Problem when read RPM from the tachometer socket of a CDI petrol engine about msrc

[dgatf]

I've increased the lower rpm range lately. Be sure you download the latest code

Which board for MSRC are you using?

[roscor61]

Hello,
I am using Arduino Nano 16Mhz / 5V for the final layout and an Arduino R3 for testing.
I'll download the new fw soon and I'll let you know ...
Thank you for the attention (xscuse me for the bad English)

[djatila666]

Hi, how do you Connect CDI to Arduino? Thanks El lun., 7 mar. 2022 19:05, roscor61 ***@***.***> escribió:

…

Hello, I am using Arduino Nano 16Mhz / 5V for the final layout and an Arduino R3 for testing. I'll download the new fw soon and I'll let you know ... Thank you for the attention (xscuse me for the bad English) — Reply to this email directly, view it on GitHub <#72 (comment)>, or unsubscribe <https://github.com/notifications/unsubscribe-auth/AUOOPLZFWNDDZNQF72RLYTLU6ZAPZANCNFSM5QD6HDRA> . Triage notifications on the go with GitHub Mobile for iOS <https://apps.apple.com/app/apple-store/id1477376905?ct=notification-email&mt=8&pt=524675> or Android <https://play.google.com/store/apps/details?id=com.github.android&referrer=utm_campaign%3Dnotification-email%26utm_medium%3Demail%26utm_source%3Dgithub>. You are receiving this because you are subscribed to this thread.Message ID: ***@***.***>

[roscor61]

I tried connecting the CDI tachometer plug output directly to both the D8 and GND pin to skip the optocoupler and use ERPM telemetry
I also tried using an optocoupler with 10k pullup or with BC547 as in figure, but the result is the same .. The OUT of the following schema go to port D8.
Below 250hz the telemetry go to 0 rpm. Above 250hz the measure is ok (BLADE=1, MULT=1)

I replicated the system with a low frequency generator with duty cycle at 5vpp and duty cycle at 35% as the tachometer signal. The result is the same.
With a generator msrc count without problem until 5 kHz signal and more.

[dgatf]

I believe 250Hz was the old code.

I've just tested with the latest code and arduino nano at 16MHz, can read as low as 60 rpm (1Hz)