Data-logging and telemetry, a market research
Before embarking on a new project it is advised to do some research; specially to see if somebody else has done it already and how. That will save us some precious time later during development.
What I’d like to do in this post is to make a brief list of COTS telemetry and data-logging equipment features, mainly focusing on go-karting telemetry which are cheaper than race car specific equipment. A typical digital dash on a kart will show at least lap time, engine RPM and engine temperature. The table below is just a sample of what can be found in the mid-range of products from two well-known manufacturers.
|MyChron3 Plus||MyChron3 Gold||MyChron3 Extreme||PRO+ LV||AStrO LV|
|Analog inputs||2||2||4 (2 free)|
|–Temperature||2 analog||2 analog||2 analog||2 analog||4 analog|
|–Pressure sensor||—||—||analog||—||2 analog|
|Logging rate||10 Hz||10 Hz||10 Hz||—||—|
|Memory||512 kB||2 MB||2 MB||24 h||24 h|
|Batteries||6 AAA||6 AAA||6 AAA||2 AA||2 AA|
The MyChron4 substitutes the MyChron3 (discontinued), but uses the same sensors, leads and beacon, though with 1 MB of memory for data-logging purposes. If you are not to build your own data-logging and telemetry system, I found that Mikko Nassi has posted a comprehensive buying guide in his Introduction to Kart Data Acquisition.
The Arduino Due has a total of 54 digital I/O pins (of which 12 provide PWM output) and 12 analog input pins and the microcontroller runs at 84 MHz. I think that’s more that enough to replicate the capabilities of any mid- to high-range data-logger.
Another well known data-logging and telemetry equipment vendor is MoTeC; but their equipment is too expensive to suit Go Karts, reason why they haven’t chased this market yet. In the table below you may see a comparison chart of some of their products as found on their website. Their features might give us some ideas on what components to add to our data-logger as to broaden its capabilities and functionality.
|Data Acquisition Comparison Table||C125||CDL3||SDL3||ADL3 / EDL3|
|Analogue voltage||Optional 6||Optional 4||8||10|
|Analogue temperature||Optional 2||Optional 2||4||4|
|Digital||Optional 2||Optional 2||2||4|
|Speed||Optional 3||Optional 3||4||4|
|Wideband Lambda||Via PLM or LTC||via PLM or LTC||via PLM or LTC||via PLM or LTC|
|Expansion units||E888/E816 (full functionality)||E888 (8 thermocouples only)||E888 (8 thermocouples only)||up to 2 x VIM and|
|2 x E888/E816|
|Data acquisition and telemetry|
|Data logging memory||Optional||Optional 8 MB||Optional 16 MB||16 MB|
|120 MB||or 120 MB||Optional 250 MB|
|Logging rate||1 – 500 Hz||1 – 500 Hz||1 – 500 Hz||1 – 1000 Hz|
|Analysis using i2 Standard||Optional||Optional||Optional||yes|
|Analysis using i2 Pro||Optional||Optional||Optional||Optional|
|Telemetry||table cross||table cross||table cross||Optional|
|Remote logging||table cross||table cross||table cross||Optional|
|Type||Ultra Bright Colour||Reflective Mono LCD||Reflective Mono LCD||Reflective Mono LCD on ADL3; No display on EDL3|
|Backlight||yes||yes||option||Optional on ADL3|
|not on EDL3|
|Display modes||3||3||3||3 on ADL3|
|RS232||2 x Receive||yes||yes||yes|
|1 x Transmit|
|Digital, Switched, PWM||4||4||4||4|
|Expansion units||1 or 2 x E888/E816||—||—||1 or 2 x E888/E816|
|more on…||C125||CDL3||SDL3||ADL3 / EDL3|