What an Arduino is and what it can be used for?

It is a printed circuit board built around a controller chip. The chip itself can be programmed depending on what we want to use it to. The big think is that one does not require advance programming skills, it is easy to learn the commans. One can find a lot of help on the internet. The chip can be programmed from a computer through the USB cable. The board has a led and more analog in and output connectors.

What can it be used for? Your fantasy is the limit. I used it for the following so far:

-flashing the led programatically
-measuring temperature
-measuring voltage
-battery capacity measurement

It sends the measured data immideately to the computer on the USB cable, or it can save the data in its memory. If we connect an LCD screen to it, then it can show the data itself. It can be run on battery or from the power from the USB cable or from a power supply.

Of course different projects require different other stuff to be bought. For instance the sensors which data we want to use. One could control a relay depending on the data from the sensors, which for instance would control a lamp connected to the mains power. You can buy so called "shields" to it which expands its capabilities. Wifi shield, bluetooth shiled, SD card shield, sound module, lcd screen. You can connect RF modules to it, you can build an alarm system. You can buy a GPS shield or a GSM shield. These are only some examples.

I have bought mine on 2010.01.07. for 27,51 USD (today it would worth 29,89 USD counting inflation). It can be bought much cheaper today, you can find one for 3,5 USD including shipping from China.

Who have created this wonderful thing? The whole story can be found here. In short, an Italian joungster with his partners has created its prototype back in 2003. Its name was not Arduino back then but it was called "Wiring". Then later there are more threads in the story, who used who's invention, why he used it later, what company he founded. There were quarrels as well as we would imagine. The board was called "Arduino" from 2005. They say, that the name came from a bar where the creators were hanging by at that time. This may be an urban legend.

Anyone can build such a board, they have shared its schematics. Its website is: www.arduino.cc.

Cheap standing fan from Asia - It is a disaster, terrible, unspeakable, but it works

Hungarian version.

We have bought this standing fan around 10 years ago. It was not used too much, only on some summers if there was too hot. Unfortunately the summers are getting hotter and hotter in each year. If I remember correctly we bought it on a street market. The street markets sell cheap stuff without a store usually on open spaces. It get tired as the years passed by, of course it was not perfect even when it was new. I have found its blade on the street, because my blade has broken when I accidentally pushed it on the floor. Originally it had blue blades.

Its Brand is Crown, the size is 16 inch, which is correct.

It says: design in Taiwan. It does not matter where it was manufactured... It even has a model number: SF-101. The 60W is true. Q.C. Pass. It means it has passed the quality check. It depends what we call quality and what are the requirements. I think the inspectors either have not inspected this model or it is really what they call desired quality. Does it work or not? It is, so it passed.

I have put some paper under the motor as it resonates so that the whole fan resonates loudly.

Its power consumption:
1. setting: 43W
2. setting: 53W
Afterburner: 61W

Let's see what is wrong with it. The language is Hungarian but the obvious is visible anyway.

I planned to reinforce the legs so it would wobble this much. I have begun to take it apart. This is the sight I saw. It is one thing what would the consumer protection agency say about this, but this also bothers me. This is ridiculous. The incoming two cable, earth and phase are barely touches the pad where they should be securely soldered. They are held there by a feather. If the device falls to the floor for example, these wires can come loose and cause a short circuit. In a better case it only shuts off the fuse in the house in worse case it may catch fire. Horrible.

There is the hole for the wire to solder to, but the factory worker only barely soldered it there. Of course I understand that a factory worker in China solders 5000 from these a day in 14 hour a day for very little money. But anyway...

This is an unhappy standing fan, showing its internal organs.

This crack appeared from the normal usage of the fan.

This capacitor is a mystery. It is broken when the worker secured it, because there was not enough space between the housing and the capacitor, so when the worker tightened it broke down.

As I have seen more and more from the design details, I knew that it is unnecessary to reinforce the legs, as the problem does not lay there. The problem is that the fan blade is not in balance. Because of this, the faster it spins, the more it wobbles. So it does not matter if I reinforce its case or not, sooner or later it would become loose again. So I decided to leave it as it is. I have changed the capacitor, I soldered the wires back and tightened the screws. It stays as it is. On the first setting it does not wobble that much, you should not use the others. :)

I ordered the capacitor from China, it was cheaper with delivery than in a shop in Hungary. It cost 99 USD cents.

I have secured it as it should have been in the factory, I have soldered the wires again.

I have soldered the main cables again and cleaned the button contacts.

I have assembled it again and now it looks the same, works the same... Of course it wobbles less with 10% and will not catch fire. But the main thing is that it works. Please do not buy such a cheap standing fan, there are much better fans for a little more money. Unfortunately I do not remember how much it cost when we bought it.

3.part- Fail of the week - 6600 mAh genuine HP laptop battery teardown

Hungarian version.

To have more 18650 cells, I thought to buy a used laptop battery and get the cells out. It turned out it was not a good idea. However it seemed to be a good offer. For 7 USD a used HP 12 cell laptop battery. I thought that it is not a recent model, but I have not expected this. It arrived with the post, it is a very massive and heavy piece.

It contains Sony cells, great!

Between the picture above and below after more than an hour suffering I was able to open it. It was built from almost a 1mm thick plastic and glued or melted together very well. I even had to use a chisel to open it. This was inside, I like the cell color.

There was no indication about the manufacture date on the outside, however there are signs inside. 2002 or 2003. Oh, no. It may be 13 years old?

The manufacturer put two thermistors into the battery, very clever. One is in the intersection of the left four cells, the other is on the lower four cell. It is better than in the other ones I opened, where only one thermistor was glued to one cell.

I have numbered the cells, so I will know which was where.

Controlling circuit:

The usual heat fuse and two chips which are anonimized.

But here we go! Let's measure the voltage. The three on the right had 2,27V, the other three packs had 1,73V... So I will not be able to use them for security reasons. If the voltage of a li-ion cell falls below 2,5V the inner chemistry gets damaged. The identification codes on the cells tell that they were manufactured in 2003. They are 13 years old! How can this be still around? And who would pay anything for this? I do. But you can't win them all, this buy was a failure. I cut off the two thermistors, so I have now 4 of them. I will take these cells to the recycling center where they already should be for 10 years. I do not wish to open such batteries, it was so hard and I won nothing, but experience.

Overview about the consumer battery types

Hungarian version.

AA and AAA Ni-Cd Nikkel-Kadmium battery:

This type was invented in 1898, it was famous until the 1990s when the Ni-Mh became more popular.
1,2V is its nominal voltage, it can only be used limited instead of the normal not rechargeable batteries with 1,5V voltage. They can withstand high current drains. Their capacity is not too big, I do not have good experiences with this type of batteries. They are inclinable to a so called memory effect. If these batteries were not charged fully for a couple of times, then at the next recharge the full capacity became lower. The Cadmium inside them is highly toxic, the European Union has already limited their market.

AA and AAA Ni-Mh Nikkel-metal-hidrid battery:

Their research began in 1967 and they are still popular today, but the manufacturers use Li-ion in more and more places recently instead. Ni-Mh capacity is more than Ni-Cd, they also have 1,2V nominal voltage. They cannot withstand that high drain current as the Ni-Cds. They are not likely to have memory effect. They are also used today in hybrid and full electric cars.

For both the mentioned battery types the electrical devices do not have an easy task to measure the remaining capacity for them. It made me nervous that after recharge I put the Ni-Mh batteries into my camera and it showed after some picture that the battery is now only half full. And as the time went by after 50% capacity the camera said the batteries will be discharged soon. Now I know why this happens. This is in connection with the voltage while they are discharging, which can be followed on the following picture:

On the left is the voltage in mV, on the bottom are the seconds while I was discharging a Ni-Mh AAA battery. It can be very nicely seen that the voltage does not drop consistently like with the not rechargeable batteries, instead in the beginning the voltage drops to 1,2V then it stays there for a long time, and at the end it suddenly drops under 1V. That is why the current capacity cannot be measured accurately by the devices.

They are very irritating at charging as well. There are so called dull chargers for them, which charge them with a small constant current, not watching the voltage in the meantime. They may also overcharge the batteries. On the other hand there are the smart chargers. I do not like them either. Recently the batteries were discharged in my camera and I have put them in the smart charger. One of them was charged for 6 hours, the other was "full" after 10 minutes, however it was empty! I had to discharge it under 1V so the smart charger would recharge it fully. They are a mess.

Li-Ion batteries:

they have begun to develop this type in the 1970s. They went out to the consumer market in 1991 first. They have a much greater power density, they are much lighter than the previous types. They are the stars of the today’s mobile world, they are used everywhere. They are even using them in electric cars.

Their nominal voltage is 3,6-7V. Their voltage drops consistently while discharging so it can easily be measured how much power they have left. They do not have a memory effect, however they cannot be recharged that much like the older types. They are much more sensitive than the others as well. Unfortunately today they can even also be dangerous.

If they get shorted because of some reason, which can be an outside effect or a manufacturing error, they can get hot very fast and a so called "thermal runaway" may begin. This means a sudden overheating which induces a chain reaction inside the cell which can cause an explosion if the battery has a closed sealing package. For instance the 18650 Li-ion cells which are used in the laptop batteries are made in this way. If a cell gets overheated and starts to burn, it will very likely get the other cells to overheat as well. One has to be careful not to leave for example devices with li-ion batteries on the sun or in the car. Their transportation was already limited on the planes because of the fire hazard.

They must not get discharged under a certain voltage (around 3V), because it damages the chemistry inside. They must not get overcharged over the set voltage, as they can overhear and damage the cells. They are very fragile. But there is no better alternative today instead of them. The researches are ongoing to find a safer alternative.

The Li-Po batteries does not differ much from the Li-ion cells, mostly just in their name and the used Anode and Cathode materials. They may have different characteristics.

The recycling of the mentioned batteries is only feasible in huge quantities today, however in the future as the resources will begin to run out on earth, this trash will worth a fortune. After selection of the battery types they are grinded and then on high temperature they get melted and the metals separated then reused.

Opel Corsa C (Vauxhall Corsa C) outside temperature meter replacement

Hungarian version.

The outside temperature sensor got broken in a 2002 Opel Corsa C with left side steering wheel. It first showed wrong amounts, then it just gave two lines as it can be seen on the picture.

The replacement procedure can be followed on the following video:

The sensor can be found in front of the car in the bumper secured with some plastic clips. You can push the sensor inside with the help of a screwdriver from the outside, then the sensor can be unclipped from its cable connection. You can get to it from the top, I have thin hands, but it may be easier from under the car.

It is strange that the cable harness goes on the left side of the car to the front, then from there a cable goes to the right just to connect the temperature sensor. I do not understand this, why have not they put the sensor to the left, so they could have saved money on cable and connections as well. Maybe a car with more extra equipment has something else connected here.

The sensor is a simple thermistor put into a plastic case:

The German quality is not as it used to be, it has broken in 14 years. :)

I do not know what cost 4,5 USD dollars on this. I think it was produced from 30 USD Cents. Of course the profit of the seller is in the 4,5 USD. Although the replacement sensor I bought is not a Siemens product, I hope it will last another 14 years. It only contains a thermistor inside the plastic case, which changes its resistance depending on the temperature. That is all it does.

This picture is from Wikipedia, owner: S 400 HYBRID

The first Opel was manufactured in 1899 in Germany. Opel became a share-limited company in 1929, United States-based General Motors took a majority stake in Opel that same year. General Motors assumed full control in 1931 and today Adam Opel AG is a wholly owned subsidiary of General Motors Company. The Opel Corsa C was manufactured between 2000-2006 in Europe. I think the 1.2 L engine is way too little, it does not have enough power for the car although it produces 75 horsepower. The inside is very durable and the body does not rust after 14 years.

I have already had to fix the dash panel on our car. It happened that while driving all the gauges and lights turned off on the dash panel. If I hit the dashboard with my hand, the gauges turned on again. It was obviously some kind of electrical conduct problem. I had to take out the gauge panel from the dashboard. On its back there was a very bad quality connector which caused the problem. It is so terribly designed that I was shocked. I have put some WD40 contact liquid on the contacts and it is working since.

Skoda Fabia (an European car brand) hack

Hungarian version.

Once I owned a 2004 Skoda Fabia car. I have got from somewhere the factory service manuals for it. These does not only contain what kind of parts the car has and how to dismantle it, but also gives instructions to read out the main computer data and overwrite it with new values. This particular car was manufactured in the Chech Republic, after German licence, its main computer was built in Italy. This car is a result of a multinational cooperation.

I have ordered from an USB OBD2 diagnostic cable which can be used to connect the car with a computer. Most of the cars have this standard connector since 1996. The service stations are reading out the error codes from the car computers through this connector. I think the whole car control software can be updated as well, however I am not sure about this.

I have begun reading the manuals and I have found some interesting things. I just want to mention the most fascinating ones and the ones I have changed on the car. You are able to test the different parts, some of them have test sequences. For instance you can test the dash panel, it will move the gauges, you can calibrate the fuel gauge, you can turn on and off different relays on the engine, you can change the distance till the next service, and so on. You can change the strength of the power steering. If I wanted to get a sport setting I could have set the RS setting. If I wanted a setting for people with disabilities I could have set it. At the end of the day I have not changed this setting. You can query the data of the factory alarm system. When have it turned on, which sensor triggered the alarm. Was it the internal movement sensor or the trunk sensor? There was a setting what I changed, which controlled the alarm remote control reaction. I turned the option off which allowed the car to blink the turn signal and activate an alarm beep when I disabled the alarm. So now it only blinks the turn signal if I arm the alarm. If the car had parking sensors, you could query the measured distance behind the car and you can calibrate it. You can query the measured values of all the sensors in the car. And there are "millions". Engine speed, engine temperature, inside temperature, fuel level, position level of the electric accelerator pedal and so on. You can query every fault codes from every system on the car. Starting from the airbags, the heating system, the air conditioner, engine, to ABS. Everything. You can spend quite some fun time exploring these. Once I have logged the data of several sensors while driving and a laptop was connected to the car. I was able to collect and save the gathered data. I have changed the behavior of the door locks. I have turned on the function which automatically closes all the doors if the speed rises over 9 Miles per hour. The manual said that this is not activated on the Fabia type cars and it is not activated in the factory, but I have turned it on and it worked beautifully. I think this was only activated on VW cars. I have also activated the function which opened all the doors if I pulled the ignition key out of the socket. 

So with this blog post I just wanted to show that what kind of technology was in a 2004 car and how much can be overwritten or changed on its computer. I think the opportunities are much wider on the today’s cars. It is good in the VW group cars that the manuals are made with German precision and are very well documented. They also use the same standards inside the group brands. So a VW, a Seat, an Audi, or a Skoda has more in common inside than it seems from the outside.