The eChook Nano is an open source Arduino and Android based data logging and telemetry solution designed specifically for cars competing in Greenpower events.
While so many data logging options are black boxes, the eChook nano uses simple circuits that are covered in GCSE and A Level electronics curriculums, and well commented Arduino code to make the system as understandable as possible.
This video shows an early prototype of the eChook Nano running at Rockingham
There are three elements to the eChook; the hardware and sensors on the car, an Android app, eChook Companion, that receives the data over bluetooth, logs it and optionally uploads it (data connection required) to the cloud for viewing in near real time from anywhere with an internet connection and the website for viewing live data.
Note: An Android phone with the eChook Companion app is required in the car to log the data!
The eChook Nano is supplied as a self-assembly kit of parts containing:
- eChook nano PCB
- Arduino Compatible microcontroller
- All components required to build the board
- A selection of sensors - Note: current sensor not shown in images but is included in the kit
See here for the full list of components and sensors.
Further items you may need include:
- Magnets for triggering on motor shaft and wheel to provide speed reporting. It's recommended to use 3 x 1mm or larger neodymium puck magnets.
- Android phone running android 5 (released 2014) or greater.
- Wire to connect sensors to the eChook
- Printed instructions! These are available online here.
To build the eChook nano you will need:
- Soldering Iron
- A little soldering ability - there’s nothing too fiddly!
- 24v/12v Power Supply (ideally a bench supply with a current limit feature, but Greenpower batteries will do, be sure to use a fuse appropriate for the wiring you have attached though)
- A computer with the Arduino IDE installed to upload the code to the Arduino
The sensors included in the kit will allow you to log:
- Voltage (Total, and of the two batteries individually)
- Motor RPM*
- Wheel RPM/Speed*
- Temperature x2
- Throttle input
- Brake input (on or off)
*Magnets required for triggering are not supplied in this kit - see above.
From these inputs, and augmenting them with sensors on the Android phone, the app will log:
- Amp hours used
- Lap Number (requires GPS to be enabled and a throttle input)
- Gear number and ratio (for cars with multiple gears)
- GPS position
The data is logged in a .csv file which you can share from the eChook app for viewing and graphing in any spreadsheet program.
Note on Telemetry:
Currently the app supports telemetry through the dweet.io website. This works well, but please be aware data is publicly accessible.
We are developing a website for private live data which is expected to be open for beta testing at the start of the 2018 season.
Nathaniel Olsen, Stealth Racing, talks about the eChook Nano:
"I've been racing since 2011 in Greenpower, racing many different cars that I've built but I never had the capability of understanding and predicting the performance of the car before the all important race run and therefore was racing mostly blind. With my new car that I built for the 2016 season, Stealth II, I wanted to maximise the performance of the car and my next step was to understand the limits and how external factors and the setup of car would influence its overall speed and energy consumption.
With the echook nano installed in the car, I was able to extract data that my phone collected throughout the practice runs in the morning where I would vary the gearing setup, starting with my baseline and collect as much information i can get. I would then analyse the current draw, average amp-hours used over a lap and voltage drops for all of gears I would run and decide on the optimum speed and gearing that will last the whole race.
Since using the data logger Stealth II has been performing more consistently and closer to its maximum potential. With my growing collection of data and knowledge, I've been able to arrive at different tracks with a much better idea of what to expect and find my optimum setup quicker than ever before."