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DescriptionThe SN74HC595N is a simple 8-bit shift register IC. Simply put， this shift register is a device that allows additional inputs or outputs to be added to a microcontroller by converting data between parallel and serial formats. Your chosen microprocessor is able to communicate with the The SN74HC595N using serial information then gathers or outputs information in a parallel(multi-pin)format. Essentially it takes 8 bits from the serial input and then outputs them to 8 pins.This small DIP packaged IC contains an 8-bit， serial-in parallel-out shift register that feeds an 8-bit D-type storage register with parallel 3-state outputs.Note：This is a drop-in replacement for the 74HC595 shift register IC and should function just fine in any application the previous version could.Get started with the Shift Register GuideFeatures8-Bit Serial-In， Parallel-Out ShiftWide Operating Voltage Range of 2 V to 6 VHigh-Current 3-State Outputs Can Drive Up to 15 LSTTL LoadsLow Power Consumption：80-μA±6-mA Output Drive at 5 V

DescriptionThis is a 16mm deluxe thumb joystick and is very similar to the 'analog' joysticks found inside PlayStation controllers. Directional movements are provided simply by two potentiometers - one for each axis. These 10k potentiometers will read the position changes for the joystick's full range of physical motion. This joystick also has a select button that is actuated when the joystick is pressed down.The mechanical parts found in this joystick are mostly metal and are considered far sturdier(rugged， if you will)than other， plastic joystick options.Note：This thumb joystick does not include a top cap and it will need to be purchased separately. Additionally， the leads on the housing of this joystick are much thicker than the leads on the trimpots &； push button components. When soldering to BOB-9110， we recommend using a pair of fine tip tweezers to guide each pin into the correct hole before pushing down.

DescriptionThe Lock Stop is a low profile， high-quality stainless steel stop that can be used on the Nomad or the Shapeoko in conjunction with the Tiger Claw(Standard or Compact)， or Gator Tooth Clamps.These hard stops help secure your job with a tight grip and serrated face， no matter what you're making.

DescriptionPassive Infrared(PIR)sensors are great for detecting motion in a small area around the sensor. The 170μA SparkFun EKMC4607112K PIR Breakout is a simple board equipped with an EKM-series PIR sensor from Panasonic(R). The EKM-series PIR sensors are optimized for small movements to offer motion-sensing options for continuously powered applications.PIR sensors do not return specific distance data but instead monitor for IR light coming from objects in their field of view and will activate their signal when motion is detected in their sensing area， making them perfect for applications such as turning devices on automatically when motion is detected. Applications include home and building automation for energy saving， automated on/off lighting control， security， appliances， and IoT.Panasonic's low-profile PIR motion sensors(10.9mm versus standard 14.4mm height offer space savings for constrained designs)consist of a lens to create various detection zones， an optical filter to block non-infrared light， pyroelectric sensing elements， electromagnetic shielding to all circuitry， and an impedance converter to get an electrical signal. This PIR sensor offers digital output across 32 zones at 5m detection distance with 90°×90° detection area.Note：The sensitivity of passive infrared sensors is influenced by environmental conditions， so a performance evaluation test under representative conditions is recommended.Get Started with the SparkFun PIR Breakout GuideFeaturesOperating Voltage：2.3-4.0V170 μAstandby current consumptionLens diameter - 10.4mmLens Height - 10.9mm5m detection distance90°×90°(±45°)detection area

DescriptionThe SparkFun LSM6DSO 6 Degrees of Freedom Breakout is an accelerometer and gyroscope sensor with a giant 9kB FIFO buffer and embedded processing interrupt functions. Due to the capabilities and low cost of the LSM6DSO we've created this small breakout board just for you! Each LSM6DSO breakout has been designed to be super-flexible and can be configured specifically for many applications. With the LSM6DSO breakout you will be able to detect shocks， tilt， motion， taps， count steps， and even read the temperature!The LSM6DSO from STMicroelectronics is capable of reading accelerometer and gyroscope data up to 6.66kHz for more accurate movement sensing. As stated before this breakout also has the ability to buffer up to 9kB of data between reads， host other sensors， and drive interrupt pins all thanks to the LSM6DSO's built-in FIFO.Utilizing our handy Qwiic system， no soldering is required to connect it to the rest of your system. However， we still have broken out 0.1"-spaced pins in case you prefer to use a breadboard. Each pin has been broken out on the LSM6DSO， with one side of the board featuring power， I2C， and SPI functionality while the other side sporting pins that control auxiliary functionality and interrupt outputs. Please keep in mind that the LSM6DSO is a 3.3V device so supplying voltages greater than ～3.6V can permanently damage the IC. A logic level shifter is required for any development platform operating at 5V.The SparkFun Qwiic Connect System is an ecosystem of I2C sensors， actuators， shields and cables that make prototyping faster and less prone to error. All Qwiic-enabled boards use a common 1mm pitch， 4-pin JST connector. This reduces the amount of required PCB space， and polarized connections mean you can't hook it up wrong.Get Started With the SparkFun LSM6DSO Qwiic 6DoF GuideFeatures2x Qwiic connectorsI2C Address0x6B(default)， 0x6AAccelerometer measurement range±2/±4/±8/±16 g full scaleGyro measurement range±125/±250/±500/±1000/±2000 dps full scaleEmbedded temperature sensor16-bit resolutionOperating voltage range1.71V to 3.6VTypically3.3Vif using the Qwiic cablePower consumption @ 1.8V0.55 mA in combo high-performance mode0.265 mA in combo low-power mode"Always on" experience with low power consumption for both accelerometer and gyroscopeI2C/SPI serial interface with main processor data synchronization featureSmart FIFO up to 9 kbyte based on features setOperating temperature range-40℃ to +85℃

DescriptionThe Lock Stop is a low profile， high-quality stainless steel stop that can be used on the Nomad or the Shapeoko in conjunction with the Tiger Claw(Standard or Compact)， or Gator Tooth Clamps.These hard stops help secure your job with a tight grip and serrated face， no matter what you're making.

DescriptionThe TFMini Plus is a ToF(Time of Flight)LiDAR sensor capable of measuring the distance to an object as close as 10 centimeters(+/- 5cm up to 6m)and as far as 12 meters(+/-1% starting at 6m)! As with all LiDAR sensors， your effective detection distance will vary depending on lighting conditions and the reflectivity of your target object， but what makes this sensor special is its size. Measuring only 35x18.5x21mm， the TFMini Plus allows you to integrate LiDAR into applications traditionally reserved for smaller sensors.Setting itself apart from the original TFmini， the TFmini Plus has been designed with an IP65 enclosure meaning its "Dust tight water resistant"， and also passed the vibration test of drone level， which will greatly expand its application range. The TFMini Plus is easy to power at only 5V and easy to talk to using the UART communication protocol.Important：This product does not use laser light for ranging. Instead it contains an LED and optics. Many such systems are being marketed under the name "LiDAR，" although it may be more appropriate to think of this device as a "Time-of-Flight Infrared Rangefinder". It differs significantly from traditional IR rangefinders in that it uses ToF to determine range and not triangulation ― as is performed by the Sharp GP-series devices.FeaturesOperating Range - 0.1m～12m1Accuracy - ±5cm@(0.1-6m)， ±1%@(6m-12m)Distance resolution - 5mmFrame rate - 1-1000Hz(adjustable)Ambient light immunity - 70kluxOperating temperature - -20℃～60℃Enclosure rating - IP65Light source - LEDCentral wavelength - 850nmFOV - 3.6°Supply voltage - 5V±0.5VAverage current - ≦110mAPower consumption - 550mWPeak current - 500mACommunication level - LVTTL(3.3V)Material of enclosure - ABS+PCStorage temperature - -20℃～75℃Weight - 11gWire length - 30cm

DescriptionThis 8mp camera module is capable of 1080p video and still images that connect directly to your Raspberry Pi. This is the plug-and-play-compatible latest version of the Raspbian operating system， making it perfect for time-lapse photography， recording video， motion detection and security applications. Connect the included ribbon cable to the CSI(Camera Serial Interface)port on your Raspberry Pi， and you are good to go!The board itself is tiny， at around 25mm×23mm×9mm and weighing in at just over 3g， making it perfect for mobile or other applications where size and weight are important. The sensor has a native resolution of 8 megapixel， and has a fixed focus lens on board. In terms of still images， the camera is capable of 3280×2464 pixel static images， and also supports 1080p30， 720p60 and 640x480p90 video.Note：This module is only capable of taking pictures and video， not sound.FeaturesImage Sensor：Sony IMX219Maximum Photo Resolution：3280×2464 pixelSupported Video Resolution：1080p30， 720p60 and 640x480p90Physical Dimensions：25mm×23mm×9mmInterface：CSI connector(15cm ribbon cable included)Supported OS：Raspbian(latest version recommended)

DescriptionThis 2x20 "tall" header has the same number and spacing of pins as a Raspberry Pi and provides your board with the ability to extend the heights of your GPIO to accommodate for enclosures or other parts that can encapsulate your Pi. This th

DescriptionA Wide Band， 700-2700Mhz frequency range， 4G LTE antenna provides a wide enough range for a number of applications including BLE LoRa/RF. This antenna is 53mm×24mm with a 100mm length coaxial cable ending in an IPEX(u.FL equivalent)conn

DescriptionNeed to keep track of the airflow in your data center or around your servers? How about making sure your HVAC and air control systems are functioning at full capacity? Well， the new SparkFun FS3000-1005 Air Velocity Sensor Breakout can help you with all that and more! It's super easy and super quick(Qwiic!)to hook up.This breakout board is focused around Renesas' FS3000-1005， a surface-mount air velocity module with a range of 0-7.2m/s(0-16.2mph). It utilizes a MEMS thermopile-based sensor， features a digital output with 12-bit resolution and comprises a "solid" thermal isolation technology and silicon carbide coating to protect it from abrasive wear and water condensation.We've written an Arduino library to help you get started quickly. You can download the library through the Arduino library manager by searching 'SparkFun Air Velocity' or you can get the GitHub repo as a .zip file and install the library from there.The SparkFun Qwiic Connect System is an ecosystem of I2C sensors， actuators， shields and cables that make prototyping faster and less prone to error. All Qwiic-enabled boards use a common 1mm pitch， 4-pin JST connector. This reduces the amount of required PCB space， and polarized connections mean you can't hook it up wrong.Get Started with the Qwiic Air Velocity Sensor BreakoutFeaturesI2C address：0x28Air flow speed：0 - 7.23 m/sec(0 - 16.17mph)Accuracy：5 % of full scale flow range12-bit resolutionInput Voltage：2.7-3.3VAverage current draw：10mA

DescriptionProduct Restrictions：To access certain features of the ATECC608A， users will need to contact Microchip and sign an NDA contract to obtain the complete datasheet. Due to the required NDA - technical support， an Arduino library， and hookup guide are not provided for users on this product.The SparkFun ATECC608A Cryptographic Co-processor Breakout allows you to add strong security to your IoT node， edge device， or embedded system. This includesasymmetricauthentication，symmetricAES-128 encryption/decryption， and much more. As stated above， the ATECC608A has limited Arduino support and the complete datasheet is under NDA with Microchip.This breakout board includes two Qwiic ports for plug and play functionality. Utilizing our handy Qwiic system， no soldering is required to connect it to the rest of your system. However， we still have broken out 0.1"-spaced pins in case you prefer to use a breadboard. The ATECC608A chip is capable of many cryptographic processes， including， but not limited to：Creating and securely storing unique asymmetric key pairs based on Elliptic Curve Cryptography(FIPS186-3).AES-128：Encrypt/Decrypt， Galois Field Multiply for GCMCreating and verifying 64-byte digital signatures(from 32-bytes of message data).Creating a shared secret key on a public channel via Elliptic Curve Diffie-Hellman Algorithm.SHA-256 HMAC Hash including off-chip context save/restoreInternal high quality FIPS random number generator.Embedded in the chip is a 10Kb EEPROM array that can be used for storing keys， certificates， data， consumption logging， and security configurations. Access to the sections of memory can then be restricted and the configuration locked to prevent changes. Each ATECC608A Breakout ships with a guaranteed unique 72-bit serial number and includes several security features to prevent physical attacks on the device itself， or logical attacks on the data transmitted between the device.A summary datasheet for the ATECC608A is available here. The full datasheet is under NDA with Microchip. You will need to contact them for access to the entire datasheet. Meanwhile， the ArduinoATECCX08 Library currently only supports the ATECC608A with SAMD21 Arduino boards.We do have much more support for the ATECC508A version of this chip. Please check out our ATECC508A Hookup Guide and Arduino Library(which includes six examples). This will get you familiar with the basics of elliptic curve cryptography and signing/verifying data with the ATECC508A version of the chip.Note：The I2C address of the ATECC608A is 0x60 and is software-configurable to any address. A multiplexer/Mux is required to communicate to multiple ATECC608A sensors at the default address when on a single bus. If you need to use more than one ATECC608A sensor at the default address， consider using the Qwiic Mux Breakout.Note：The ATECC608A can be only configured once before it isPERMANENTLYlocked. It is advisable that users purchase multiple boards in order to use other configurations and explore the advanced functions of the ATECC608A.Additionally， this boardIScapable of encrypting and decrypting data. However， to access these additional features， you will need to contact Microchip and sign an NDA contract to obtain the complete datasheet.It is recommended that an SparkFun RedBoard Turbo - SAMD21 Development Board is used with this product due to the buffer size required on the I2C bus.The SparkFun Qwiic Connect System is an ecosystem of I2C sensors， actuators， shields and cables that make prototyping faster and less prone to error. All Qwiic-enabled boards use a common 1mm pitch， 4-pin JST connector. This reduces the amount of required PCB space， and polarized connections mean you can't hook it up wrong.FeaturesOperating Voltage：2.0V-5.5V(Default on Qwiic System：3.3V)Active Current Draw(for ATECC608A)：16 mASleep Current(for ATECC608A)：<150 nAGuaranteed Unique 72-bit Serial Number10 Kb EEPROM Memory for Keys， Certificates， and DataStorage for up to 16 Keys256-bit Key LengthInternal High-Quality FIPS Random Number Generator(RNG)Configurable I2C Address(7-bit)：0x60(Default)

DescriptionThe new PureThermal Mini Pro JST-SR with Thermal by FLIR is a hackable thermal camera for the FLIR Lepton thermal imaging camera core. Just like its PureThermal 2 predecessor， it ships pre-configured to operate as a plug-and-play UVC 1.0 USB thermal webcam that will work with standard webcam and video apps on all major platforms using a JST-SR to USB Cable， or your own custom cable. For developers， its reference firmware and viewer software are open source.It has multiple connection options such as solder straight to the board or a custom cable using the JST-SR port. The PTMini Pro also features four mounting holes， less complex circuitry， and perhaps best of all， USB DFU. This is a development kit ready to be embedded into a production system.Each board comes with a FLIR Lepton 3.5.The FLIR Lepton(R)is a radiometric-capable LWIR camera solution that is smaller than a dime， fits inside a smartphone， and is one tenth the cost of traditional IR cameras. Using focal plane arrays of either 160x120 or 80x60 active pixels， Lepton easily integrates into native mobile-devices and other electronics as an IR sensor or thermal imager. The radiometric Lepton captures accurate， calibrated， and noncontact temperature data in every pixel of each image.FeaturesPureThermal：Compatible with all production FLIR Leptons， including radiometric 2.5 and 3.5 cores9 Hz color video over usb using the USB UVC classSTM32F412 ARM microprocessor - execute on-board image processing without need for an external systemOpen source reference firmware：GroupGets PureThermal GithubWorks with GetThermal - our custom open source thermal video display software for macOS and Linux with radiometric supportDFU over USB using a JST-SR port to USB cable， or a modified USB cable and the through holes.Four mounting holesCompact form-factor ready to be embedded into production systemsFLIR Lepton 3.5：Thermal sensitivity：< 50 mK(0.050℃)Spectral Range：8 - 14 microns(nominal)Long Wave Infrared(LWIR)Resolution：160h×120v pixelsRadiometric Accuracy - High Gain Mode：Greater of +/- 5℃ or 5%(typical)； Low Gain Mode：Greater of +/- 10℃ or 10%(typical)Scene Dynamic Range - High Gain Mode：-10° to +140℃； Low Gain Mode：-10° to +400℃(at room temperature)， -10° to +450℃(typical)Pixel Size：12 micrometersFrame Rate：8.7 Hz(effective)Output Format：User-selectable 14-bit， 8-bit(AGC applied)， or 24-bit RGB(AGC and colorization applied)Horizontal Field of View(HFOV)：57°Lens Type：f/1.1Size(w×l×h)：10.50×12.70×7.14 mmWeight：0.9 gramsPower Consumption：150 mW typical， 650 mW during shutter event， 5mW standbyOptimum Operating Temperature Range：-10℃ to + 80℃

DescriptionGone are the days that you have to worry about silicone weather proofing splitting and breaking on you! These are sealed addressable 1 meter long 5V RGB LED strips that come packed with 60 APA104s per meter. Each of these strips are enclosed by a flexible silicon jacket with an IP65 waterproof rating to protect your precious APA104 LEDs. You will be able to control each RGB LED individually giving you the ability to create cool lighting effects for your car， fish tank， or perhaps under cabinet lighting in your kitchen! These LED strips are compatible with similar WS2812 and SK6812 addressable LED's.Note：These come in 1m segments on a reel. They are preterminated with 0.1" spaced 3-pin connectors as well as a 2 wire power connector， as shown in the pictures.FeaturesFlexible LED strip with external control for each LED pixelHigh brightness， full-color and fully addressable(cascade， chasing and scanning)Maximum length of 5 metersExample uses include architectural， landscape， and decorative lighting

DescriptionLIDAR has never looked so good! This is the LIDAR-Lite v3HP， a compact， high-performance optical distance measurement sensor from Garmin(TM). The LIDAR-Lite v3HP istheideal optical ranging solution for drone， robot， or unmanned vehicle applications. Each sensor is housed in a durable， IPX7-rated housing and includes all the core features and user configurability of the popular LIDAR-Lite v3.The v3HP is very similar in function to that of the v3 but it can now sample faster at rates greater than 1kHz(where as the v3 is only capable of up to 500Hz). Another improvement is that this v3HP model is more power efficient with current consumption rates 40mA less than the v3(that's 65mA as opposed to 105mA while idle， and 85mA instead of 130mA while acquiring).Each LIDAR-Lite v3HP has a range of 1m to 40m and features an edge-emitting， 905nm(1.3 watts)， single-stripe laser transmitter， 8m Radian beam divergence， and an optical aperture of 12.5mm. This version of the LIDAR-Lite still operates at 5VDC(6V max)with a peak power of 1.3W and still possesses an accuracy of +/- 2.5cm at >2m. On top of everything else， the LIDAR-Lite is user-configurable， allowing adjustment between accuracy， operating range and measurement time and can be interfaced via I2C or PWM with the attached 200mm cable.Note：CLASS 1 LASER PRODUCT CLASSIFIED EN/IEC 60825-1 2014. This product is in conformity with performance standards for laser products under 21 CFR 1040， except with respect to those characteristics authorized by Variance Number FDA-2016-V-2943 effective September 27， 2016.Get Started with the LIDAR-Lite v3HP GuideFeaturesResolution：1 cmTypical accuracy：+/- 2.5cm at distances greater than 2 meters(Refer to operating manual for complete operating specifications)Range：1m to 40mUpdate rate：Greater than 1kHzInterface：I2C or PWMPower(operating voltage)：4.75-5VDC； 6V MaxCurrent consumption：65ma idle； 85ma during acquisitionOperating temperature：-20℃ to 60℃Laser wave length/Peak power：905nm/1.3WBeam divergence：8m RadianOptical aperture：12.5mmWater rating：IPX7Unit dimensions：24.5mm×53.5mm×33.5mm(1.0in×2.1in×1.3in)Weight：34g(1.2oz)

DescriptionThis is the SparkFun RFM69 Breakout， a small piece of tech that breaks out all the pins available on the RFM69HCW module as well as making the transceiver easy to use. The RFM69HCW is an inexpensive and versatile radio module that operates in the unlicensed ISM(Industry， Science and Medicine)radio band. It's perfect for building inexpensive short-range wireless networks of sensors and actuators for home automation， citizen science and more.This RFM69HCW operates on the 434MHz frequency and is capable of transmitting at up to 100mW and up to 300kbps， but you can change both of those values to fit your application. For example， you can maximize range by increasing the transmit power and reducing the data rate， or you can reduce both for short-range sensor networks that sip battery power. At full power and with simple wire antennas， we can get messages from one side of a large office building to the other through numerous internal walls. In open air you can reach 500 meters or more. With more complex antennas and modulation schemes， similar parts have successfully transmitted from space to the ground(by very smart amateur radio enthusiasts； your mileage may vary)!The RFM69HCW uses an SPI(Serial Peripheral Interface)to communicate with a host microcontroller， and several good Arduino libraries are available. It supports up to 256 networks of 255 nodes per network， features AES encryption to keep your data private， and transmits data packets up to 66 bytes long.SparkFun sells two versions of the RFM69HCW：a 915MHz version and this 434MHz version. Although the ISM band is license-free， the band itself is different in different areas. Very roughly， 915MHz is for use in the Americas， and the 434MHz version is for use in Europe， Asia and Africa. Check your local regulations for other areas.Get Started with the RFM69HCW Hookup GuideFeaturesTransmit power：-18dBm(0.016mW)to +20dBm(100mW)in 1dBm stepsReceive sensitivity：down to -120dBm at 1.2kbpsModulation types：FSK GFSK MSK GMSK OOKBit rates(FSK)：1.2kbps to 300kbpsVoltage range：1.8V to 3.6VCurrent consumption：0.1uA sleep， 1.25mA standby， 16mA receive， 130mA transmit(max)Encryption：AES 128-bit(optional)Packet buffer(FIFO)：66 bytes0.8"×1.1"

DescriptionThe TFMini-S Micro LiDAR Module is a ToF(Time of Flight)LiDAR sensor capable of measuring the distance to an object as close as 10 centimeters(+/- 6cm up to 6m)and as far as 12 meters(+/-1% starting at 6m)! As with all LiDAR sensors， your effective detection distance will vary depending on lighting conditions and the reflectivity of your target object， but what makes this sensor special is its size. Measuring only 42x15x16mm， the TFMini-S allows you to integrate LiDAR into applications traditionally reserved for smaller sensors.TFMini-S is a single-point ranging LiDAR based on TFmini upgrade. The blind zone is shortened to 10cm， the outdoor performance and accuracy of different reflectivity are improved， it can achieve stable， accuracy， sensitive and high frequency range detection.Important：This product does not use laser light for ranging. Instead it contains an LED and optics. Many such systems are being marketed under the name "LiDAR，" although it may be more appropriate to think of this device as a "Time-of-Flight Infrared Rangefinder". It differs significantly from traditional IR rangefinders in that it uses ToF to determine range and not triangulation ― as is performed by the Sharp GP-series devices.FeaturesOperating Range：0.1m～12m@90%Reflectivity0.1～7m@10% Reflectivity0.1m～12m@90%Reflectivity(70Klux)0.1～7m@10% Reflectivity(70Klux)Accuracy：±6cm@(0.1-6m)±1%@(6m-12m)Distance Resolution：1cmFrame Rate：100HzAmbient light immunity：70KluxOperating Temperature：0℃～60℃Light source：VCSELCentral wavelength：850nmPhotobiological safety：Class1(EN60825)FOV：2°2Supply voltage：5V±0.1VAverage current：≦140mAPower consumption：≦0.7WPeak current：200mACommunication level：LVTTL(3.3V)Communication interface：UART / I2CDimension：42mmx15mmx16mm(LxWxH)Housing：PC/ABSStorage temperature：-20℃～75℃Weight：5g±0.3gCable length：10cm

DescriptionThis is a two pack of Zrn coated flat mills from Carbide 3D that are perfect for fabricating with aluminum. Each mill in this pack features a cutting and shank diameter of 0.25 inches and a cutting length of 0.75 inches. These cutters really are great for precision 3D machining and fabrication.These cutters are coated with Zirconium Nitride(Zrn). This is a specialty coating which makes it most suitable for temperature sensative materials. ZrN had excellent corrosion-resistance， lubricity and hardness to suit many applications. This coating has a unique ability to reduce the build-up edge on cutting tools which results in a better surface finish. ZrN works well for machining Titanium and Aluminum Alloys， Nickel， Brass， Copper， Cast Iron and Zinc. Each cutter is made of solid carbide to ensure long lasting use.FeaturesCutting Diameter：0.25"Cutting Length：0.75"Shank Diameter：0.25"3 Flute， center cutting2.5" Overall Length

DescriptionStandard frequency crystals - use these crystals to provide a clock input to your microprocessor. Rated at 20pF capacitance and +/- 50ppm stability. Low profile HC49/US Package.

DescriptionStandard 'Watch' or Real-Time-Clock crystal. 32.768kHz means it is precisely half of a 16-bit counter. Start counting at 0x8000(or 32768). When the counter rolls over from 65535 to 0， then you know that exactly one second has passed. Reset the interrupt， reset the counter， and start counting again! Rated at 12.5pF load capacitance， 35K ohm max(18K ohm typical)series resistance， and +/- 20ppm stability. Small cylinder package.