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28 Feb 2012

pyMCU is a python controlled MCU unlike other efforts out there that try to get the MCU to actually run python my approach is to use python on the computer to control the MCU. I’ve written a really optimized serial protocol and a python wrapper that lets you do the same kind of commands you would use if you were programming the MCU directly except its all done real-time on the computer so your essentially able to use the python interface on the computer to interact with the physical world. The current version has been tested and works on Windows, Linux, and OSX.

With more and more software having hooks into python the possibilities you can have with this are almost endless.

I think it can be a great product that falls somewhere between a basic stamp and an arduino and will be a great stepping stone for beginners to learn electronics and/or programming.

pyMCU – a python controlled MCU  - [Link]

28 Feb 2012

Sergei Bezrukov writes:

This project is based on Sensirion SHT15 humidity and temperature sensor. The sensor communicates with microcontroller by means of an I2C-like interface. Although this is a proprietary interface and not compatible with the standard I2C, it is very clearly described in the data-sheet.

I use the default 14-bit resolution for measuring the temperature and 12-bit resolution for humidity. The prototype also shows the atmosphere pressure sensor on the board and is an extension of the barometer project. This concerns usage of the pressure sensor, its interface with PIC, and communication with the LCD. The schematics below just shows the added parts to the barometer project.

Digital humidity meter - [Link]

26 Feb 2012

Sergei Bezrukov writes:

The radiometer is based on СБМ-20 Geiger counter tube which is manufactured in Russia and could be found on E-Bay. The counter is in a thin metal hull, so only beta and gamma rays can snick through it. It’s working voltage is in the range 350 – 450 V, the dead time does not exceed 190 μs, and the sensitivity is about 78 pulses per micro-roentgen. Therefore, maximum frequency of pulses provided by the counter is 106 / 190 = 5263 Hz. Respectively, the maximum radiation level one can register with it is 5263 / 78 = 67.47 μR/s, which is about 243 mR/h. The embedded firmware, however, can work up to 1 R/h.

Radiation dosimeter - Geiger counter - [Link]

26 Feb 2012

Company Hammond Manufacturing is probably familiar to you in context with high quality aluminium and plastic enclosures. But Hammond Manufacturing also produces a wide range of audio transformers, chokes and lamp transformers.

Audio transformers are mainly known to those, who work with professional sound equipment, microphones and high-end lamp amplifiers. A main function of transformers in audio devices is above all impedance matching. Various audio signal sources, like for example microphones, have an impedance different from impedance required for further signal transmission. Naturally, without impedance conversion, a direct connection into a transmission chain would cause a significant change of signal level, moreover frequency dependent, lower resistance to interference, or an overload of an end stage (at a lamp amplifier). At the same time transformers provide a galvanic disjunction, thus their usage is often convenient also from safety reasons.

Advantages / Features:

  1. top quality
  2. balanced frequency response
  3. low insertion loss

Hammond Manufacturing has long-term experience with a development and production of audio transformers. In a production portfolio we can find various series, from simple ones up to top wideband series, like for example the 850A series with a frequency response +/- 0.5 dB from 20 Hz to 20 KHz. Another group of components consist of lamp transformers. Here we can find output transformers, supply transformers, chokes, but even drivers and also many construction components.

Top quality Hammond audio transformers - [Link]

26 Feb 2012

Here is an app note from Texas Instruments explaining how to implement the Direct Cosine Matrix algorithm on a MSP430F5xx to integrate date form 3 sensors. A magnetometer, gyroscope, and a an accelerometer were integrated to provide a 9-axis sensor. [via]

When creating an AHRS, also known as Magnetic, Angular Rate, and Gravity sensor (MARG), a magnetometer, a gyroscope, and an accelerometer are required. The calibrated sensors readings are fed to the DCM algorithm, which provides a complete measurement of the orientation, relative to the  earth’s magnetic field and the direction of gravity, expressed by the Euler (roll, yaw, and pitch) angles.

App note: Implementing a 9-axis sensor fussion on the MSP430F5xx - [Link]

25 Feb 2012

Viktor made a sound trigger for his DSLR camera:

Now that I can take pictures of lightning I decided that I also want to be able to trigger my camera with sound.

An op-amp filters and amplifies a microphone signal. The output is fed to a PIC microcontroller that triggers the flash when the sound reaches a certain level. The trigger sound level and shutter delay are set with a pot.  [via]

Lil Bang – Sound trigger for cameras - [Link]

25 Feb 2012

An open source 512K SRAM memory module for adding extra ram to your project: [via]

I have designed a very simple PCB module that allows access to 512KBytes of Static RAM.  It is compatible with any microcontroller with at least 13 free digital IO pins and the ability to run from a 3.3v or 5v supply.

It uses four 128K x 8bit SRAM chips connected in parallel. This is a 4 layer board with components placed on both sides.

512K SRAM memory module with 13 pin interface - [Link]

25 Feb 2012

This is an app note from Maxim describing how to protect your Lithium Ion batteries from reverse insertion into the charger. The circuit is a Li-Ion battery charger with an added analog comparator designed to detect when then battery is inserted the wrong way and disconnect it from the charger. [via]

Combining a linear-mode single-cell lithium-ion battery charger (MAX1551) with a comparator (MAX9001) and n-channel FET adds a layer of reverse-battery protection that protects a single cell lithium-ion battery charger and battery from damage due to backwards insertion

Protect your batteries from reverse insertion - [Link]

25 Feb 2012

Here is a reference design from Microchip describing how to built a Light dimmer with a PIC12C508 and a few discrete components. The circuit uses a simple zener voltage doper, to drop the voltage from mains to 5V required by the PIC. Watch out, there is live mains voltage involved. [via]

This reference note describes an application where the use of a microcontroller was not reviously economically feasible for any but the highest end products: lamp dimming.

Lamp dimmer using PIC12C508 - [Link]

25 Feb 2012

Sergei Bezrukov writes:

The device is intended for measuring luminance in the range 0.025 – 99999 lux. The lower limit is determined by the used sensor MAX44007, while the upper one is slightly less than the sensor’s one because no more than 5 digits fit on the LCD screen. Calibration of the sensor is provided by the manufacturer.

Digital Lux Meter - [Link]





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