robtillaart:
HW sounds OK.If the baudrate influences the RPM it might be that the wires influence each other.
You could check if you have the same problems if you take IRQ1 (pin 3)================
What is strange is that the numbers are much higher than you expect [about 5000]. Is this correct?
Do you have a datasheet of the reed switch used?
What is its upper switch frequency?
First thank you for all the replies as a newbie I really appreciate this forum.
Glad the HW ok
Re baud rate I changed to IRQ1 (pin 3), this work fine on 9600 but on 115200 the readings are all over the place??
Re reed switch I cant find data sheet but what I have done is change the switch for another and this is the result and is no more than 1% different to the electronic tacho.
rpm37
rpm4363
rpm4332
rpm4363
rpm4347
rpm4347
rpm4580 ^^^^^^^^ Here
rpm4332
rpm4363
rpm4332
rpm4363
rpm4363
rpm4562 ^^^^^^^^^ Here
rpm4347
rpm4347
rpm4347
rpm4363
rpm4347
rpm4347
rpm4562 ^^^^^^^^^^ Here
rpm4347
rpm4347
rpm4580 ^^^^^^^^^^^ Here
rpm4347
rpm4347
rpm4347
rpm4347
rpm4347
rpm4363
Just the few disparities marked. Also tried at lower speeds and slightly higher, the results were as good.