December 2019 Hodgepodge

 New "World's fastest compact microcomputer"

The Teensy 4.0  $19.95
             ARM Cortex-M7 processor at 600 MHz, contained in NXP iMXRT1062 chip

  • Executes 2 instructions at a time (about 40% to 50% of the time compiled by TeesyDuino),   Employing tightly coupled split memory with 2 64 bit paths..
  • FPU handles Double Integers as well as Floats
  • 1024K RAM (512K is tightly coupled) 
  • 2048K Flash (64K reserved for recovery & EEPROM emulation) 
  • Lots of interfaces
 6.6 X faster than ESP32 in one benchmark. (331 X faster than Arduino AVR Mega)

 The Teensy board line appears to be the product of a one man operation run by Paul Stoffregen, he seems quite competent and is active on the support forum, his store is a little behind, it took some hinting to find the sales page for the Teensy 4.0.
 It works with Arduino IDE his variation called TeesyDuino, using an installer that apparently taps into the IDE at lower level.

Hackaday review





Seeedstudio recently introduced the ROCK PI boards using a RK3399Pro SOC with Dual Cortex-A72, 1.8GHz and quad Cortex-A53, frequency 1.4GHz and a massive heatsink.  Models are available with 4, 6 & 8Gb of RAM for $99 to $169.

They describe the board as being for AI applications (one of a bunch of different AI boads offered by Seeed)  I have not seen bench marks, and don't know who makes it.

This board resembles the Korean board mentioned in another post.

They don't mention the degree of compatibility with actual Raspberry Pi applications, it operates under Debian and Android 8.1.

There's a handy comparison table with specs for:
Rock Pi N10(Model A/B/C)   Raspberry Pi 4B   Jetson Nano


Seedstudio is also carrying the OpenMV4 Cam H7 for $65, a small Machine Vision board.  This board is made by the authors of the the OpenMV software package, which is a MicroPython based counterpart of OpenCV.  The ARM Cortex H7 processor running at 480 Mhz is a big leap in processing power.

The 400Mhz dual risk5 processor on the $20.90 Sipeed boards (with camera and LCD) run a partial implementation of OpenMV, it might have better benchmarks than the H7.

I just noticed a link to the biggest internet marketplace Taobao.com listing of the Sipeed products
Maix Board alone $3.13 USD  (perhaps a clearance price)
MI bare processor module  $6.66 USD
Lichee Zero (minimal Linux board) $1.07 USD



Expressif getting into AI ?

The makers of the popular ESP32 has reportedly making AI their next big development field.  THis is probably due in part due to their products being based on Tensilica-based chips, while most existing IOT AI development is based on ARM processor platforms

They have decently introduced the ESP-EYE board, which doesn't look like anything special on first glance, it looks like one more IOT camera board.  It does have 8 Mbyte PSRAM and a 4 Mbyte flash.





All of the Expressif development boards are listed here








6 Axis robot arm kickstarter  Pledge $1,238 or more for Duo Kit: Gluon 4-Axis + 6-Axis


Uncensored Tower of Hanoi demonstration under Chinese mountains.



Home metal working


Brazing Aluminum (and other soft metals) with flux filled rods

Alumifix , Alumite , Alumaloy & Durafix are brand names for rods that can bond aluminum with a propane torch.

Claims to be "Stronger than base metal"  the butt-welded with a thick bead at the weld demonstrates that the joint is less flexible than the aluminum, but is the first thing to break.

Typical spec:  Melting temperature: < 896°F (480°C)

Propane air-only torch will burn at around 1,995 °C (3,623 °F),


                                        Demonstration with details on surface preparation


                                              5 different tests  most hammering @ 19:45



  Stove Top Metal Casting

 


An Adafruit tutorial  demonstrates how one can cast metal parts at home using low melting temperature allows, recreating a 3D printed part (Positive) from which a mold is made with 2-part silicone. 
                    Tin-Bismuth alloy has a melting temperature  281° F

 He mentions other alloys referred to as: "stovetop casting alloy", "bullet casting alloy", "low melt fusible alloy", and "fishing tackle weight alloy". 





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