paulv @ paulvdiyblogs.net designed and build a transistor curve tracer and documents the process on his personal blog. He writes:
It’s not that I use a Curve Tracer that much, but if you want to categorize or really measure the parameters of a discrete component, there is really no other tool that can do the job well. Of course, there are very simple tools and gadgets available that do a go-no-go test, and even can give you the current amplification factor. I have one of those too, but they are very limited in what they can do. It’s also fun to design something like this, as a mental exercise, which is why I do a lot of these things. I like to design and build Test and Measurement tools.
Bitmain has announced a “Sophon BM1880 EDB” 96Boards CE SBC which features their new Sophon BM1880 AI chip plus dual Cortex-A53 cores running Linux OS. Also available, are the RISC-V MCU and optional Raspberry Pi and Arduino modules. Popular for their vending of bitcoin mining chips and computers, they also have a “Sophon” AI chip business built around the BM1680 and more recent BM1682 Tensor Computing Processor (TPU) AI chips. The board is referred by 96Boards.org as the “Sophon Edge”. The Sophon BM1880 Edge which is an open spec Linux driven SBC will be available at the end of November 2018 for $129, but you can pre-order it now.
Sophon BM1880 Edge
A BM1880-based USB stick and compute module were also announced, among other products. Bitmain joined the steering committee of Linaro’s 96Boards community. The SBC is the latest of Linaro’s family of AI-enabled 96Boards products. These include boards like the Sophon BM1880 EDB and HiSilicon Hikey970 that are fitted with neural network acceleration chips, as well as other boards without such accelerators such as the DragonBoard 920C and Rockchip Rock960, but can still be used for edge AI applications. The Sophon BM1880 EDB is referred to as the first ASIC-based 96Boards.ai product, despite the fact that the BM1880 TPU is an ASIC and not the dual 1.5GHz Cortex-A53 cores that accompany it.
The BM1880 TPU and the EDB boards are built for deep learning techniques, like facial recognition, object detection and recognition, license plate recognition and voiceprint recognition “in real-time on small devices without needing an Internet connection,” according to Bitmain. The BM1880 TPU gives a 1 TOP performance on 8-bit integer operations and up to 2 TOPS with Winograd convolution acceleration, according to Bitmain. The TPU has a scheduling engine, “which supplies extremely high bandwidth data flow effectively to all the tensor processor cores.” The chip incorporates 2MB of memory. The BM1880 is also available in the dual -A53 version, which allows it to be used as the main processor, or as a deep learning co-processor without the -A53 cores. According to Bitmain, the BM1880 can also receive video streams and image data from other hosts and then carry out inference and return the results back to the hosts.
The BM1880 TPU comes with a deep learning model compilers and an SDK. According to Bitmain, deep learning frameworks like Caffe, ONNX, Pytorch, and Tensorflow can be easily ported to the BM1880 platform. It also supports neural network models including CNN, RNN, and DNN. The company says EDB board can support ResNet50, Yolo V2, GoogleNet V1, MobileNet v1/v2, SSD300, Alexnet, and VGG16. Apart from its processors, the Sophon BM1880 EDB (Sophon Edge) board is quite a standard 96Boards CE SBC, except for the fact that it’s a headless board without video ports and lacks the usual 60-pin high-speed connector. The 96Boards compatible 40-pin connector is presumably where mezzanine boards can be added for the announced Raspberry Pi and Arduino development modules.
Sophon Network Module
The board is a first of its kind, with a RISC-V companion MCU. The unidentified chip is presumably an MCU-like RISC-V part for real-time processing, probably designed by Bitmain. This is a high clock rate for an MCU, so it’s likely an alternative Linux chip in addition to the dual -A53 block. A boot switch is listed in the hardware manual that lets you switch between Arm and RISC-V for booting. The Sophon BM1880 EDB is fitted with 1GB LPDDR4, 8GB eMMC, and a microSD slot. The board offers GbE, WiFi, and Bluetooth for networking, as well as 3x USB 3.0 host ports and micro-USB and JTAG debug interfaces. Bitmain has also announced a USB-connected Neural Network Stick (NNS) implementation of the BM1880, which is much like Intel’s Neural Compute Stick and Google’s Edge TPU Accelerator. A 38 x 38mm Neural Network Module (NNM) based on the BM1880 is also available. Neither appears to offer the dual -A53 cores for independent Linux operation. Both need connected X86_64 computers running Ubuntu (NNS) or Ubuntu or Windows (NNM).
Bitmain Neural Network Stick
Bitmain also announced a 19-inch 2U Sophon AI Server SA3 rackmount computer, which integrates three processing units, each with 6x of the earlier BM1682 processors, for 18 processors overall. The system has an unnamed quad-core processor (probably an Intel Core) that supports Red Hat, CentOS, or Ubuntu distributions.
Specifications listed for the Sophon BM1880 EDB (Sophon Edge) include:
Processor — Bitmain BM1880 TPU combined with 2x -Cortex-A53 cores @ 1.5GHz and 750MHz RISC-V chip
Sample overcurrent detection circuit from Texas Instruments. Click link below to download PDF.
This is a unidirectional current sensing solution generally referred to as overcurrent protection (OCP) that can provide an overcurrent alert signal to shut off a system for a threshold current and re-engage the system once the output drops below a desired voltage lower than the overcurrent output threshold voltage.
2 Channel Relay Shield for Arduino UNO is a simple and convenient way to interface 2 relays for switching applications in your project. The board has been designed using large current relay that can handle a load up to 30Amps. Relay circuit is optically isolated to prevent any kind of EMI noise. The board directly seats on Arduino Uno. Project requires 12V DC supply, Relay-1 can be controlled using digital pin D12 of Arduino and Relay-2 interfaced to digital pin D2 of Arduino, J1 and J2 solder jumpers provided in case of Arduino and Relay board to be power up from same supply line. LED D2 and LED D4 indicate the Relay ON/OFF operations. Open the jumpers J1 and J2 in case of complete isolation required.
Specifications
Input: 12 VDC @ 160mA
Output: Two SPDT relay
Relay specification: 30 A /230V
Screw Terminal to supply Arduino
CN3 Power Input to Relay Board
Trigger voltage input TTL level
Digital Pin D12 Connected to Relay 1 and D2 to Relay 2
Header connector for connecting power and trigger voltage
LED on each channel indicates relay status
Power Battery Terminal (PBT) for easy relay output connection
The powerful, tiny power monitor shield for your Arduino Nano.
Constantly and completely monitor your Arduino project’s power consumption with the PowMeter shield. This versatile solution replaces up to four multimeters with a ten gram device.
Advantages of PowMeter Nano:
A very small footprint. The shield attaches directly to your Nano, adding only 23 millimetres in length
Allows you to monitor USB voltage and current when powered through the USB port
Also allows you to monitor power consumption separately on a VIN MON pin
Peripheral power can be metered via the VAUX pin
It does not consume any of your project software resources, thanks to the onshield MCU
The shield draws less then 10 mA
All components communicate through I2C. This means you can take actions inside your own program depending on current or voltage values retrieved from the components
Good measurement precision
You can also use the onshield OLED for your own project
The OLED screen can be installed on either side of the board
Reasonable cost
Specifications
Current measurement error: less than 1% + 1 mA
Current band: 1 mA – 4000 mA
Current resolution: 0.2 mA
Voltage measurement error: less than 1% + 0.01 V
Voltage band: 0 – 24 V
Voltage resolution: 10 mV
Display resolution: 3 to 4 digits
Shield current draw: ~10 mA
High side or low side measurement: when used as a Nano Shield, measurement is on the high side
Felix designed a precision Auto-ranging nanoAmp ammeter with loads of features. He writes:
CurrentRanger is a nanoAmp current meter featuring auto-ranging, uni/bi-directional modes, bluetooth data logging options and more.
It is a highly hackable and affordable ultra low-burden-voltage ammeter, appropriate for hobby and professional use where capturing fast current transients and measurement precision are important.
Here are some of the features of this instrument which sets it apart:
Low noise zero-offset with 3-ranges (1mV output per nA/µA/mA)
Low input burden voltage, high precision & bandwidth analog outputs
Increased flexibility and usability with several input and output terminal options
Auto-ranging capable
Use standalone with a small OLED display or with a multimeter/oscilloscope
Ultra fast range switching between any ranges (even nA to mA) without any glitching/bouncing of a mechanical switch
Low Pass Filter mode – very useful to capture low noise signals on oscilloscopes
Unidirectional mode – most used mode in measuring DC currents ranging from [0, 3.3A]
Bidirectional mode – split supply biasing allows AC currents measurement ranging from [-1.65A, 1.65A]
LiPo battery powered – long life and extended measurement range
Auto-power-off
Full digital control for power & range switching via touch pads
OLED display option to read output with usable precision
Datalogging possible via Bluetooth serial module
SAMD21 Cortex M0+ powered, change firmware to your needs
Optional buzzer for audible feedback
CurrentRanger – Auto-ranging current meter – [Link]
Spresense is a compact development board based on Sony’s power-efficient multicore microcontroller CXD5602. It allows developers to create IoT applications in a very short time and is supported by the Arduino IDE as well as the more advanced NuttX based SDK.
Integrated GPS – The embedded GNSS with support for GPS and GLONASS enables applications where tracking is required.
Hi-res audio output and multi mic inputs – Advanced 192kHz/24 bit audio codec and amplifier for audio output, and support for up to 8 mic input channels.
Multicore microcontroller – Spresense is powered by Sony’s CXD5602 microcontroller (ARM® Cortex®-M4F × 6 cores), with a clock speed of 156 MHz.
Professional development with the speed of Arduino IDE
Spresense development board is created for professional development. As a developer you have the choice of using the Arduino IDE or going for the more advanced route of the extended API based on the NuttX SDK. With Spresense there is no trade-off between short development time and a great end solution.
There will be a range of add-on module boards to equip the main board with the required features needed for each use case, such as BLE, camera module and accelerometer sensors. Additionally the Spresense Extension board makes the Spresense development board compatible with selected Arduino shields.
Powered by Sony’s CXD5602 microcontroller
Despites its compact footprint of only 6.5 x 6.5 mm, Sony’s CXD5602 microcontroller runs 6 ARM Cortex-M4F cores with a clock speed of up to 156MHz and has an integrated GPS. Thanks to the FD-SOI (Fully Depleted Silicon On Insulator) production process, the CXD5602 chip is very power efficient which enables battery dependant use cases. The CXD5602 microcontroller is available for volume orders in case your company is interested in developing your customized PCB solution.
You can buy Spresense development board for ~60€ here.
[update 22/11/2018] hackster.io is giving away 100 @SonyDevWorld Spresense boards to the best project ideas submitted by 6/12/2018. Apply now! The top twelve project submissions using the new Sony Spresense Board will be awarded some nifty prizes, including a top-of-the-line PS4 Pro & VR Bundle!
David Johnson-Davies designed a GPS module that decodes the NMEA sentences on ATtiny841, and this also runs the I2C slave routine. He writes:
This is a compact GPS module with an I2C interface, making it easy to read the GPS parameters from another project without needing to worry about parsing the NMEA sentences. It’s a PCB-mounted version of my earlier project I2C GPS Module:
As an example of using the module I also describe a GPS mapping application, that plots a map of your route on an OLED display.
I based the PCB on the GlobalTop Technology FGPMMOPA6C GPS module, also known as the GTPA010 [1], and these are available from Aliexpress [2]. It should also work with more recent versions of that module, such as the PA6H available from Adafruit [3]. The GPS module is rated at 3.3V so I included a 3.3V regulator on the board so you can power the board from 3.3V or 5V.
The Arrary 3711A can sink 300W with a maximum load current of 30A and maximum load voltage of 300V. It can be used in constant current, constant power or constant resistance mode and can be controlled remotely via an RS232 interface. The entire unit is actually quite compact given the amount of power it is capable of dissipating. This can be largely attributed to the efficient forced-air cooling system it uses. There are four fans all together. Two are sitting at the bottom of the chassis that sucks in air. The air then flows through the heatsinks and the hot air gets blown out from the back via another two fans.
Teardown of an Array 3711A 300W DC electronic load – [Link]
The Raspberry Pi 3 B+ is likely the most popular maker board available today at $35, but it just got a little brother, the Raspberry Pi 3 Model A+.
Raspberry Pi.org announced a new smaller and cheaper board of the RP3 series. You can now get the 1.4GHz clock speed, 5GHz wireless networking and improved thermals of Raspberry Pi 3B+ in a smaller form factor, and at the smaller price of $25.
In order to decrease the price by $10, they obviously had to cut some features. We lost the “Gigabit” Ethernet port, memory dropped to 512 MB RAM instead of 1GB, and there’s only one USB port. There also some invisible changes with improved USB mass-storage booting and improved thermal management.
Want to see benchmark results of various Raspberry Pi boards? Gareth Halfacree has a great article on this aspect, comparing Raspberry Pi 3 Model A+ with other RPs.
Raspberry Pi 3 A+ Thermal Photograph – photo: Gareth Halfacree
Raspberry Pi 3 Model A+ incorporates most of the neat enhancements we made to its big brother, and features:
A 1.4GHz 64-bit quad-core ARM Cortex-A53 CPU
512MB LPDDR2 SDRAM
Dual-band 802.11ac wireless LAN and Bluetooth 4.2/BLE
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