Andrianakis Haris informed us about his latest project. It’s a digital Thermostat for energy saving fireplaces. He writes:
In the need of my new homemade energy saving fireplace (which boils water for the radiator) i designed and built a digital thermostat. The idea to design my own thermostat came when i came across with the following problem.
When i first fire the fireplace the water in the boiler around the fireplace is cool. After a few minutes the fireplace warms the water enough so that the water temp exceeds the thermostat limit. The thermostat changes state and drives an electric valve to move the water from the fireplace boiler to the radiators. The electric valve is slow enough and takes a few minutes to make a full turn. While the water is moving from the fireplace boiler to the radiators, circularly cool water is coming back in the fireplace boiler from the radiators. Τhe water temp in the fireplace boiler is getting cooler and after a few minutes falls under thermostat’s limit. The thermostat changes state and stops the valve from driving the water to radiators. This happens again and again until the whole amount of water in the radiators is get warm.
Thermostat V1.0 for energy saving fireplaces - [Link]
pcmofo @ instructables.com writes:
I wanted to make an easy and secure way to enter my garage. RFID was the best way to unlock my door, even with my hands full I can unlock the door and push it open! I built a simple circuit with a basic ATMega 168 arduino chip and a ID-20 RFID reader to control an electronic door lock.
Arduino RFID Door Lock - [Link]
Scanalogic-2 PRO is a 4 channel Logic Analyzer and Digital Signal Generator priced at 59€. At this cost it’s easy for a hobbyist to get one and make digital circuits debugging a breeze. It’s designed to capture, decode and analyze serial protocols like SPI, I2C, UART, 1-WIRE and CAN in a few clicks. Data is captured on PC using the free and efficient ScanaStudio software.
- 20 Million Samples Per Second
- 4 Input/Output channels
- 256K Sample per channel
- 2V, 2.8V, 3.3V, 3.6V and 5V logic levels support
- Serial protocols decoders (SPI, I2C, 1-WIRE, UART, CAN, LIN,Manchester)
- Various trigger options
> Download features PDF
What you can do with Scanalogic 2
- Capture and Analyze signals – Serial protocols sampling, decoding, debugging (UART, I2C, SPI, CAN, 1-WIRE, LIN, Manchester,…)
- Save captured data and playback them later or on the other side of world!
- Generate PWM, FM or UART signals
- Capture images of your signals for demostration.
- Digital PWM and FM signals analysis (FFT)
- Compare captured signals.
- Use “mixed” mode to play a signal and record response on another channel (at the same time!)
- Generate your own data (PWM, FM, Serial Data)
- ScanaStudio PC software offers smooth scrolling and navigation options.
I came across this neat bluetooth module called HC-06. It can be found as cheap as $6 on ebay, and gives you convenient UART access to bluetooth wireless capabilities.
My 3yr old has this home-made LED clock in his room. I thought it was time for an upgrade since the clock was very minimalistic. Its only function was to keep track of time and display it on the LED panel. And considering it was my first “completed” project with avr (atmega168), I thought I could make it better this time around.
LED Display Over Bluetooth With Android - [Link]
Would be interesting if we could make our microcontroller to sing for us not just beeping or blinking; this project is all about using the powerful AVR ATmega168 16-bit PWM feature to produce accurate musical notes such as playing the child’s favorite Twinkle-Twinkle Little Star song or we could say beeping with style. The principal we learned here could be applied to other AVR microcontroller families that support 16-bit PWM.
AVR Twinkle Twinkle Using PWM Project – [Link]
AdaFruit recently released a sweet little TFT display that I was dying to hook up to a netduino: the display features a resolution of 128*160 pixels, is capable of showing 18-bit colors and has a microSD card reader on the back of the breakout board. As usual, Limor wrote a nicely detailed Arduino tutorial showing how to connect the display and how to write sketches to drive it.
The Arduino driver relies on the ability of the Atmega168/368 to toggle digital lines extremely fast, which does not work well on the netduino due to the latency introduced by the .Net Micro Framework: even when configured to use hardware SPI, the Arduino driver constantly toggles a data/command output line, rspin below, which would be unbearably slow on the netduino if the same method were applied.
The netduino has one advantage over the Arduino: it has plenty of RAM. So, instead of toggling I/O lines slowly all the time and using next to zero RAM, the netduino driver allocates a 40K buffer corresponding to the resolution of the display in 12-bit depth colors (16 bits per pixel) and leaves the ST7735 in ‘data’ mode upon initialization.
Drawing always happens on the internal buffer first. Then, whenever the actual display needs refreshing, the display I/O operations are performed using hardware SPI, blasting the entire 40K buffer. It may sound crazy but using this method on the netduino is faster than refreshing a single pixel while toggling an I/O line!
Driving an Adafruit TFT Display with a Netduino – [Link]
IgorPlugUDP is an ethernet-enabled infrared receiver. This is an old hack that kmmankad brought up in the forum.
What makes it really cool is that the ethernet is bitbanged using nothing but the bare pins of an ATMEGA168. It is transmit-only, it cannot receive network packets, but that’s enough for a lot of projects. [via]
Networked infrared remote control receiver – [Link]
Some time previous to getting my ham license, I was at a friends house who showed me an LC (inductance) meter built from a kit. It was based on a PIC16C22A, and I certainly do like the PIC mcu’s, but decided I would embark on the task of re-engineering my own that uses an Atmel AVR chip, the Atmega168. It’s been a journey. Also, I am giving away for free the schematics, firmware, and source code as open source under the GPL.
Inductance meter - [Link]
BrianH has posted a useful Instructables project that tests the capacity of rechargeable NiMh and NiCd batteries. The circuit is based on an Atmega168, and functions by draining the AA batteries (from 1 to 3 batteries) then computes and reports the capacity in mAh. It uses a Nokia 5510 graphic LCD to report battery condition and three MOSFETs used to switch the resistive load on and off during testing.
Capacity tester for rechargeable batteries – [Link]