Doug's PakTrakr with Zaurus · 4 July 07
Back in May we featured Electric Vehicle Links to the PakTrakr and to Doug’s Karmann Ghia conversion site. Doug wrote back recently that he’d gone ahead and purchased a PakTrakr for his Ghia EV. Not only that, but he got out an old Sharp Zaurus, dusted off his programming tools (well, I don’t know if they were really all that dusty, just trying for a poetic effect here), and set to work on making a cool display for all of that lovely PakTrakr data.
(click thumbnail for full-sized snapshot of the Zaurus screen)
First off a little background on the PakTrakr.
PakTrakr is a small add-on to your EV (or I suppose anything with a pack of batteries) that features a two-line LCD that displays:
- Pack state of charge
- Individual battery voltages
- 30-day logged data
- Battery Voltages
- Amps/Watts (with optional sensor)
- Battery bay temperature
It also features text alerts for various failure and warning conditions. The base unit will monitor up to six batteries, with optional remotes to extend the monitoring up to twenty four batteries. All in all it looks like a great device for EVs.
The PakTrakr has a serial port, the Zaurus has a serial port, so Doug decided that with all of this groovy data coming out of the PakTrakr he’d could do even more calculations and have an even bigger and better display. Among the gems he added: “live” cost of driving, kiloWatts, kiloWattHours, pack state of chrage, individual battery charge, etc..
Here’s some full sized simulator snapshots of his program’s screens (from the QT designer tools):
Click the thumbnail to get a larger view of the Zaurus and PakTrakr installed in eGhia, his electric car.
Now that he has it all running and in-place Doug has another trick up his sleeve: remote data collection. The Zaurus has a wi-fi card popped in the top (the blue thing) which can hook into any standard wireless network. Doug’s plan is that whenever his EV is within range of a wireless network he’ll have the software “push” data to a website.
Presumably when it’s parked at home or the office he can be providing a live web page that shows graphs with the state of the batteries, voltage levels, costs, etc.. all while they are charging or just sitting there relaxing after a hard morning’s drive to work.
Great job Doug and thanks for sharing! Be sure to check out Doug’s EV website and his Blog. Here’s the blog entry with all of the details and schematics for this rig (plus a clever way to get a cheap 5v regulator). Doug is even being good enough to share the source code for anyone who wishes to follow in his footsteps.