Hello Electrified Miata Fans! The BMS logging code is installed and working! WhooHooo. I'm also a little sad because this means the go-karts usefulness to me will be coming to an end. I'll need to migrate all the Miata parts to the Miata! That said, the go-kart as been a very fun testing vehicle.
Of course, there are always some challenges. I decided to use the date and time to determine the names for the BMS logs. This way, at a glance, we can locate a file of interest and simply know the time period when activity happened. That sounds good, but where do the the Pi's get their time from? What happens when the power is shut off? The Pi's get their date and time information from the internet. If the Pi's don't have an internet connection, then they 'resume' operation from the last known date and time. This means if the Pi's have be shutoff for several days, their date and time will be wrong.
One reasonably cheap solution, involves using a Real Time Clock (RTC) module and installing this on one of the Pi's. The RTC module has its own 'coin' battery so isn't bothered by the power being shut-off. The other Pi's would need to know which Pi has the RTC and get their time from that Pi. So many little details that I get to learn!
Speaking of details, Joe is starting to port the BMS code to a processor we can actually obtain again. This involves a wealth of minute and unforgiving details as anyone who has played with microprocessors on the register level will attest too. This effort involves concentrated blocks of time, which are sometimes hard to find. Joe has promised me that we'll have a credible port in the testing phase by the 19 of March. From there, Joe will re-arrange the circuit board to include filtering capacitors, design for moving the connectors to the back of the board, and a few other details. After that, we'll submit the new revision to JLPCB and wait for 2 weeks to get the next set of boards. Once we've done this a few times, all the parts will be here to put everything in the Miata! We are getting close to putting this car together!
The formula-E-Mazda, our second project, made some good progress this
week as well This picture may look familiar.
Note that the 'transmission' is a trans-axle. We're performing the same exercise as we did with the Miata, mating the Leaf motor and trans-axle together. Broch got all
the measuring and marking done, so we knew where to drill the holes. Brian used the blue wrench (oxygen-acetylene torch)
to drill the larger access holes for the 2 Leaf motor blind holes. This was much faster than drilling with a 1 inch drill bit.
I've ordered parts for decoding the signal that comes from the Miata speed sensor in the transmission. Knowing the output shaft speed will allow me to RPM match the Leaf motor and shift without the clutch. I've also ordered a long drill bit that will allow me to drill through the plastic battery covers (and all the way though the battery holders). This will speed up assembly of the two remaining battery packs.
When the speed sensor is working, and the large battery pack is assembled the go-kart will be dis-assembled and all the Miata parts will migrate.
Next weeks tasks will be getting the large Miata battery prepared for assembly.
Also, we'll be completing the Motor Mount on the Formula-E-Mazda.
As always, thanks for reading! I look forward to hearing from y'all.
Bill likes cars that understand the 'go fast now' pedal