Shared Projects by PeskyProducts

ST Microelectronic’s ultra-low-power real time clock coupled with Measurement Specialties MS5637 pressure and temperature sensor and ST’s M2402DFC 2Mbit EEPROM in an appallingly small add-on board for Teensy 3.1. Power is supplied via digital write to general GPIO pins since the total power requirement never exceeds 2 mA. Communication is via I2C and there are 4K7 pullup resistors on board. The temperature sensor allows the Teensy 3.1 microcontroller to make periodic calibration updates to the RTC calibration register so the clock remains temperature compensated for maximum (~2 ppm or 1 minute a year) accuracy. The clock outputs the usual date, days, hours, minutes, etc. but also outputs tenths of seconds as well as hundredths of a second.The on-board EEPROM is useful for data logging and storing alarm patterns (music) for output to a small speaker. With 2 Mbits (256 kBytes), lots of data can be logged and dozens of alarm sounds can be stored; one for every occasion! Added Taiyo Yuden PAS3225 2.6V 14 mF super capacitor and 1N4148 diode to provide power to the RTC time keeper even when disconnected from the microcontroller. The PAS3225 5 microAhour super cap can run the RTC (which needs ~330 nA at 2.6 V) for about 15 hours. Added ST Microelectronics' HTS221 16-bit, ultra-low-power relative humidity sensor. The board is now a tiny weather logging station: pressure, temperature, and humidity can be logged once per minute for 15 days!

BMX-055 9-axis motion sensor and MS5637 pressure sensor add-on for teensy 3.1 with hardwired I2C. Added solder jumpers on back of board so 3V3 and GND can be taken from the board edge for better breadboard use.

MPU9250 9-axis motion sensor and MS5637 pressure sensor add-on for Teensy 3.1 hardwired for I2C. Added solder jumpers to take power and ground from board edge for easier breadboarding. Readjusted position of bypass capacitor.

Nordic Semiconductor’s low-power 2.4 GHz RF radio with pcb antenna and matching circuit per Nordic’s spec. Using much smaller XRCHA16M Murata crystal to reduce cost and board size. Improved layout and ground pattern slightly, corrected silkscreen error.

Breakout board with two independently addressable ST Microelectronics' 2 Mbit (256 kbyte) M24M02-DRC I2C EEPROMs designed to be mounted onto the Teensy 3.1 and use digitalWrite for power and ground due to the very low-power (< 2 mA per EEPROM) requirements. Can also be used as a traditional breakout board since VIN ranges from 1.8 to 5.5 V. Cutting one or both traces between the solder jumpers enables write protect mode allowing access to the data already written but disallowing further write operations. The write protect is reversible by simply soldering the junction again. Operating temperature range is -40 C to +85 C making this an ideal solution for portable/remote data logging when power and space are at a premium. EEPROM write operational for 4 million write cycles and data is retained for 200 years! Minimized width to make it even more appallingly small!