3 ms·

Neat, what is your use-case for OBD-II data? I've been investigating ways to get data from a race car back to the pit crew via something like a raspberry pi.

jacquesm 9y ago
The microcontroller component of that is going to be a walk in the park compared to the radio component.
- NegativeLatency 9y ago
  Wifi with good antennas, or a cellular hotspot seems pretty easy.
  - jacquesm 9y ago
    Race engines are not known for their lack of EM emissions :) Vehicles are not friendly environments to begin with, race cars are outright hostile territory. Vibration & G forces, interference, fluctuating power, huge temperature variation, aerodynamic effects on antenna and cabling are all factors that will make this quite a bit of work to get to acceptable reliability levels. I like your idea of a cellular hotspot, that might be the easiest way to get to something that works. Compact, no external cabling. That's good. Edit: I tried running a webcam in a racecar in the mid 90's but it never got beyond the planning stage before the obstacles became insurmountable for the budget available, now, obviously a lot has happened in those years and F1 and other racing sports prove on a daily basis that the bandwidth is definitely there if you have the budget, you make me wonder how easy it would be to pull this off today, mostly likely you could just plug it together from some consumer components, a small tablet with a SIM card in a waterproof and vibration isolated enclosure would probably get you 90% there.
Nelkins 9y ago
Right now I just want to get more fine-grained data about my mileage. But maybe add some automation into the mix later on (remote start, etc.).
- gridspy 9y ago
  Ensure your remote-start doesn't turn into a remote-stop and a crash.
gridspy 9y ago
For the radio component - I suggest that you build a "block" of useful data and send that several times using very good Hamming (error correction) instead of error detection. If using wifi then consider UDP. You'll get better range out of something proprietary, I've had success in the 915 Mhz band. A spread-spectrum approach is better if possible. Ideal would be if the car assumes it cannot receive anything and attempts to send each block several times before beginning to transmit the next block. Another approach could be to send a window of blocks each time. Receiving outside the car is likely to be much easier - a large antenna can be used away from all interference. An option could be a human operator holding a directional antenna, visually tracking the car. You might also store the blocks within the car for later 100% accurate download.

jacquesm 9y ago

The microcontroller component of that is going to be a walk in the park compared to the radio component.

NegativeLatency 9y ago
Wifi with good antennas, or a cellular hotspot seems pretty easy.
- jacquesm 9y ago
  Race engines are not known for their lack of EM emissions :) Vehicles are not friendly environments to begin with, race cars are outright hostile territory. Vibration & G forces, interference, fluctuating power, huge temperature variation, aerodynamic effects on antenna and cabling are all factors that will make this quite a bit of work to get to acceptable reliability levels. I like your idea of a cellular hotspot, that might be the easiest way to get to something that works. Compact, no external cabling. That's good. Edit: I tried running a webcam in a racecar in the mid 90's but it never got beyond the planning stage before the obstacles became insurmountable for the budget available, now, obviously a lot has happened in those years and F1 and other racing sports prove on a daily basis that the bandwidth is definitely there if you have the budget, you make me wonder how easy it would be to pull this off today, mostly likely you could just plug it together from some consumer components, a small tablet with a SIM card in a waterproof and vibration isolated enclosure would probably get you 90% there.

Nelkins 9y ago

Right now I just want to get more fine-grained data about my mileage. But maybe add some automation into the mix later on (remote start, etc.).

gridspy 9y ago
Ensure your remote-start doesn't turn into a remote-stop and a crash.

gridspy 9y ago

For the radio component - I suggest that you build a "block" of useful data and send that several times using very good Hamming (error correction) instead of error detection. If using wifi then consider UDP. You'll get better range out of something proprietary, I've had success in the 915 Mhz band. A spread-spectrum approach is better if possible. Ideal would be if the car assumes it cannot receive anything and attempts to send each block several times before beginning to transmit the next block. Another approach could be to send a window of blocks each time. Receiving outside the car is likely to be much easier - a large antenna can be used away from all interference. An option could be a human operator holding a directional antenna, visually tracking the car. You might also store the blocks within the car for later 100% accurate download.