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What are the most used MIFARE chips?...card readers

 by esm. ¦  Tue Mar 13, 2012 8:00 am ¦  Forum: SparkFun Product Questions ¦  Topic: What are the most used MIFARE chips?...card readers ¦  Replies: 0 ¦  Views: 381

Hi. Somebody know what are the most commom Mifare ICs produced by Philips? Or other manufacturers... I want to read the ID of cards (to make a person identifier system), I won't write anything to them, just read the ID. Somebody already had experience with these MIFARE ICs? The price of the componen...

Buck DC-DC converter ICs, with internal MOSFET and freewheel

 by esm. ¦  Sun Mar 11, 2012 8:00 pm ¦  Forum: SparkFun Product Questions ¦  Topic: Buck DC-DC converter ICs, with internal MOSFET and freewheel ¦  Replies: 1 ¦  Views: 347

Hi. I am looking for a buck converter IC available in a small SMD package like SOT-23 (or other small one) to a power supply with these parameters: Vin = 16 to 30VDC Vout = 4.4VDC Iout = 250mA The maximum output peak current is also 250mA. The 4,4V rail will be used to supply voltage to a constant c...

Li-Ion (Lithium) Battery - Charger and protection ICs ???

 by esm. ¦  Sat Mar 03, 2012 12:51 pm ¦  Forum: SparkFun Product Questions ¦  Topic: Li-Ion (Lithium) Battery - Charger and protection ICs ??? ¦  Replies: 0 ¦  Views: 328

Hi. I am designing a power supply where I will also need to use a backup battery. The choosen battery type was a Li-Ion (Lithium) type, which has a nominal cell voltage of 3.7V . I have little experience with battery chargers and protection circuits (using dedicated ICs). --> I searching for dedicat...

Boost Controllers for 3.3V to 12~24V conversion

 by esm. ¦  Sat Mar 03, 2012 10:43 am ¦  Forum: SparkFun Product Questions ¦  Topic: Boost Controllers for 3.3V to 12~24V conversion ¦  Replies: 0 ¦  Views: 237

Hello sirs. I have a PCB where I have a precision 3.3V power supply with 1A capacity. I will need another power supply with 12V or 15V or 20V or 24V capable of supplying around 80mA DC, generated from this 3V3 rail. I will change the PCB layout when needed, and the only power source available to gen...

Analog differential input - how to make it measure 0V when f

 by esm. ¦  Fri Feb 24, 2012 9:03 am ¦  Forum: SparkFun Product Questions ¦  Topic: Analog differential input - how to make it measure 0V when f ¦  Replies: 1 ¦  Views: 303

Hello. I am using an external ADC (MCP3421), 16-bit resolution, with internal PGA (internal gain) of 8x to read signals from a thermocouple type T. Within my current ADC configuration, the differential input impedance is around 280K. But when the inputs are floating, the result of ADC conversions be...

Recording video, converting and storing to a microSD - Dedic

 by esm. ¦  Sun Feb 19, 2012 3:18 pm ¦  Forum: SparkFun Product Questions ¦  Topic: Recording video, converting and storing to a microSD - Dedic ¦  Replies: 0 ¦  Views: 247

Hello all. I starting a new project where I need to record video (and optionally audio) with a small camera (no need of high quality video record), convert the video do a known format, like MPEG, AVI or other who require less disk space (mp4, flv etc). I need to store them to a microSD card, hard di...