Using a raspberry pi and a hall effects sensor to capture shaft rpm. this code will give me the rpm. but after a run i need to start over with zero rpm. this couter just keepd adding the rpm every test run My function code counter = flow.get("counter") || 0 counter ++ flow.set("counter, counte…

How are you going to calculate the revolutions per minute?

i will not be running the engine for a minute, so i need a math function Angular velocity (rad/sec)

Once again I misunderstood. I thought you were once again confused between the count value and rpm. If you feed the input sensor (after the Switch node) into a function containing this it will tell you the rpm by measuring the time between pulses. let lastTime = context.get("lastTime") || 0 const…

now where talkin. my reading is 3000.98765421456 How would i eliminate everything after the .98765421456

[image] dirtydredrt: How would i eliminate everything after the .98765421456 Start by reading the help pane for the gauge node. In particular: " The msg.payload is searched for a numeric value and is formatted in accordance with the defined Value Format , which can then be formatted using A…

[{"id":"c502d54b.368d98","type":"tab","label":"Flow 2","disabled":false,"info":""},{"id":"8583a880.175fd8","type":"inject","z":"c502d54b.368d98","name":"Sensor","props":[{"p":"payload"},{"p":"topic","vt":"str"}],"repeat":"","crontab":"","once":false,"onceDelay":0.1,"topic":"","payload":"1","payloadT…

You don't need a function node. Just configure the Text nodes to send the topic as Strings highThreshold and lowThreshold [image] And please change the labels, the thresholds are not revs per minute values, they are total revolutions. You have this at the moment. [image]

Thanks Colin you are a super star. one more issue. From the dashboard, start run button is not clearing the counter. inject CLEAR COUNTER is msg.topic = reset I need to run this command from the start run button

That is exactly the same issue as the thresholds isn't it? Set the topic in the button and send it to the revs function.

Small engine dyno need help to reset my counter after run

General

dirtydredrt 30 March 2021 15:45 59

got it.
I'm all most done. one more issue.
I have a start run button that will reset my gauges and ready the run
my problem is i added two text boxes one to input the lowThreshold number and the other to set highThreshold. I have added a function between text box and count revs function my code is incorrect

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Small engine dyno need help to reset my counter after run

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