Up until the 1980s or so, a mechanic could check for shorts in a car’s electrical system by looking for sparks while removing the battery terminal with everything turned off in the car. That stopped being possible when cars started getting always-on devices, and as [Kerry Wong] learned, these phantom loads can leave one stranded with a dead battery at the airport after returning from a long trip.
[Kerry]’s solution is simple: a solar trickle charger. Such devices are readily available commercially, of course, and generally consist of a small photovoltaic array that sits on the dashboard and a plug for the lighter socket. But as [Kerry] points out in the video below, most newer model cars no longer have lighter sockets that are wired to work without the ignition being on. So he chose to connect his solar panel directly to the OBD-II port, the spec for which calls for an always-on, fused circuit connected directly to the positive terminal of the vehicle battery. He had to hack together an adapter for the panel’s lighter plug, the insides of which are more than a little scary, and for good measure, he added a Schottky diode to prevent battery discharge through the panel. Even the weak winter sun provides 150 mA or so of trickle charge, and [Kerry] can rest assured his ride will be ready at the end of his trip.
We used to seeing [Kerry] tear down test gear and analyze unusual devices, along with the odd post mortem on nearly catastrophic failures. We’re glad nothing burst into flames with this one.
Continue reading “Solar Panel Keeps Car Battery Topped Off Through OBD-II Port”
Automotive diagnostics have come a long way since the “idiot lights” of the 1980s. The current version of the on-board diagnostics (OBD) protocol provides real time data as well as fault diagnostics, thanks to the numerous sensors connected to the data network in the modern vehicle. While the hardware interface is fairly standardized now, manufacturers use one of several different standards to encode the data. [Alex Sidorenko] has built an open source OBD-II Adapter which provides a serial interface using the ELM327 command set and supports all OBD-II standards.
The hardware is built around the LPC1517 Cortex-M3 microprocessor and can accept a couple of different versions. Here’s the PDF schematic, and a set of Gerber files (ZIP archive) for the PCB layout, if you’d like to dig in to it’s internals. The MC33660 ISO K Line Serial Link Interface device is used to provide bi-directional half-duplex communication interface with the micro-controller. Also included is the TJF1051, a high-speed CAN transceiver that provides an interface between the micro controller and the physical two-wire CAN lines on the ODB-II connector. The serial output from the adapter board is connected to a computer using a serial to USB adapter.
The software is written in C++ for the LPCXpresso IDE – a GNU tool chain for ARM Cortex-M processors, but can also be compiled using a couple of other toolchains. He’s got instructions if you’d like to build the firmware from source, or if you’d like to program the adapter via Flash Magic.
We featured [Alex]’s inexpensive PIC based ODB-II interface way back in 2007, so he’s been working on this for a while and has a good grip on what he’s doing.
A lot of higher end cars are now coming out with RF fobs that unlock and start the car. There is no longer a physical key that is inserted in the ignition. It turns out that for BMW this means stealing the cars is extremely easy for a sophisticated criminal. We always liked the idea of metal keys that ALSO had a chip in them. The two-tiered security system makes sense to us, and would have prevent (or at least slowed down) the recent rash of BMW thefts that are going on in the UK.
So here’s the deal. A device like the one seen above can be attached to the On-Board Diagnostic (ODB) port of the vehicle. It can then be used to program a new keyfob. This of course is a necessary feature to replace a lost or broken device, but it seems the criminals have figured out how to do it themselves. Now the only hard part is getting inside the car without setting off the alarm. According to this article there are ultrasonic sensors inside which are designed to detect intrusion and immobilize the vehicle. But that’s somehow being circumvented.
You can check out a keyfob programming demo, as well as actual theft footage, after the break.
Continue reading “Keyless BMW Cars Prove To Be Very Easy To Steal”
Progressive Insurance announced that it will be rolling out its MyRate plan nationally. You participate by plugging a monitoring device into the ODB-II port on your vehicle. Once every six months you upload the collected data from every trip you’ve made. You’ll receive at least a 5% discount and maybe more based on your driving habits. In some states though, you could actually have your rates raised. Progressive will show you the direct impact your driving behavior has on your rate.
Continue reading “Progressive MyRate Hackable?”