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Attiny10 touch button utilizes intelligent RGB LEDs

Attiny10 touch button

This is rather interesting touch button based on Attiny10 microcontroller. First of all Attiny10 is 6-pin microcontroller suitable for tiny applications and fit nicely in this touch button project. Second thing is that it features ADC input what makes it easy to implement touch sensing. With TinyTouchLib it becomes way easier. Second part in this project is four fully programmable RGB LEDs. Since Attiny10 has only three pins left, it needed smart LEDs to be used. There are four WS2812 smart LEDs used that require only single pin to be controlled. All LEDs are connected in cascade mode where 24-bit composition data can be sent in series. Each led is capable to produce 16777216 colors. Again, LEDs are controlled using light_ws2812 library what makes things simple. The project and libraries are produced by cpldcpu used in github. Continue reading

Playing with voltage controlled oscillator based on Attiny25

voltage controlled oscillator based on Attiny25

Alex wanted to see frequency impact on different components. First of all he built a voltage controlled oscillator using couple of op amps. But he wanted something simpler and more digital. For next step he took Attiny25 microcontroller which comes with internal PLL for fast peripheral clock. It enables to generate high frequencies that drive MCU peripherals like timers while system clock remains intact. Using timer compare on match method he was able to generate 32MHz clock signal on pin. Since the idea was to have voltage controlled oscillator, he added potentiometer to ADC input. By reading its value microcontroller determines the frequency. By underclocking or overclocking MCU frequency ranges from like 128kHz to 32MHz in fairly large steps. Alex made few interesting experiments on how noise is picked up on breadboard depending on wire placing. This gives clear idea how this impacts the results if you are designing sensitive projects. Anyway this experiment is a great tutorial on using PLL as clock source for peripherals on Attiny25.   Continue reading

Interfacing MMA7361 accelerometer to Arduino

Accelerometers are found in many devices even smart phones. They are cheap but plays significant role where motion, acceleration or inertial position detection is involved. You can get XYZ accelerometer module for like $3 from eBay. Alex made a post about his experimets with MMA7361 accelerometer model. Luckily there is an Arduino library that makes programming even easier. Practically there isn’t much about reading values – simple analog read does the business. After small experiments Alex built acceleration activated LED blinking box. He even managed to place the circuit inside dental floss container. Instead of trying to squeeze Arduino in it, he’s chosen smaller micro – Attiny45 which fits nicely. It is powered from 3V coin cell battery. Just a nice quick project for an evening. Continue reading

Outside thermometer based on Attiny2313

attiny2313 DS18S20 thermometer

Today modern cars are equipped with outside and inside thermometers. But some older ones are missing this feature. Sometimes it is good to know what temperature is outside while driving. You can stick one of those gadgets on your windshield. But why buy, if you are capable of building a decent thermometer using small micro. Check out this thermometer based on DS18S20. Attiny2313 microcontroller does the reading of temperature value and displays it on LCD. Since thermometer is gonna be used in the car. Special care is taken when designing power supply part. It’s a noisy environment where voltages can spike up to 40V. An LM2574 regulator is used with inductive and cap filtering to get stable 5V supply. Original design was intended to be used in Dacia Duster. Bright LCD nicely fits in free space on panel. Continue reading

AVR programmer is small as finger tip

small vusbisp programmer

I don’t know if very tiny tools like programmer adapters are very handy to use, but it is always fun to watch how tiny they can get. Philip took a vusbtiny programmer and squeeze it in to smallest PCB he could make. So, he made USB connector directly on PCB by tracing pads on it. But to be sure, on other side he made footprint for Mini USB socket. If one fails there is a way out. Of course all parts are SMD except the 6-pin ISP connector. The board size come to be 12mm x 28mm and I think, there still is a space to squeeze a bit by making ISP header smaller (use 1mm instead of 2.54mm) or choosing smaller passives instead of 0805. But would such tool be normally useable? Continue reading

Attiny13 based RFID reader

Attiny13 based RFID reader

RFID readers aren’t very expensive to buy. But if you are real hobbyist and like building instead of purchasing stuff, then Attiny13 based RFID reader might be interesting to experiment with. It was build by Vassilis Serasidis – author of many great projects. As always he tries to keep things simple, cheap and easy to follow. The RFID reader he builds works with standard 125kHz tags that uses EM4100 protocol. There is a good explanation on how the circuit works in physical level. It includes how reader transmits data and receives from passive tag. Reader is assembled on prototyping board using through hole components and hand made coil on the back. You will also get some understanding how to calibrate coil to have great range and reliability. Currently reader outputs the 10-digit Tag serial number via Serial interface 2400 bps 8N1. Continue reading