OCT30
DIY hot air soldering station
For all those who are not able to afford themself a new SMD hot air soldering station, there is a pretty simple solution. By using heater, hair dryer, plastic bottle, some pipes and electronics you could make a hot air station that works just as well as the real one.
With little automation and smart electronics this could make a serious hot air soldering/desoldering station. There is another version of the same thing after the break and the build instructions are on the project page.
Source: Alfred73
OCT29
Hand held electrocardiogram (ECG) with ARM uC
Electrocardiogram is based on STMicroelectronics STM32 Primer development board which has onboard LCD, USB support and STM3210B 32-bit microcontroller. On dev-board's housing two copper plates were added for skin contact and measurement signal input. Inside the dev-board there is a custom built PCB with signal amplifiers and step-up (boost) converter. Source code is available for download on project page.
This device can be used as standalone portable ECG or even as a lie detector, and there is also a PC application for real-time data plotting via USB.
Source: Jingxi Zhang
OCT28
Capacitance meter with ATmega8
It is often required to know the precise capacitance of some capacitor which is in most cases different than the rated value.
This capacitance meter measures capacitance with 1pF resolution and in 1pF to 10000uF (10mF) range. Before initial measurement a calibration should be performed which is than saved in EEPROM of microcontroller. The device is realised on ATmega8 AVR and firmware is written in C which is available for download on the project page.
Source: Lars
OCT23
Small ATmega8 multi-use USB enabled board
It is always good when we have some kind of universal microcontroller board at hand.
This one is USB enabled with many IO pins exposed, LM1117 voltage regulator and ATmega8 AVR on board. There is a free firmware USB driver available that we can use to write our own code around. As the author states, this is version 1 and there is also version 2 which is much better and with even mode I/O pins exposed. There are also many projects built using this board such as temperature, humidity and pressure sensors and infra-red receiver for Kenwood keyboard on the project page.
Source: Raphael Assenat
OCT22
Gear clock based on PIC16F628A
We have seen all kinds of clocks, binary, nixie, led, vcr tape clocks, but this time we will see a big clock based on gears.
Current time is displayed as hours and minutes on two big gears which are made out of wood. They are turned by stepper motor which is controlled by PIC16F628A microcontroller that keeps track of time. This clock is adjusted by turning big gears by hand or by two push-buttons on the electronics board. Source code for PIC is available for download on project page, for all those electronic woodworkers.
Source: Alan Parekh
OCT21
Frequency generator with MAX038
Frequency generator or function generator is a signal generator of various shapes commonly used for electronic or acoustic equipment testing and debugging.
This frequency generator is based on MAX038 circuit from Maxim-IC and is controlled with PIC16F877 microcontroller. MAX038 circuit is able to generate signals with frequency of up to 20MHz which is pretty enough for most applications. Current signal being generated with this unit is displayed on character LCD. Project schematics is unfortunately not available but PCB, PCB with placed components diagram and HEX file is available for download on project page.
Source: DIY hifi
OCT19
Advanced RLC meter based on dsPIC
The RLC meter is not a very common device among hobbyists. Since we all are going towards building SMD projects we sure can use one of these devices because of vast number of unmarked SMD components around us.
Here you can see an RLC meter that can be built at home. It uses advanced DDS (direct digital synthesis) techniques for test signal generation and DSP (digital signal processing) techniques for analysis of resulting voltages and currents. It is based on dsPIC30F4012 16-bit Microchip DSP controller and measurement results are displayed on graphic LCD. Source code is written in C and is available for download on the project page.
Source: Miguel Rusch
OCT14
The absolute green soldering
Some time ago we have seen a Soldering press for cables and now we are looking at the solar power soldering method.
Even though this is not recommended for common use but in extreme situations (and I can't think of any at the moment) this can actually work pretty good. Soldering requires a lot of energy because solder melts at over 200 degrees Celsius and the metals in the electronic parts quickly conducts away heat. This can easily be achieved by focusing sunlight using biconvex lens on a very sunny day.
Source: Robot Room
