Tag Archives: Mcu

Build a Simple Toaster Oven Temperature Profile Controller


Maurizio @ dev.emcelettronica.com has tipped us about his latest project. In this article he discuss how to build a simple toaster oven temperature profile controller using StickOS and CPUStick. This is the first part of the article.

Using a highly-integrated microcontroller running “StickOS BASIC”, it is possible to quickly build a toaster oven temperature profile controller for performing surface mount (SMT) printed circuit board reflow soldering at home. It is also possible to program a large variety of other general-purpose embedded system projects with minimal software effort, using only a terminal emulator and high-level BASIC algorithmic statements to manipulate the microcontroller (MCU) pins and peripherals.

Build a Simple Toaster Oven Temperature Profile Controller – [Part 1] [Part 2]

A development board for the STM32F042


Andy Brown designed a development board for the STM32F042 in the TSSOP20 package:

This project came about because I’m using the STM32F042F6P6 (32Kb flash, 6Kb SRAM) in another project where I’m creating a USB device and the first thing I did is try to obtain a development board for it. I was hopeful that ST would have created one of their ‘discovery’ boards but no, there was only a ‘nucleo’ board available and that had one of the QFP packages on it.

A development board for the STM32F042 – [Link]

Pixie – 3W chainable smart LED Pixel


Ytai Ben-Tsvi @ ytai-mer.blogspot.com build a PIC based 3W LED Driver that is chainable. He writes:

LED Pixel: The Pixie is a color LED module, allowing an external controller to change its color and brightness dynamically.
Chainable: The module is designed so that you can chain many of them and control each one individually. If you know NeoPixels, this concept should be clear, but in case you don’t, imagine you want to build a project that requires 50 LEDs to be individually controlled. Naively, you would need to power each on of them individually, then connect each one of them individually to a controller. This would require tons of wiring, many pins on the controller, each one possibly driven by a specialized peripheral, such as UART or PWM. In short, this is not practical. With the Pixie, being chainable, you connect the first LED’s input pins to power and a single control pin (serial TX) on the controller. Then you connect the first LED’s output pins (power, ground, data) to the input of the second LED, and so on. Each Pixie in the chain consumes its own data, then relays the rest of the data down the chain, so the controller can control each Pixie individually, without being connected to each one.

Pixie – 3W chainable smart LED Pixel – [Link]

Non-Contact Body Temperature Meter

One of the most commonly used medical instruments nowadays is the thermometer. The thermometer is used to monitor or measure the body temperature of a sick person. The idea of creating a thermometer started from a device called thermoscope, a thermometer without a scale. Several inventors developed it until Sir Thomas Allbutt invented the first practical 6-inch medical thermometer able to sense a body temperature in five minutes. The development of the thermometer did not stop there and today, digital thermometer exists which is faster and very accurate.

This reference design is an example of a low cost non-contact digital thermometer. It only uses a microcontroller, a four digit seven segment display and an infrared (IR) temperature sensor. The concept of this design is to make the IR sensor measure the temperature of the thermal radiation emitted by the body being measured. The data acquired by the sensor will be sent to the microcontroller through the I2C bus. The microcontroller will analyze the data and then shows the body temperature on the four-digit seven-segment display.

The circuit of this reference design uses few components only and is very easy to understand. However, to make the circuit function accurately, software calibration must be implemented carefully. The whole circuit is powered by a 5V DC power supply regulated from the four 20mm coin shape batteries contained in a 120591-1 TE Connectivity battery holder. The batteries are connected in series-parallel connection to produce a 6V 480mAh source of power. With the help of a low-dropout voltage regulator, the 6V is regulated to a 5V DC supply

Non-Contact Body Temperature Meter – [Link]

RC Servo Driver 0-5V


0 – 5V Servo Controller project will control a hobby type servo motor connected to it via a preset or external DC source.  This kit will be ideal add on in animatronics and motion control application.

This is a simple but a useful circuit to control a single servo motor.  Its an ideal add on to a RC Hobbyist tool kit. The DC input to this circuit should be 5 to 6 VDC.  DC signal is given to this board at connector marked CN1 (+V and GND).   You can also feed in a variable DC signal source at the other two pins on this connector to control the servo.  To use this signal source you need to place the Jumper link at J1 in the E position.  Alternatively, you can also control the servo motor by preset PR1 mounted on the PCB.  For this you need to place the Jumper link in the I position at J1.A Servo motor is connected at connector marked CN2 on the PCB.  This connector has all the pins clearly marked for connection to the servo.LED D1 is a power on indicator ,  Diode D2 provides a reverse polarity protection for the Microcontroller.


  • Microcontroller based design for greater flexibility and ease of control
  • Single Servo control via clearly marked berg connector
  • Clearly marked jumper to select signal source to control the Servo
  • Onboard preset for ready to control option for this kit
  • Power-on LED indicator
  • Diode protection for reverse polarity connection of DC supply to the PCB
  • Four mounting holes 3.2 mm each
  • PCB dimensions 45 mm x 32 mm

RC Servo Driver 0-5V – [Link]

Wrist Mount Digital Altimeter

This project is a simple wrist mount digital altimeter which is a device used to determine altitude. This design uses atmospheric pressure to calculate the altitude of its location. The lower the atmospheric pressure, the higher the altitude. The project is comprised of a microcontroller (MCU), an 84×84 pixel graphic LCD and a barometric pressure sensor.

The barometric pressure sensor used in the design is the MS560702BA03-50 from TE Connectivity Measurement Specialties. It consists of a piezo-resistive sensor and a sensor interface IC. Its main function is to convert the uncompensated analogue output voltage from the piezo-resistive pressure sensor to a 24-bit digital value, as well as providing a 24-bit digital value for the temperature of the sensor. It is optimized for altimeters and variometers with an altitude resolution of 20cm. The MS560702BA03-50 measures the atmospheric pressure on its location then converts it to a 24-bit value through its internal ADC. The sensor reading is then transmitted to the MCU through SPI. Then the MCU calculates the altitude by using the pressure reading. The calibration of an altimeter follows the equation z = cT log (Po /P), where c is a constant, T is the absolute temperature, P is the pressure at altitude z, and Po is the pressure at sea level. The calculated altitude is then displayed through an 84×84 pixel graphic LCD which is mostly found on old phones. The circuit is powered through a 3.3V battery.

The altimeter is used to aid navigation and is mostly used in skydiving, mountaineering and hiking applications. It is usually hand-held or in wrist-mount form for the ease of use. Altimeters can also be found in aircrafts such as planes and helicopters and others that needs altitude indication.

Wrist Mount Digital Altimeter – [Link]

DIY milliohmmeter


by hwmakers.eu:

This is an example of a simple and cheap milliohmmeter that can be made by every maker. The core of the circuit are a current source (LT3092) and a current sense (INA225): a costant current flows through the milliohm resistor under test and the voltage at the current sense output gives the value of the resistor (V=R*I).

The milliohmmeter can be used as a stand alone instrument by adding a MCU with at least 10 bit ADC and a LCD display or it can be used togheter with a DMM.

DIY milliohmmeter – [Link]

Rad tolerant megaAVR MCU for space & avionics applications


by Graham Prophet @ edn-europe.com:

Atmel ATmegaS128 AVR microcontrollers are now produced in space-grade quality, including latch-up immunity, ceramic packaging and extended temperature range for next-generation of space applications.

AtmegaS128 – the first µC Rad Tolerant device for Atmel – delivers full wafer lot traceability, 64-lead ceramic package (CQFP), space screening, space qualification according to QML and ESCC flow and total ionising dose up to 30 krad (300 Gy Si) for space applications. The ATMegaS128 is “latch up” immune thanks to a dedicated silicon process: SEL LET > 62.5Mev at 125°C, 8 MHz/3.3V. SEU to heavy ions is estimated to 10-3 error/device/day for Low Earth Orbit applications.

Rad tolerant megaAVR MCU for space & avionics applications – [Link]

Password Based Circuit Breaker

Electrical accidents are rapidly increasing especially electric line repairs incident due to the lack of communication and coordination between the maintenance personnel and the electric substation staff. The password based circuit breaker device could just be the solution as only the lineman could reliably control the circuit breaker to avoid miscommunication. The system requires a password to turn ON/OFF the circuit breaker as needed. It is entirely controlled by 8051 family microcontroller specifically the SST89E54RDA-40-C-PIE, an 8-bit microcontroller that is a member of the Flash Flex family.

The circuit consists of 8051 series controller, 4×3 keypad, LCD, relays and two loads. LCD data pins are connected to port1 and control pins RS, RW, EN pins are connected to P3.7, P3.6 and P3.5 respectively. The keypad is connected to port 2 of the controller while the LCD is used to display the information. In addition, the lamp and motor are connected to P3.0 and P3.1 through the relays. These are used to indicate circuit breaker state. Moreover, BC547 transistors are used to drive the relays where 5V relays are used to drive the AC loads. While giving the connections, there should be no common connection between AC and DC supplies. Furthermore, a 5V power supply is used to provide regulated 5V DC to the controller.

This project distinctly provides security and convenience to electrical maintenance personnel. This may help avoid fatal accidents to line man, which can be used in establishments such as building offices, hotels, industries and houses. It is a simple project with commonly available components that helps save life.

Password Based Circuit Breaker – [Link]