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bromagosa / Snap4Arduino

Binding Snap! and Arduino together
http://snap4arduino.rocks
GNU Affero General Public License v3.0
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Improve timer accuracy #204

Closed seteahconnoc closed 7 years ago

seteahconnoc commented 7 years ago

I am using Snap4Arduino to measure the dark time of a forked light barrier. Obviously, the timer continuously counts upwards by tenths of seconds. Is there a method to achieve higher accuracy? In the source code of "Snap!" itself, I was able to get the appropriate result by changing the function "getTimer" in "objects.js". Sadly, I do not succeed in reaching this with "Snap4Arduino". Any suggestions would be great.

I got the idea to use the pulseIn function from "jguille2"'s SA5, but didn't succeed by now.

jguille2 commented 7 years ago

Hi @seteahconnoc , Two different problems here: 1- Snap! timer accuracy and 2- Latency with board communication

1 Snap! timer accuracy

Snap! timer accuracy has an easy solution. You said you hacked getTimer function in objects.js. Snap4Arduino is an Snap! Then, the solution is the same... but certainly you must build the app (it is a node app... and you can't change directly js sources)

But Snap! is great! And you don't need to hack anything! Because you have JS functions available into Snap! blocks!!! For example, you can do: timerinmillis or you can delete the Math.floor rounding...

2 Board latency

But if you need a high timer accuracy and you are reading board sensors... maybe the latency with the board communication will not allow this wanted resolution. If this is the case, you can use pulseIn Arduino function with SA5 firmata (then the time is measured by the board). And if your measurement is more complex, the only way will be another firmata modification.

Ok, I think this is all. You can close both issues... And if you have problems with pulseIn, we can continue in https://github.com/jguille2/SA5/issues/4.

Joan

seteahconnoc commented 7 years ago

This sound quite plausible. I guess, it 's just the small technicalities that are getting in the way. So, I am very thankful for your help.