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Forum Index : Microcontroller and PC projects : Micromite Floating point HELP
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| helltek Newbie  Joined: 04/02/2015 Location: United StatesPosts: 29 |
Micromite Floating point HELP. I read voltage on analog pin setpin 23, ain print pin (23) 3.29871 I don't need so many digits since the last few change all the time. I need display just like simple 4-digit voltmeter 3.29V Can that be done? Is there some way to convert Floating point number? |
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| twofingers Guru  Joined: 02/06/2014 Location: GermanyPosts: 1138 |
Hi and welcome to the forum. just try the Str$ function please. Michael edit: MM Manual (p. 63) ? STR$(pin (23),0,2)&"V" Should work. |
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| helltek Newbie Joined: 04/02/2015 Location: United StatesPosts: 29 |
Can you provide example? The Str$(number) works when you provide the number. I have no clue how to make the string capture reading from analog pin. I did get all kinds of errors when I experimented the last few days trying to trunkate the reading. You can assign a=pin(23) but I could not assign it to string b$, etc. |
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| twofingers Guru Joined: 02/06/2014 Location: GermanyPosts: 1138 |
I changed my post. Please read again! |
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| helltek Newbie Joined: 04/02/2015 Location: United StatesPosts: 29 |
I tried it and did get the correct reading. THANK YOU!!! |
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palcal Guru Joined: 12/10/2011 Location: AustraliaPosts: 1805 |
If you want the voltage to stay as a variable instead of a string, you can multiply by 100 to get 329.871 then use the Int command so you only have the integer 329 then divide by 100 to get 3.29 Paul "It is better to be ignorant and ask a stupid question than to be plain Stupid and not ask at all" |
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disco4now Guru Joined: 18/12/2014 Location: AustraliaPosts: 844 |
Also see the CINT() function which returns the nearest integer. Gerry Latest F4 Latest H7 |
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| helltek Newbie Joined: 04/02/2015 Location: United StatesPosts: 29 |
Thanks Guys. I'll experiment see what works best. I was pretty good with GWBasic, BAT files, DOS, etc. I forgot all of it. |
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MicroBlocks Guru Joined: 12/05/2012 Location: ThailandPosts: 2209 |
With rounding the value solved, here is a good technique to use when reading analog values. There are very complicated and simple ones. :) I like the simple ones like a running average. Define an array and some variables [code] DIM Samples(10) Dim NumberOfSamples, Total, Average NumberOfSamples = 10 Total = 0 Average = 0 Index = 1 [/code] Fill the array with initial samples [code] for i = 1 to 10 samples(i) = pin(23) Total = Total + Samples(i) 'not use pin(23) because that would be a new sample! pause 10 next [/code] Then in your main code loop update the Voltage by calling a function: [code] Voltage = ReadVoltage() [/code] The function that will take a new sample and calculates the running average [code] FUNCTION ReadVoltage() Total = Total - Samples(index) Samples(Index) = pin(23) Total = Total + Samples(Index) 'Your new running average Average = Total / NumberOfSamples Index = Index + 1 If Index > NumberOfSamples then Index = 1 ReadVoltage = Average END FUNCTION [/code] Check this for syntax errors because i wrote this here without testing. :) This just keeps ten samples in an array and replaces the oldest one before calculating a new average. This smooths out readings so that spikes to don have a big effect. Good for when you are testing values on thresholds. A single weird reading will not set it off. The larger the array, the more samples, the more smoothing. All depends on what you need. Microblocks. Build with logic. |
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| helltek Newbie Joined: 04/02/2015 Location: United StatesPosts: 29 |
Thanks. I'll play some more. I'll try to average the readings and I will also need some calibration subroutine to run either at assembly time or maybe more often, but hopefully not. I need voltage divider to read voltage higher than the 3.3v on ADC pins. At high resistance let say 9k and 1k (divide by 10), even 1% resistors or better introduce large error. I may need one ADC pin fed by 3.3 volt and feed the voltage divider by the same 3.3 volt and write some subroutine to correct the error (make the reading match 3.3v as percentage of error and save the percentage to add or subtract from actual reading). Maybe there are easier or better ways. This is all that comes to mind right now. |
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