If you are just a beginner in electronics or just started learning Arduino – it is easy to get lost among hundreds of boards, electronics parts, and tutorials. You may already have an Arduino board to play with but still feel that there is no fun in learning as you need to search for suitable external parts and look for guides on how to solve specific problems. We can all agree that learning new things in a systematic and organized way gives maximum benefit. One of the easiest ways of learning electronics and programming microcontrollers is to start with Arduino. It is an open-source board that comes along with the development platform (IDE), where you can start writing and executing programs right away. Despite its simple look, Arduino is a very powerful microcomputer capable of performing different complex tasks. It may read a wide range of sensors, process data, and output results to displays and LEDs, run motors and servos. The limit is only your imagination. The maker communities on the internet already have built millions of projects around Arduino. There are many types of Arduino boards available for different purposes. They come in various sizes featuring different processors and…
Medical equipment is expensive and not always accessible to a wide audience. In fact, in any biomedical measuring instrument there is nothing extraordinary – here you can find ADC, analog front-end with low noise op-amp, some controller. But the central part what makes it different from consumer electronics is safety. Because device is connected to your body through some sort of electrodes, there is always a risk of electric shock. So power supply has to be isolated if it is powered from mains. There might be other additional safety circuitry to prevent possible hazard. And of course there are many safety regulations and certificates to overcome before device can be used with patients. This is where main cost comes from. It doesn’t mean that you cannot experiment with your body signals. You only need to know what are you doing. If you are building your circuit to acquire bio-signals, be sure to use a proper isolated power supply, even better – go with battery power. Once said, let’s look at great development of Arduino shield to be used for acquiring various bio-signals from your body.
Ultrasonic echolocation is common practice in many areas including nature itself. We all know how bats or dolphins navigate – they emit ultrasonic waves and depending on the time delay of reflected echoes, they can determine the distance from obstacles or catch. From an engineering perspective it is relatively easy to measure distances with ultrasound – all you need to know is sound speed in the air and time delay between sent and received pulses. L is the measured distance; CAIR – ultrasound speed; t – the time between transmitted and received pulses. The accuracy of measured distance mainly depends on air temperature. The following formula can calculate sound speed in the air approximately : For instance, at 25ºC the speed of sound in dry air CAIR = 346.13 m/s. If you want greater accuracy, you should also measure temperature to adjust sound speed.
Arduino is a great platform for fast prototyping and building projects. But probably one of the best things here is, that Arduino layout allows plugging hundreds of standard shields. Today you can probably find any type of sensors, displays, drivers included in to shields. This is where comes the real power of using Arduino. Gearbest have supplied us with a great combination of commonly available products including Arduino Mega2560 and LCD keypad shield. Arduino Mega2560 comes with powerful AVR ATmega2560 microcontroller featuring 54 I/Os, 256KB flash, 4KB of SRAM and 4KB of EEPROM. It has standard Arduino header layout extended with tens of additional that are not occupied by shields. They can be successfully used with additional gear.
Previously we have driven servo and DC motor using an Arduino motor shield. It is easy to interface these motors and write the code. This time we get to the stepper motor control and discover the full potential of the motor shield. Stepper motors are more complex devices than servos or DC and require some knowledge before running them. You cannot expect to plug some voltage and see it spinning. Their primary purpose is precise stepping that gives control of how much the motor is turning. You can find a stepper motor in any printer which feeds paper incrementally – and this is where you can get one. Disk drives are another great source to scavenge. We will not get into stepper motor working theory. Do your research before trying to run one.
It’s been over three months since the solar collector was installed. I decided to build a controller by myself. And it turned out that it stayed in the prototype stage. So I put it into the enclosure and left it like is. So far, it works fine – water is hot every day, so I have nothing more to expect. I did not capture enough pictures of the build, but I think I will share what I have. In the forum thread, you probably saw what type of system I was building. As I mentioned, the solar collector is cheaply made in China and is pressureless. They usually come with a unique controller which takes care of the refilling tank, ensuring protection from water freezing and other individual scheduled routines. A pressureless collector usually is first filled with water which heats, and then it is used (mixed with cold). The initial test shows that when the collector is in direct sun, it boils what leads to heater elements’ calcification. Overall lifetime reduces and so efficiency.
Probably you have noticed that Arduino is spread worldwide. It would be ridiculous to see one manufacturer producing them. The Arduino group produces an original board that is named Arduino. This is their trademark. But being an open-source product, Arduino has become popular in almost all workshops, so demand is enormous. Since building plans are public, other electronics manufacturers started building Arduino-compatible boards. These are the same Arduino boards but with Arduino’s name and logo removed. It is 100% compatible with standard Arduino that works with software tools, extensions, and modules.
Among my electronics junk, I found a VFD (Vacuum Fluorescent Display) display and wanted to make sure it still works and can be used in projects. It’s a 16T202DA1E display manufactured by Samsung. It can replace the standard HD44780 based liquid crystal display out of the box. First of all, it only requires a 5V supply. The voltage step-up circuit for lighting fluorescent display is already on board. The controller accepts the same commands as any 2×16 LCD does. The pin-out of the display is as follows:
Recently I’ve got an Arduino LCD keypad shield. I haven’t decided yet where it will be used. But why not plug it into an Arduino board and see it working. The shield was initially introduced by DFRobot, who has some cool open-source stuff, including robotics-related. This LCD keypad shield is a cheap and convenient solution for adding 2×16 LCD and five push buttons (+1 reset) to Arduino design. LCD here is interfaced using 4-bit mode and occupies 4 (D4), 5 (D5), 6(D6), 7(D7), 8(RS), 9(E), and ten digital pins. Pin 10 is used to control the LCD backlight through the transistor key. All five buttons are connected to a single Analog pin 0 using a resistor-based voltage divider. This lets us keep other pins for general use. The shield is designed to work with 5V based boards.
LDR (Light Dependent Resistor) is a simple, cheap electronic device. Simply speaking, this is a resistor in which resistance varies depending on light intensity. You’ve probably seen typical LDR in some projects where light intensity has to be taken into account. They can be used to activate light switches, alarms, adjust display brightness, and more. Light-dependent resistors can be different types. They vary in light-sensitive material used. Visible spectrum LDR is made using Cadmium Sulphide (CdS) or Cadmium Selenide (CdSe). This material is sensitive to the wavelength range from 400nm – 850nm. For the near-infrared spectrum (1μm – 3μm) there are PbS or PbSe materials used. For deeper infrared range (3μm – 1000μm) there are InSb and InAs.