For my Hexiwear university research project I’m exploring wireless charing options. I have built a DIY Qi charging station and created a 3D printed enclosure for it:
Qi Charging Transmitter
The Hexiwear device is a great and versatile device with two microcontrollers on it. Developing firmware on a Hexiwear means changing what was originally on it. And sometimes it happens that I’m not sure if the changes are for good. Or that I accidentally destroyed the firmware on the NXP Kinetis KW40 BLE microcontroller :-(. So I had to find a way to restore the original firmware, and this is what this post is about.
Restoring the Hexiwear Firmware with a Segger J-Link
For a research project we are using Hexiwear to measure the effectiveness of teaching and learning. The Hexiwear is used as a networking sensor device in that project. For that project we needed a docking station with wireless capabilities:
Mini Docking Station for Hexiwear
For many of my applications I need to measure a distance. I have used ultrasonic sensors, but there view angle (beam) is not able to detect smaller objects, it very much depends on the object surface and angle, it is slow and not very precise. I have used infrared sensors, but here again it depends on the infrared reflection of the object in range, it depends the amount of reflected light is not really telling much about the distance, and yet IR reflection is subject of material and object targeted.
But there is yet another sensor type to consider: ToF! ToF (or Time-of-Flight) sensors have a built-in LIDAR: The sensor is sending out light pulses and measures how much time it takes for the light to come back. Similar to ultrasonic sensors (see “Tutorial: Ultrasonic Ranging with the Freedom Board“), but instead of ultrasonic it uses an infrared laser light. Or think about a radar system using an infrared laser light.
Vl6180x Breakout Board with tinyK20 (NXP Kinetis K20) Microcontroller-board
The year is coming to an end, the Holiday season is approaching. In case you are looking for a nice present: I have completed my version of a sand clock: a clock writing the time into sand:
Sandclock
If you are interested to build your own version, I have documented the different steps with tips and tricks…
The good thing with failure is: it is an opportunity to learn :-).
So here is a case: For a STEM roadshow (see “MINTomat: World’s Most Complicated Bubble Gum Automata?“), we have produced in a rush an autonomous robot with a shiny printed 3D cover:
Prototyp with LED Effects
How to fascinate kids for technology? Show them that engineering is fun :-). At the Lucerne University of Applied Sciences and Arts we have created the ‘MINTomat’: a robotics system for STEM activities rewarding interaction with bubble gums:
MINTomat
Yes, pretty over engineered compared to a normal bubble gum automata, but that’s part of the fun :-).
It seems to me that not many developers use hardware trace? ARM indicates that maybe only <5% of developers are using trace. Too bad! Why are all the ARM Cortex microcontroller vendors putting a powerful hardware (and complicated!) trace engine into their devices, if only few developers are using it? Seems like a waste of silicon and an unnecessary price adder? Well, hardware trace can be a life saver: Because only with hardware trace the most complicated bugs and problems can be solved. And maybe because only the best are using it ;-).
In this article I proudly present my research how to get instruction trace out of the ARM Cortex-M4 microcontroller on a NXP TWR-K64F120M board with a Segger J-Trace for ARM:
J-TRACE tracing NXP TWR-K64F Board
Command line tools to build applications are great. But productivity goes up if I can use the standard Eclipse environment with GNU tools. This tutorial is about how to use standard and free GNU and Eclipse tools to build my FreeRTOS application for the ARM Cortex-M4 on i.MX7 🙂 :
Eclipse used to build FreeRTOS applications for M4 on i.MX7
My Toradex i.MX7Dual module comes with a preflashed Linux distribution (see “Tutorial: First Steps with NXP i.MX7 and Toradex Colibri Board“). As with any other things, Linux gets updated from time to time, and Toradex publishes new firmware. In this article I’m documenting how I can update Linux in the external FLASH on that module.
NXP i.MX7Dual Module
MCU on Eclipse 