We do have some other handy level shifters in the shop, from the DIP 74LVC245 to the fancy bi-directional TXB0108. However, neither of these are happy to work with I2C, which uses a funky pull-up system to transfer data back and forth. This level shifter board combines the ease-of-use of the bi-directional TXB0108 with an I2C-compatible FET design following NXP’s app note.
This breakout has 4 BSS138 FETs with 10K pullups. It works down to 1.8V on the low side, and up to 10V on the high side. The 10K’s do make the interface a little more sluggish than using a TXB0108 or 74LVC245 so we suggest checking those out if you need high-speed transfer.
While we designed it for use with I2C, this works great for SPI, TTL Serial, and any other digital interface both uni-directional and bidirectional. Comes with a fully assembled, and tested PCB with 4 full bidirectional converter lines as well as 2 pieces of 6-pin header you can solder on to plug into a breadboard or perfboard.
UPDATED – NEW PRODUCT! ADXL335 – 5V ready triple-axis accelerometer (+-3g analog out). We’ve updated our favorite triple-axis accelerometer to now have an on-board 3.3V regulator – making it a perfect choice for interfacing with a 5V microcontroller such as the Arduino. This breakout comes with 3 analog outputs for X, Y and Z axis measurements on a 0.75″x0.75″ breakout board. The ADXL335 is the latest and greatest from Analog Devices, known for their exceptional quality MEMS devices. The VCC takes up to 5V in and regulates it to 3.3V with an output pin. The analog outputs are ratiometric: that means that 0g measurement output is always at half of the 3.3V output (1.65V), -3g is at 0v and 3g is at 3.3V with full scaling in between.
Fully assembled and tested. Comes with 8 pin 0.1″ standard header in case you want to use it with a breadboard or perfboard. Two 2mm (0.08″) mounting holes for easy attachment.
NEW PRODUCT – Analog 2-axis Thumb Joystick with Select Button + Breakout Board. This mini-kit makes it easy to mount a PSP/Xbox-like thumb joystick to your project. The thumbstick is an analog joystick – more accurate and sensitive than just ‘directional’ joysticks – with a ‘press in to select’ button. Since it’s analog, you’ll need to analog reading pins on your microcontroller to determine X and Y. Having an extra digital input will let you read the switch.
The pack comes in three parts – the joystick itself, a soft-touch rubber ‘hat’ and a nicely designed breakout board. We designed the breakout so that you can attach the joystick to a panel easily – every other breakout we wanted to carry had the mounting holes so they were in the way of the joystick movement! A 5 pin 0.1″ spaced header makes it easy to connect either in a perfboard/breadboard setting or free wiring. You’ll need to solder the joystick into the PCB using a soldering iron and solder, but its very simple and will only take a minute.
UPDATED AND BACK IN STOCK – Atmega32u4 Breakout Board. Toss out those FTDI cables and go USB-native with the ATmega32u4. After many months of back-orders, we finally received a shipment of these little guys and are excited to offer our breakout board. The little dev board keeps it simple, with just the bare essentials:
Atmega32u4 – AVR core with USB capability. 32K flash, 2.5K RAM running at 16MHz
Standard AVR 6-pin ISP connector for direct programming (when you need the extra space)
Big Bootload/Reset button
500mA fuse on the USB power line
Power LED and ‘user’ LED (also indicates when the bootloader is active)
Fits nicely in any breadboard
4 mounting holes
This breakout board is best for those who have familiarity with some microcontrollers and are comfortable with writing code in C. This board doesn’t come with any ‘learn to program’ tutorials! If this is your first time with a microcontroller, we suggest going with an Arduino which is easier. Then when you want to upgrade, check this out.
Plug it in, connect a mini-B USB cable and you can start writing code immediately. With the built-in bootloader you don’t even need an AVR programmer. We suggest checking out the LUFA library to get started with the USB core as nearly every kind of device has an example already.
The TSL2561 luminosity sensor is an advanced digital light sensor, ideal for use in a wide range of light situations. Compared to low cost CdS cells, this sensor is more precise, allowing for exact Lux calculations and can be configured for different gain/timing ranges to detect light ranges from up to 0.1 – 40,000+ Lux on the fly. The best part of this sensor is that it contains both infrared and full spectrum diodes! That means you can seperately measure infrared, full-spectrum or human-visible light. Most sensors can only detect one or the other, which does not accurately represent what human eyes see (since we cannot perceive the IR light that is detected by most photo diodes).
NEW PRODUCT – TSL2561 digital luminosity / lux / light sensor. The TSL2561 luminosity sensor is an advanced digital light sensor, ideal for use in a wide range of light situations. Compared to low cost CdS cells, this sensor is more precise, allowing for exact lux calculations and can be configured for different gain/timing ranges to detect light ranges from up to 0.1 – 40,000+ Lux on the fly. The best part of this sensor is that it contains both infrared and full spectrum diodes! That means you can separately measure infrared, full-spectrum or human-visible light. Most sensors can only detect one or the other, which does not accurately represent what human eyes see (since we cannot perceive the IR light that is detected by most photo diodes)
The sensor has a digital (i2c) interface. You can select one of three addresses so you can have up to three sensors on one board – each with a different i2c address. The built in ADC means you can use this with any microcontroller, even if it doesn’t have analog inputs. The current draw is extremely low, so its great for low power data-logging systems. about 0.5mA when actively sensing, and less than 15 uA when in powerdown mode.
Of course, we wouldn’t leave you with a datasheet and a “good luck!” – we wrote a detailed tutorial showing how to wire up the sensor, use it with an Arduino and example code that gets readings and calculates lux.
The shape is a bit different, but both boards work as intended. Both have LEDs, but the Gravitech LED is on whenever a card is inserted (I think using the socket’s mechanical card detect switch) and the Adafruit LED blinks while data is transferred to/from the card, which I think is the more useful function. Both have “push/push” type sockets (to release card, push in, it clicks and springs back out). They are from different vendors; the Gravitech sockets seemed to have a bit more friction and were more sticky overall, and tend to grab on to the cards rather than release them cleanly, but they seem to improve a bit after a few cycles.
Looks like we did good, our LEDs blink on data transfer and our sockets release cleanly out of the box The SD sockets are always hit or miss depending on the maker.
Micro SD card Tutorial How to add lots o’ storage with microSD (and SD) cards. If you have a project with any audio, video, graphics, data logging, etc in it, you’ll find that having a removable storage option is essential. Most microcontrollers have extremely limited built-in storage. For example, even the Arduino Mega chip (the Atmega2560) has a mere 4Kbytes of EEPROM storage. There’s more flash (256K) but you cant write to it as easily and you have to be careful if you want to store information in flash that you don’t overwrite the program itself!
Klout exposes a web service enabling developers to build mash-up applications around its metrics and all that is required to play is an API key which is easily obtained when registering an application. My application is the “Klout Klock” device and before getting into the details of building it, you can see it how it works in this video…
The clock is built using a Netduino Plus and an AdaFruit ST7735 TFT screen. I have described how to connect them together in a previous post here. In that post, I had indicated that managing such a TFT screen from a Netduino was sub-optimal due to the memory requirements involved. That statement is even more true with a Netduino Plus which has roughly 28KB of RAM available for an application. This means that allocating a 40KB buffer to manage the TFT display as I was doing it previously is out of the question.
This tutorial is for our new BMP085 Barometric Pressure sensor. We show how to wire it up to your microcontroller, read the current pressure and temperature from the chip. We also show how to calculate altitude and weather-corrected altitude.
The BMP085 is a basic sensor that is designed specifically for measuring barometric pressure (it also does temperature measurement on the side to help). It’s one of the few sensors that does this measurement, and its fairly low cost so you’ll see it used a lot. You may be wondering why someone would want to measure atmospheric pressure, but its actually really useful for two things. One is to measure altitude. As we travel from below sea level to a high mountain, the air pressure decreases. That means that if we measure the pressure we can determine our altitude – handy when we don’t want the expense or size of a GPS unit. Secondly, atmospheric pressure can be used as a predictor of weather which is why weathercasters often talk about “pressure systems”