Vehicle Data Logger / Video Recorder

[bpi]

Hi Everyone,

This is my first post here - quick intro - I run a company that specialises in retuning factory ECU's in performance vehicles. I'm a programmer day to day. I've done a lot of disassembly (SH4) on the Mitsubishi Evolution ECU. Not much hardware...

This post will probably have a lot of various questions posted over time as I seek to extend my hardware knowledge and experience. My software knowledge is pretty good and pays the bills, but the hardware side of things gets me excited.

I am in the early stages of designing a project to use in a race car that datalogs from the OBD port and various sensors, and records video/audio from a camera / microphone.

My first question is regarding storage of the sensor/OBD data (simple text) and video/audio data (not so simple binary)... I am not sure what is physically possible out of the below, but I see these as my initial options:

1. Flash (SD / MMC)
- my concerns are regarding write speed for video, and ability to interface with microcontroller

2. Hard Disk (notebook)
- concerns are vibration in race car, how to power (from device through vehicle 12v?)

3. USB Stick
- concerns are interfacing with microcontroller and write speeds for video.

If anyone has any suggestions or comments, I'd love to hear them. I'd like to keep this thread as a bit of a diary of the build of the project so that it may benefit everyone in some way.

Thanks very much,
Brendan

 

[Super_voip]

check the elektor site as they often have OBD projects and recently a discussion about OBD-3, as for the integration of video and data there are some small stand alone digital cam/corders which use SD. So long as a refernce signal was in the field of view it may just work

 

[bpi]

Thanks - I am actually involved in a couple of projects that do the OBD reading, so that side of things isn't an issue.

The main questions I have are things like:
* What hardware is involved in taking a video input signal, running through ADC, then streaming to file on SD/MMC.
* Is the write speed on SD fast enough to write streamed video? If not I need to look at hard drive storage solutions.
* What processor would be recommended for a project similar to this?

I'm not looking to have people tell me exactly how to build it, or to give me specs or circuits. I just need a high level overview of what parts and types of parts are required. I'm a pretty motivated person, I learn quickly, and I'm resourceful enough to find the sources of knowledge once I have a general idea of what's required.

Thanks,
Brendan

 

[Nigel Goodwin]

It's not just a question of digitising the video, you really need to compress it as well - or you won't get much data on an SD card. You can buy video cameras that record to memory cards, why not just buy one of those?.

 

[Iniciante]

Hellow every one! First sorry my English, because it´s bad... bpi try this comercial data logger https://www.picotech.com/data.html - I hoppe that it is usefull...

 

[bpi]

It's not just a question of digitising the video, you really need to compress it as well

Yep I know - that's where I think a software compression library for an MCU might come into play.

I've been doing a lot of research into various Microchip and Atmel processors. So far I'm no closer to deciding what processor would be suitable.

You can buy video cameras that record to memory cards, why not just buy one of those?.

Two problems with this:

1. Finding a camera small enough, especially considering that I want to be able to have multiple cameras (up to 4) placed at various points on the car, all recording onto the same device (4 different files).

2. I want to integrate the video into the datalogging internally, and not rely on externally having to download the movie from a video camera, synch it with the datalogging, and otherwise do any manual work.

I've been looking at MCU (libraries) that can write to HDD. I haven't found much in Microchip land, but saw some Atmel processors that have that functionality. At this stage I'm considering a HDD with vibration insulation as the video/audio storage mechanism.

Another question - say I work out myself how to get the video / audio mixed together, streaming through a processor, what kind of hardware or software products are available that will allow me to do (e.g. MPEG4) encoding?

 

[Torben]

Hi bpi,

Are you planning to build something like this?:

http://www.stackltd.com/synchronisedvideo.html?gclid=CNL-pMO6tY0CFRpohgodQ1G-tg

The data transfer speeds and storage restraints will probably be bound at least partially by the resolution and frame rate you want. What are your requirements as far as that goes?


Torben

 

[Super_voip]

I wouldn't start with a micro for realtime video compression, rather find a MPEG 4 encoder chip or chips for 4 channels. Brooktree have been making them for years. Of course you can just thumb your nose at all this and use a notebook(on batteries) a small USB hub(power by batteries),4 webcams ,a serial port for OBD, a 4gig Memory stick/card and have it running in a day.

 

[seveprim]

I would suggest bypassing both the Pics and AVR and go thr next level like the ARM range of processors they are much more suited to video compression also recommend using SD memory forget harddrive or use a USB flash memory stick could easily do it too with USB 2.0 transfer rates note ARM type processors usually support DMA high capcity rams and USB hosting ethernet support with mac built into hardware !

Atmel has a range of ARM chips but ARM is a generitc standard of opcodes I think there 11 or more chip makers that comply with the ARM codes !