3.3V to 30V DC/DC converter using SN6505A

sn6505a_circuit

Bob tipped us with his latest project. It’s a 3V3/30V DC/DC converter using SN6505A from TI.

Recently I’v got my samples of SN6505A, it’s a really nice IC, so I decided to make a simple DC/DC converter to get familiar with it. What I like in this chip is that it can operate on input voltage as low as 2,5V – that makes it great for battery devices. It’s also nice, that it’s a very minimalist design – on primary side all what is needed is decoupling capacitor. One disadvantage is that it doesn’t have a feedback loop.

3.3V to 30V DC/DC converter using SN6505A – [Link]

DIY 32ch FPV 5.8ghz LCD

DSC_0343-600

Spikey made his own DIY 32ch FPV 5.8ghz LCD. He writes:

If you’re like me, you don like buying stuff that’s ready-to-go, but rather build one yourself. We usually spend more money, but it’s way more satisfying I really didn’t want to buy an overly expensive FPV LCD receiver, so I made my own DIY 32ch FPV 5.8ghz LCD, that is compatible with EVERY transmitter on the market now.

DIY 32ch FPV 5.8ghz LCD – [Link]

Simple crystal tester

26656519722_cdebd7e170_z-600x398

Dilshan Jayakody build a simple crystal tester based on Colpitts oscillator. He writes:

This is simple Colpitts oscillator to test commonly available passive crystals which range between 2MHz to 27MHz. This unit must connect to an oscilloscope and/or frequency counter to get the frequency of the crystal. This circuit is design to work around 9V to 12V DC power source. Both 2SC930 transistors can replace with any high speed NPN transistor such as 2SC829, 2SC933, etc.

Simple crystal tester – [Link]

DS1307 RTC Module

RTC-DS1307-MODULE-SMD-C089C-500x500

The module based on DS1307, The DS1307 serial real-time clock (RTC) is a low-power, full binary-coded decimal (BCD) clock/calendar plus 56 bytes of NV SRAM. Address and data are transferred serially through an I²C, bidirectional bus. The clock/calendar provides seconds, minutes, hours, day, date, month, and year information. The end of the month date is automatically adjusted for months with fewer than 31 days, including corrections for leap year. The clock operates in either the 24-hour or 12-hour format with AM/PM indicator. The DS1307 has a built-in power-sense circuit that detects power failures and automatically switches to the backup supply. Timekeeping operation continues while the part operates from the backup supply.

Specifications

  • Supply 5V DC
  • Completely Manages All Timekeeping Functions
  • Real-Time Clock Counts Seconds, Minutes, Hours, Date of the Month, Month, Day of the Week, and Year with Leap-Year Compensation Valid Up to 2100
  • 56-Byte, Battery-Backed, General-Purpose RAM with Unlimited Writes
  • Programmable Square-Wave Output Signal
  • Simple Serial Port Interfaces to Most Microcontrollers

DS1307 RTC Module – [Link]

Using a Current Shunt with a Panel Meter / Ammeter scale change

This video gives you the basics of how to calculate and use a simple resistive current shunt with an analog panel meter to change the current that is needed for a full scale deflection. The notes page for this video can be found here.

Using a Current Shunt with a Panel Meter / Ammeter scale change – [Link]

ulibSD – a library for use SD cards in SPI mode with uControllers

SD_Card_SPI

electronictechnician.wordpress.com has published a library for use SD cards in SPI completely written in C.

It’s a library for use SD cards in SPI mode with uControllers, entirely written in C. This library can work with SD cards and also has the possibility to emulate the behavior in a PC file (GNU/Linux) using the macro _M_IX86. It’s for debugging purposes. The data transfer is oriented to 512 byte size, remember this.

ulibSD – a library for use SD cards in SPI mode with uControllers – [Link]

Hacking a UART on a blood pressure cuff

default

moamindustries.com hacked an Omron RS8 blood pressure cuff by adding a UART interface to it.

As part of a prototype developed 12 months ago I was tasked with reading measurements from a blood pressure cuff [sphygmomanometer] in real time. Not surprisingly there are no consumer level devices that have a serial interface because what ‘normal’ person would want such a thing!

Initially we considered our own interface for a blood pressure cuff. Just run the pump and take the readings with our own processor and pressure sensor, how hard can it be.

Hacking a UART on a blood pressure cuff – [Link]

WISP – Wireless Identification and Sensing Platform

WISP4

WISP, the Wireless Identification and Sensing Platform, is a family of sensors that are powered and read by UHF RFID readers.

WISP, the Wireless Identification and Sensing Platform, is a family of sensors that are powered and read by UHF RFID readers. WISPs do not require batteries since they harvest their power from the RF signal generated by the reader. The WISP is an open source, open architecture EPC Class 1 Generation 2 RFID tag that includes a fully programmable 16 bit microcontroller, as well as arbitrary sensors.

WISP – Wireless Identification and Sensing Platform – [Link]

Hacking home weather station transmitter

IMG_2378

Bob hacked a home weather station transmitter and made a home thermometer from it. He writes:

Recently I’ve found this piece of electronic on the dumpster, it was looking interesting – compact case with battery holder, LCD display, temperature and humidity sensor. It has also radio transmitter, but I’m not interested in it since I don’t have the receiver station. I decided to bring it back to life.

Hacking home weather station transmitter – [Link]