A while ago we started an EV club at school. I had always been interested in electric cars and built a few cars and bikes of my own. I even rebuilt a few EZGO electric golf carts. One was such a monster I used it to tow a dead car out of my way.
During one meeting I was asked how hard it would be to create a charging station that would use our existing campus ID cards. That was Thursday. By that weekend I had already threw together the necessary pieces. I always shop at surplus houses and buy parts just because…
I had bought some credit card insert type readers that were listed as being used in Gas pumps. It just seemed fitting to take a gas pump reader and put it in an EV station.
I had a really rough proof of concept working on an old dell P3 before long. since my primary job was the campus card system, interfacing to that was a breeze.
I refined it a bit and brought it to school the next week for a little show and tell. Before long everybody wanted to see it and try it out. It was even put out at green week for students to try their cards in it.
Since my main goal was low price I was happy to try integrating a raspberry Pi. I was surprised to see how much faster it was than the HP and Wyse thin clients I was using before. The SD card memory was a great improvement over the Compact Flash I had been using.
There has been interest in using proximity type cards at school so I extended the software to accept both swipe and prox cards using a Weigand style reader. that reader seems to be the most expensive part in the system right now.
All inbound communications are over SSH/SCP and it will send emails out when the charge completes. There are some fancy status apps. Originally I was asked to set it up to charge $1 but right now it only validates the card as an active community member. The billing code was written in C using our card systems interface developer kit. I would like to replace this with the paypal API and make it suitable for public use
having the additonal processing power has led to the idea of using that hdmi port for some advertising. Just a free running slideshow or movie that plays in the background as the charger does its thing. the movie can be updated over ssh as needed and will be the next iteration. I will still keep the VFD display but will integrate that into a daughter card using the Pi’s internal serial pins. that save me the need for the max232 chip on the interface card.
This Pi seems to be big enough to share.