Clever way of measuring defectiveness of cooling fans

Have you ever wandered how effective are cooling fans when compared to each other. Some of them are noisy, other quieter. But with more silence there comes a question – are they effective enough. Instead of probing with bare fingers, nop head decided build his own coolometer which would give some objective results. He surfed through various methods and instead of anemometer he decided to use a 12V 0.8W light bulb and measure the cooling effect – measure how fast bulb filament is cooled. Knowing that when bulb is cold, resistance is about 15 Ohms, when hot – resistance is ten times higher. He constructed Wheatstone bridge circuit where one resistor is replaced with bulb. To make it digital, he has chosen MicroView module which comes with Arduino and OLED 64×48 Lcd display. He soldered all components on prototyping board and put in to 3D printed enclosure with display, bulb sensor connector, power plug and control button. With his meter he was able to take pretty interesting measurements including cooling maps taken from cooling fan area with 2mm resolution. Continue reading

Wearable OLED display powered with attiny85

Wearable electronics is commonly used in many areas. We are not talking about professional stuff like medical devices, but more hobby corner. But who knows where is a limit. Today anyone can assemble wearable projects with cheap building blocks that are mostly based on Arduino. AwesomePCB have shared his instructable on how to build a wearable OLED display covered with leather frame that blends pretty well on fabric. He used small SSD1306 128×64 OLED display which is connected to small Attiny85 Arduino compatible board. Coin cell battery is enough to power it for quite some time. He paid some attention to details on how display is attached to leather piece and how this piece is snapped to clothes. You can do many fun stuff with the display including a temperature monitoring by attaching thermometer, it simply do rudimentary activity tracker with accelerometer or display current your mood with smileys which can be changed with single button press. Continue reading

Driving SSD1306 based OLED display with DMA library

People love using OLED displays in their projects because they offer better contrast, color depth and different feel from LCD. So there are plenty of OLED display modules ready to be used with microcontroller boards like Arduino. Adafruit also offers great 128×64 SSD1306 based OLED display which has great library for Arduino. But problem is that there are so many Arduino variations with different processor families that using one generic library doesn’t ensure its efficiency. So the guys from grav-corp decided to tweak the library so it would work with Arduino Due much faster because of DMA. Arduino Due is equipped with ARM microcontroller which most of the features aren’t used by standard Arduino library that are initially built for AVR micros. And so the LCD is driven with SPI interface which works well with DMA. With standard library calls to display() function took about 2ms, with new implementation speed quadrupled and speed could be increased even more by rising SPI clock speed. But another main advantage is that using DAM practically frees CPU from writing data to LCD. Once… Continue reading

Wrist watch size Enigma machine

If you are WWII enthusiast or simply interested in ciphers then take a look at this great project. Basically this is a replica of famous German Enigma coding machine which fits on a wrist. It is built around Arduino and can be controlled with three buttons. Information is visible in graphical OLED display. User interface is quite well thought and robust. Initially you need to know a bit about setting Enigma wheels to start encoding letters. Custom enclosure and straps looks really firm and durable. Continue reading

Simple OLED alarm clock with temperature feature

OLED displays have many benefits over regular LCDs. They have better better contrast. Because there are not back-light used, a deep black levels can be displayed. They have wider viewing angles and are more power efficient. Also are more lightweight what makes them attractive for using in hand-held devices. OLED displays are available in hobby market so everyone can use them for great projects and see the benefits. Df99 have shared his instructable where he builds pretty cool alarm clock with temperature display by using Arduino Micro and 128×64 OLED display based on SSD1306 controller. Clock function is implemented with DS3231 RTC IC which has Arduino library support. Clock has two push-buttons for clock setting. Temperature readings are done from RTC chip where sensor is used to compensate temperature drift. Continue reading

Universal RFToy for quick and easy interfacing Radio frequency modules

Radio modules are great for interfacing remote objects without need of wires. They are cheap and fairly easy to use. With Arduino things are even better as there are software libraries already ready for use. Rayshobby went even further. They designed a small board that incorporates Atmega328p with Arduino bootloader. 128X64 OLED display, coin cell battery, few navigation buttons and most importantly headers for plugging in various RF modules. In fact normally you would need two types of modules – nRF24L01 that comes with both receiver and transmitter, and two different four pin modules that work in 433/315Mhz frequencies. Each board works as standalone device that can be paired with other and so creating virtual wires. Few demos demonstrate how they can be used as RF recorder storing 7different signals or controlling 7 different devices. Another use is so popular wireless temperature sensor where remote sensor temperature can be displayed on receiver’s OLED display. Modules are also equipped with 3.5mm audio jack that gives ability to record and analyze RF raw RF signals wit software like Audacity. Continue reading