inside the tuba of the poor musician, clogging it up!
Ploft!
The musician did not see the "shot," because he was practically with his eyes closed, due to the force he made to play, but he realized that something abnormal had happened! He pushed again, and nothing! It was really clogged!
In a snap, however, Tubald then had an unhappy thought: “If blowing it does not come out, then let's try sucking”
The taste was awful: something like a "slapped killed monkey" stew with galoshes tea and umbrella cape! Tubald, acquiring all possible colors, gasped, and without even having time to take off the mouth of the instrument spat through the tube itself what was left of that "foreign body" spreading it in a kind of spray! It is said that the sound emitted was something that was between the howling of an elephant and the whistle of the Titanic! The opinions of those who heard differ, but the fact is that the powerful musical note was not on the march and even frightened the master!
A little boy, watching the musician, at that moment, pulled his father's jacket and said:
- Look, Daddy! There's another light fountain there.
If it was not bright, at least it was colorful!
Tubald was now green, squint, choking and having almost "turned inside out," dropped the tuba and ran away!
- Argh! I'm poisoned!
Most interesting of all is that the sound of this note was also picked up by the microphone and served to feed the electronic system! Professor Ventura later commented that, for the first time in the history of electronics, a "hybrid" circuit was obtained in which the feedback signal of a program changed "consistency" in its course, becoming a sewage ball. Interesting thing, from the purely technical point of view, of course.
- It's not in any manual!
The maestro, on his back, did not notice what was happening at the fountain and so he continued to lead the band with the same strong rhythm and the band musicians obeyed. The music continued and new “balls” accompanying its rhythm, now in greater quantity, were fired randomly and in all directions! The strong pressure of the compressor caused the effort in the jets to constantly change their positions so that each note corresponded to a "shot" that was pointing to a different location!
The second "ball", almost simultaneous to the first, also deserves to be quoted, because it hit the "long forehead" of the preboste, I mean the mayor, who was actually bald! The splashes hit several people around him, leaving a terrible smell! The first lady in her beautiful white dress was one of those stricken! The mayor drew back in fear, not before hearing from the crowd an exclamation that was already familiar to him, and which used the so feared verb:
- Hey! The preboste is "preshitted" again!
Once again, there was no time for laughter, since the "preshitting" was general! Then a shower of sewage fell directly on the crowd that dispersed in panic!
Bart and Bert realized what was happening too late to avoid the first shots, and that was fatal! An individual standing nearby, noticing what was happening and seeing a "shot" coming directly towards him, tried to run and tripped on the cable connecting the microcontroller to the control shields, turning them off! With the microcontroller disconnected the power circuit "locked"!
- Turn the system off! Turn the system off! Shouted Professor Ventura desperately, trying to get off the podium.
Bart and Bert still tried to cut the power and with that disable the triacs, but it was not possible! The panicked crowd prevented them from reaching the power circuit which was centered in a box below the fountain! It was out of reach and therefore out of control!
- We can’t! - Bert shouted shielding himself from the "bombardment" with a garbage can lid.
The song only stopped when a “beautiful ball” of sewage struck right on the Maestro Ronald that almost fell off the stage! At this moment the glorious Musical Corporation of Lemon city “disintegrated” with the musicians in a panic, which increased the confusion even more.
The mayor was dirty and nervous, left the place accompanied by the first lady who cried, and with them the dirty and "preshitted" delegation. Some slips on the square made the situation worse for some who had taken only light strokes!
- I never thought my “morality” could be so shaken by something that could come from underneath - the preboste exclaimed nervously on the run.
The fountain still continued to "shoot" for some time!
It was with a lot of sacrifice, after some "shots" which hit Professor Ventura, Bart and Bert arrived at the power plant that fed the entire circuit and managed to turn it off.
- Ahh!
Realizing the danger they were in, the professor, Bart and Bert once again left the city for some time. However, once again they would have been forgiven, when people realized that it was not really their fault.
At home, Tubald tried to take the horrible taste out of his mouth, drinking a lot of water, coughing, and when he finally calmed down, he said angrily to Ginevra:
- They must be punished! My revenge will be terrible! - And it was. In the story "Tubald Weathercock’s Revenge", we will tell you what the poor musician did to avenge his luck.
The square was in a pitiful state. The desolate mayor commented with an advisor the next day:
- Even the statue of our dear founder, Lemonion Pluckwood, got dirty with the sewer jets! The opposition will take advantage of this, there are no doubts!
- They already have begun! - said the advisor, throwing on the mayor’s table the newspaper of the day.
On the first page a cartoon showed the statue of Lemonion Pluckwood, who instead of pointing west with his right hand had a microcontroller chip between his fingers, while on the other hand, which was originally inserted in his pocket, at the well-drawn caricature of the newspaper was holding his nose, protecting himself from the bad smell.
The mayor had only one word to express his displeasure:
- Fuckers!
