Act I

This was the first time that he thoroughly felt and believed himself to be a knight-errant in reality and not merely in fancy, now that he saw himself treated in the same way as he had read of such knights being treated in days of yore. Miguel de Cervantes, Don Quixote.

Romanticist

Winter is a wonderful time, you do not expect anything unusual from the winter, and when pleasant events do happen, they happen unexpectedly, that make they seem even better than they really are. From the spring, you wait for miracles, and when you get ordinary things instead, there is no limit to disappointment.

Stranger, the hero of today's narrative was sitting in his chair and talking about the past glorious times. Five years ago, in 2013, he took part in the battle held in the Silicon Duchy the distant land. Despite the fact that our hero did not win the victory in that fight, it was the battle that was the first in a series of events that made that spring special.

And now, years later, Stranger again had a desire to experience those feelings, and perhaps make a new leap in life. He again writes a letter to the Duke, but without the hope of an invitation.

A few days later, the mail pigeon arrives suddenly from the Duke and brings glad tidings from distant lands! Stranger is invited to a new battle!

With a restrained joy, characteristic to him, Stranger sharpens the soldering iron, puts on antistatic chain armor and pushes toward his computer. The battle is going to be glorious!

Pragmatist

Having received the opportunity to once again participate in the contest held by Element14, Stranger (romanticist believes that this name sounds more poetic than the original, though we will not argue with him) decided to draw up a plan in advance that he can not fail to fulfill. The fact is that at his disposal there was a sufficiently large number of various components, which for one reason or another had not been used before. For the Smart exercise bike computer project, which was announced for the competition, there were:

• Atemi exercise bike, which has a reed sensor of pedals position;
• Arduino DUE board, recovered after one of the earliest projects;
• Nucleo-F303RE and Nucleo-F722ZE boards
• FRDM-K64FFRDM-K64F board remaining after one of RoadTests;
• bluetooth module HC-06;

Thus, Stranger initially had a complete set of parts necessary to complete the project. And as it turned out later, such preliminary preparation helped him very much.

Demiurge

If a person gets what he wants, he will very quickly fall into melancholy, for it is in overcoming difficulties that people find happiness. So it turns out that evil ultimately serves good, because if there was no evil, it would be impossible to know the good.

It seems that a person from a distant and cold country wants to participate in the contest from Element14? It will be the greatest crime if not to try to complicate his life by creating from nothing different difficulties. How about breaking the postal service to begin with?

Scientist

Having ordered all the necessary positions in Farnell, Stranger began to work on the preliminary stage of the project: over the mathematical formulas necessary for the bike computer.

Everything was going well, Stranger quickly understood the principle of speed measurement, which is used in its Atemi bike, and then derived a system of equations describing the work of the exercise bike.

The only complication of the project at this stage was the determination of the torque on the pedal assembly shaft. The problem was solved in a fairly simple way, but the results of the experiments seemed contradictory to Stranger. Our hero began to feel the torture of conscience: to fit "a little" the results of measurements to the theory or to indicate in the blog honest, truly scientific data. As a result, scientific honor triumphed and the article provided true data indicating that the results were obtained by a deliberately simplified method.

Act II

"But I don't want comfort. I want God, I want poetry, I want real danger, I want freedom, I want goodness, I want sin". "In fact", said Mustapha Mond, "you're claiming the right to be unhappy". Aldous Huxley, Brave New World.

Romanticist

The fourth week of our epic battle came, but our hero had a problem in which the evil giants were clearly to blame: the Stranger does not have [the sword] using which he must fight! Probably the wagon that was carrying all the ammunition to him fell into the crevice between the rocks. But such a trifle can not embarrass our Stranger in any way, on the contrary, he is even glad of the difficulties, because it was to overcome them that he went to the duel!

Our hero took with him a glorious sword  FRDM-K64FFRDM-K64F with the aid of which he once already struck down a host of giants For the first time Strainger chose to fight using it

While the Duke, danzima was looking for the missing wagon, Stranger rushed into the next attack: this time he managed to overcome the magical obstacles that appeared before him and finally revive by methods of necromancy the Smart exercise bike computer! This glorious victory is described in the annals and undoubtedly deserves attention!

Scientist

While the parcel destined for Stranger was stuck somewhere in the logistical labyrinth, there was enough time for research! In the plan Maximum, two very interesting points were identified, and it was within these two weeks that our hero had to realize them.

The first experiment was the production of electricity due to muscle strength. Stranger was able to install a small electric DC machine on the exercise bike. Unfortunately, the power of the generator turned out to be relatively small and later this idea was abandoned. However, in science, such cases often occur when the work done leads to a negative result. Having read shortly before this experiment, a R. Feynman's book, Stranger decided to publish the results of the experiment, because failure is also a result.

The second experiment went much better: it was to install a tension sensor on the exercise bike. The sensor is a potentiometer, connected through a traction system to the tension changing mechanism of the exercise bike. The experiment was completed successfully, for this reason, this sensor remained in the final design of the Smart exercise bike computer.

Pragmatist

Experiments are certainly good thing, but the goal that Stranger had set before him was to fulfill the plan Minimum. Even without having any components from Farnell, Stranger, as mentioned above, could still build a full-fledged bike computer.

For one week an LCD display was connected to  FRDM-KW41ZFRDM-KW41Z and the possibility of outputting information about training was realized

An another week later, the computer was already in a fully operational state, all the main functions of the computer were implemented, as well as a set of special smart functions that Stranger uses during his training sessions.

Perhaps the reader is wondering what a typical Stranger’s training looks like. Here’s the answer to this question.

The first 20 minutes he goes at a low speed, sufficient to warm up muscles, then for a long time, and sometimes while the whole training (80-100 min), he goes at a normal rhythm. Here the most important thing is not to slow down, because you get used very quickly to a low speed and it will be quite difficult to return then to the previous tempo.

Sometimes Stranger prefers cyclic training: 20 seconds of slow riding, and then 20 seconds of fast riding, this rhythm is suitable when our hero does not have enough free time for full training. Another way to shorten the training time is to accelerate strongly on the last "leg", passing it (last 10 km) at the limit of physical abilities, but after such intensive training you can not stop immediately, you need to walk around the house for a while, otherwise the next day, it will be impossible purely physically to perform a regular exercise.

The problem with the above "smart" trainings is the need to constantly monitor the average speed, which is difficult to do with just a watch and a speedometer, so adding smart screens (called AST) has completely solved this problem!

Demiurge

To show people their insignificance and at the same time the omnipotence of random events is a great way to make them feel like they are not a god's but just a sinner. The sequence of random events has not yet allowed Stranger to get the necessary parts needed for the contest, but there is no reason to delay their sending any more – let him finish his project.

Act III

They raced down Up-Mile Hill together; the playing cards roared. Bill’s feet found the pedals again and he began to pump, wanting to go even faster, wanting to reach some hypothetical speed–not of sound but of memory–and crash through the pain barrier. He raced on, bent over his handlebars; he raced to beat the devil. Stephen King, It.

Pragmatist

Suddenly (although quite natural) Stranger received his parcel with  FRDM-KW41ZFRDM-KW41Z and what was his surprise when he found in the box two boards simultaneously! Then the idea came to him: what about using one board to work with Bluetooth, and the second one with all the other components of the bike computer? Thanks to this idea, it was possible to greatly reduce the development time firmware and in just one week Stranger was able to equip his bike computer with Bluetooth functions provided by the GATT CSC protocol.

Demiurge

Stranger was too much proud of his ingenuity! It is necessary to moderate his ardor, otherwise he will not even be able to win the contest. He still has not received half of the components ordered by him? That's nice, we should make efforts to ensure that he never receives them, but that's not enough: we need to charge him with work, so that he simply does not have enough time to complete the project.

Romanticist

A strange thing is going on around, a lot of things are hampering our Stranger in his glorious battle, just like some evil wizard is hindering him! But our hero has a secret weapon – a vacation! It will undoubtedly help him complete this fight, with honor and dignity! To this last battle is dedicated a separate chapter of the chronicle, that the benevolent reader has probably already read and knows that the battle (or rather the race with time) is finally over and now our Stranger is at an easy pace waiting for results of the fight.

And while he waits, we will tell the reader what is this Smart exercise bike computer and how did it happen that this wonderful thing became a symbol of our hero's new adventures?

In the summer of 2015, Stranger, resting in the residence of one earl, was surprised to find himself in a very bad physical condition, no entertainment that required physical strength and endurance included in the program of the evening was of success to him. A magical artifact called scales helped to identify the problem. Stranger weighed 105 kg, which for his height of 183 cm and for a relatively young age exceeded any common sense!

Back home, Stranger was determined to change something in his life. Nearby, the famous stallion Rossinante was grazed, whose horseback trips our hero has neglected for many years. Stranger decided to ride on Rossinante every day, in order to come in good physical shape. As time went by, the trips made their effect and the Stranger's weight dropped to 85 kg, but horseback riding quickly bored our hero.

One day, when Stranger was already thinking about stopping his trips, he met one worthy lady, inadvertently mentioning the amazing of her strange talking books.

Prior to this moment, Stranger, read only literature devoted to alchemy and magnetism, but the proposal of the lady still did not leave his head: what is an audiobooks? Maybe listening to them instead of the usual and already pretty annoying music while traveling will bring more pleasure?

The first author, whose work Stranger decided to listen was Isaac Asimov. The most memorable book for him became The Naked Sun, after which Stranger fell in love with literary fiction and to date listened to about 500 literary works riding on Rossinante’s horseback, including all those quoted in this story.

Many happy moments in life of our hero are now associated with books, but last time such moments have become a rarity. Nevertheless, life is cyclical and a similar period of decadance was in Stranger’s life in 2013, when he was strongly encouraged by the Smart life challenge. Therefore, the author of these lines hopes that Smart exercise bike computer will be the beginning of a new cycle in the life of Stranger, a cycle better than all the previous ones.

The final conclusion

The project is finished and all the stories are told, what is the result? Let us recall what our hero's plan was and briefly discuss what we managed to do in these 11 weeks.

There was a completely, carefully executed plan Minimum, in addition, there were fulfilled certain points from the plan Maximum:

• an additional tension sensor added;
• experience provided in generating electricity by rider’s muscle strength;
• realized charging the smartphone from the bike computer.

An attentive reader will probably ask, but how was the charging of the smartphone realized, since the experience with the generator turned out to be unsuccessful? It's very simple: thanks to the sandwich of two  FRDM-KW41ZFRDM-KW41Z the bike computer has not 1 but 2 USB ports the first one is connected to a charger or PowerBank and to the second one you can connect a smartphone for subsequent charging The solution does not look as elegant as wireless charging however as it turned out Stranger’s smartphone does not have this function(wireless charging and even implemented in the project it would not be possible to test it

Neither a computer program nor a program for the smartphone were written, but this, as it turned out, was not needed: the received device (shown in photo at the beginning) has a standard Bluetooth protocol GATT CSC, which is supported by many mobile applications, which in turn can transfer data about training to a personal computer. This, by the way, was the reason why the computer does not have a pulse sensor installed – it is easy to connect such a sensor to the phone (for example, available at Stranger Xiaomi Mi-band 2) and use it together with a bike computer.

The only function that our hero did not have time to implement and regrets about it (note – this function was included in the list of options) is the function of automatic turning on / off audio on the smartphone. With this function, Stranger could go deeper into the world of literature, like the hero of one of Stephen King's works. However, let the benevolent reader cast aside doubts  – once, on a wonderful day this function will be realized!