OBD request frequency

autopi-dongle
#1

Hi All,

Ultimate Goal: To increase the obd sampling rate of the AutoPi.
Intermediate Waypoint: find out how the sampling rate is controlled.

Hi all,

The AutoPi requests signals from the OBD at a frequency below 1 Hz when connected to the car’s OBD. When I connect the laptop with CAN Hacker to the car, I see that the car’s OBD can easily handle higher frequencies. When connecting the AutoPi to a OBD emulator (CAM Spi click chip), it is clear that the AutoPi limits the request rate.

I expect that this sampling rate is limited in the autopi-core code, with a parameter set in one of the .sls files. But I cannot find out where and how.

Anyone got a clue of a hint? Which file is the MAIN confuration file (.sls?) that the minion reads in order to start the process?

Many thanks in advance!

#2

Hi @mehere,

Have you seen this post?

Its hidden under the advanced settings. The AutoPi should be able to do around 200Hz, but a some point both the ECU and the Raspberry Pi Zero becomes the limit. It should be able to go faster on a RPi3.

(I’ll see if I can make an official guide for this)

best
Peter

#3

Hi Peter,

Thanks for the quick reply! I didn’t read that threat, but there was already a readout_0 sec. If I select custom, and change the interval to 0.1s, I don’t see a change. Should this work? Or am I missing the point?

many thanks,

#4

If you’re looking at data on dashboard, you won’t see it that fast. I believe getting data via API should work though.
I was driving around today and data that should arrive every 5 seconds, didn’t arrive so fast. Maybe the fault’s on my side.

#5

Thank you for your reply.

I check the speed by SSHing into the AutoPi, and monitor the Redis database using ‘redis-cli minitor’. Here I don’t see a change in the frequency…

Can I use this to make a digital gauge cluster?
#6

Hi

Make sure that the loggers that you configured is properly synced to the device, you can do so by making sure that the device is using the most recent version of the core (see software updates page on my.autopi.io), and then clicking sync above the loggers.

FYI: If you update the device via the software updates page, it will also include the currently configured loggers, so in that case it’s unnecessary to also click sync.

Best regards
/Malte

#7

How can we achieve this from custom code ? ( Same question as in Best way to do scans ,,, really ). I see 1 to 2 Hz only.