Saturday, September 23, 2017

Crossing the Great Canadian Electric Vehicle Desert

I recently returned from a three week trip crossing Canada in a Tesla Model S. The journey began in the heart of Silicon Valley and followed the West Coast of the United States until reaching Vancouver. I then travelled east on the Trans-Canada Highway until reaching the Greater Toronto Area where I was born and raised. After spending some quality time with family and catching up with old friends I returned to California on the Tesla Supercharger Network, crossing through the Rocky Mountains of Colorado.

Green: Charging Stops | Red: Rest Stops | Purple: Trip Start/Finish
It was an incredible trip and certainly takes first place for the longest of my road trips. I faced challenges crossing Canada due to the lack of charging infrastructure. With perseverance, resourcefulness and patience I was able to complete the trip without requiring a tow (though I did have a close call in Northern Ontario).

Tesla Model S in Rocky National Park, Colorado
Along the way I met some incredible people. One fellow performed his own EV conversion on an older model Porsche. Another built his own experimental aircraft. I was graciously invited into the home of a Tesla owner in Thunder Bay, Ontario who was happy to lend a charge and share a meal. The trip was enlightening because it was off the beaten path and allowed an opportunity to meet people who live their life just a little differently than the way I live my own.

Driving through the Rockies in Alberta

This trip encompassed 12000km (7400mi) of driving and consumed more than 2.2MWh of energy spread out over 140+ hours of driving. The trip across from Silicon Valley to Toronto took 8 days, 3 of which were spent navigating Northern Ontario. It was an exercise in patience but the prize of being just one of a few drivers to complete this route in an electric vehicle is unequivocally worth it.

Sunday, January 8, 2017

pwrusbctl: A command-line tool for controlling USB-connected power strips

Over the past few days I wrote a command-line tool for controlling and monitoring PowerUSB-branded power strips. These are clever devices that connect to a computer via USB and allow power monitoring and controlling the state of the outlets. I decided to call it pwrusbctl and you can view the code on GitHub.

The company that sells them offer a binary blob driver, but I wanted something that I could extend and modify. I also want it to work with my RaspberryPi.

PowerUSB Basic connected to a RaspberryPi
I used HIDAPI as an abstraction over HID which makes the codebase portable. It has been tested to work on Linux and Mac OS. You can find more documentation in the README on GitHub. Here is an example of the output:
[andrew@andrew-rpi-1 pwrusbctl]$ ./pwrusbctl --reset_charge_accumulator --device_info --log_indefinitely --power --energy --interval 2000000
Found PowerUSB device type: Basic
Power: 32.200001W
Energy: 0.000000kWh
Power: 32.200001W
Energy: 0.000537kWh
Power: 27.599998W
Energy: 0.000537kWh
Power: 27.599998W
Energy: 0.000537kWh
Power: 50.599998W
Energy: 0.000537kWh
Power: 172.500000W
Energy: 0.000537kWh
Power: 342.700012W
Energy: 0.000537kWh
Power: 519.799988W
Energy: 0.000537kWh
Power: 545.099976W
Energy: 0.000537kWh

Saturday, December 31, 2016

Extreme Long Range Electric Longboarding: 56km on a Boosted Board

I just returned from a 56km Boosted Board ride. I toured the bike trails along the Upper/Lower Crystal Springs Reservoirs and San Andreas Lake here in the San Francisco Bay Area. This is a new record for me. My previous range record was 27km on a single charge.

Boosted Board with external battery in my backpack :]
To achieve this I used a very large and custom designed lithium-ion battery pack. I tossed it in my backpack and connected it to the Boosted Board where I had previously made a modification to expose the internal battery voltage rail. This pack is arranged in a 10S6P (10-series, 6-parallel) configuration. It has a rated capacity of 21Ah at 37V nominal or roughly 777Wh. The internal battery of the Boosted Board has a rated capacity of 99Wh.

This battery pack is designed to attach to a custom designed board that I have been working on but is not ready for prime time yet. Below is a sneak preview of the board I am working on. I have decided to name it Voyager as one of the design goals has been to prioritize range.

10S6P battery mounted to Voyager with custom charging cable attached
Continue reading to learn more about my new record and construction of this battery pack. There are also more pictures of Voyager at the bottom of this post.

Sunday, November 6, 2016

ichargermon: a Linux/Mac iCharger monitoring tool

I use an iCharger 1010B+ to charge a few batteries for my electric skateboard. I also top up the battery in my car from time to time. I thought it would be nice to keep track of the charging progress so I wrote a small tool to parse logs that are output over UART and format them into a human-readable format.

I named the tool ichargermon. Feel free to send a pull request!

The project is written in C/C++ and has no external dependencies at this time. If I decide to support more advanced iChargers I will add libusb as a dependency.

Charging a small 3S1P battery pack
I also have an iCharger 4010Duo that I would like to add support for. The 4010Duo implements a much more rich protocol (MODBUS) that supports both remote monitoring and control.

Anyway, for now here is an example of the output. Thanks for reading!
Input voltage:    15.163V
Battery voltage:  40.165V
Battery amps:     0.990A
Internal temp:    30.300C
Cell 0 voltage:   4.009V
Cell 1 voltage:   4.010V
Cell 2 voltage:   4.012V
Cell 3 voltage:   3.998V
Cell 4 voltage:   4.014V
Cell 5 voltage:   4.014V
Cell 6 voltage:   4.014V
Cell 7 voltage:   4.014V
Cell 8 voltage:   4.017V
Cell 9 voltage:   4.019V

Thursday, February 11, 2016

VGA Generation with Freescale i.MX23 + Linux

I have long wanted to become more well acquainted with the Linux kernel and finally decided to bite the bullet. I ordered an iMX233-OLinuXino-MAXI from Olimex to tinker with. The Freescale i.MX23 processor is noteworthy because it is available in an LQFP-128 package which means it can be installed on a PCB by hand with inexpensive tools and a steady hand. It is also a great platform to learn with because it is well supported by the upstream kernel and has documentation available without signing an NDA.

The first thing I did was modify the device tree (DTS files) to enable the LCD controller and tuned it to generate a VGA signal. I built a simple R/R2 DAC on a breadboard and was able to view the image on an LCD monitor.

The projected image next to my workstation
All of this was completed under Arch Linux ARM which provides a minimal base image and root filesystem upon which a large number of packages have been ported to run on ARM. This has been a great learning experience and I plan to continue working with this chip more.

Hackaday, it doesn't quite like the 640 width
Continue reading to see the very minor changes I made to the kernel and how I wired it  all up.

Tuesday, January 26, 2016

MikMod on STM32F4

Over the past couple of days I have ported libmikmod to run on an STM32F407. This is a very memory constrained environment with only 128kB of RAM but I am able to play some rather complex MOD and XM files that are in the range of 60kB in size. I had to patch libmikmod slightly and write a new audio output driver to make all of this happen.

MikMod on STM32F4 Hardware :]
The audio quality is quite good. I currently have MikMod configured to render at 44.1kHz in mono. I could likely render in stereo but I would be limited to smaller MOD and XM files due to the increased memory usage. Here is a video that mainly shows the audio quality as captured by my camera.

The video below contains a little more technical detail, demonstration of boot and loading different audio files.

Monday, November 9, 2015

Long Range Electric Longboarding

I bought a Boosted Board back in August of this year while living in New York City. It was an awesome purchase. It is fun to ride and I could often beat the subway to my destination on shorter trips. I have since moved to Silicon Valley and find the range to be lacking slightly. The board gets approximately 7 miles of range out of the box and my office is 10 miles from home.

My Boosted Board shortly after purchase.
I added 288Wh of high-discharge lithium-ion batteries to the 99Wh of batteries that came with the board. I was inspired by the Portable Electric Vehicle Youtube Channel.  During the first test ride I was able to ride more than 13 miles before stopping. The fuel gauge on the remote showed more than 20% of battery remaining.

My Boosted Board after the battery upgrade :]
During this process I also designed a custom lighting system based on WS2812 LEDs and an Arduino Mini Pro.

These LEDs are bright!

Sunday, November 23, 2014

Flir Lepton Thermal Imaging Sensor + Gameduino 2

I recently got my hands on a pair of Flir Lepton thermal imaging sensors and have spent the last week bringing them online in my spare time. These are absolutely incredible devices that I believe will pave the way to consumer devices incorporating thermal imaging cameras. The footprint of the camera module (and optical assembly) is about the size of a dime. The resolution is 80x60 at 14bpp which is remarkable despite sounding low.

Thermal Andrew :]
I have successfully implemented a driver for the Lepton module and displayed frames on an LCD. This is all running on an STM32F4 processor on a Nucleo board. Attached to it is a Gameduino 2 which incorporates the FT800 graphics processor. I have implemented my own colorization and min/max scaling before uploading the frames to the GPU.

Front System Overview
I have used some simple jumper wires to interface with this camera. This setup is running at 21MHz with no issues. I am using a breakout board provided by Pure Engineering. You can pick up one from Tindie if you are interested. The Lepton module can be ripped out the Flir One iPhone accessory for now.

Rear System Overview and Second Camera (future project ;])
I wrote my own driver for the Lepton core and the FT800 graphics processor. Continue reading for more details!