sensor for detecting palay moisture

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oo nga eh...hindi ko alam ang number ng Greenwich ng Pampangga...mahal kasi ang Pizza Hut...hehehehehe

.....yon nga palang tester namin i dont if u believe is only using a 12 volt battery pack

[paranz]

oo nga eh...hindi ko alam ang number ng Greenwich ng Pampangga...mahal kasi ang Pizza Hut...hehehehehe

.....yon nga palang tester namin i dont if u believe is only using a 12 volt battery pack

moisture tester din ba? 

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okay naman yong capacitive but ilang volt ba ang dapat e charge with a cerctain density of palay.... parang ganon parin ang ang nakikita kung problem eh.... mahirap yatang e detect kung basta lang conductor plate ang ilagay don sa certain amount ng palay.....tama ba?

[Shey]

aahhh hhhmmm...we can test as high as tetra ohms using constant high voltage po....

ang problema mo yung stability ng contact points ng mga palay.. mas compacted sila mas mababa ang resistance.. kapag na-shake mo ng konti iiba na agad ang resistance..

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@ sir "paranz"

its an accurate insulator tester, for hi voltage equipment testing hehehehehe ang layo no???

[Shey]

okay naman yong capacitive but ilang volt ba ang dapat e charge with a cerctain density of palay.... parang ganon parin ang ang nakikita kung problem eh.... mahirap yatang e detect kung basta lang conductor plate ang ilagay don sa certain amount ng palay.....tama ba?

hindi naman DC ang ginagamit diyan.. it is an LC circuit kung saan i-dedetect mo yung frequency change kapag nag-change yung capacitance mo since Frequency is equal to 1 over 2PI times the square root of L and C ..

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oo nga... dapat dalawa ang constant at isang variable lang (moisture) para may accurate reading

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aaahhhh okay change in LC.....hey sir "******wired" ilang nano ba yon???

[Born2BeWired]

ang problema mo yung stability ng contact points ng mga palay.. mas compacted sila mas mababa ang resistance.. kapag na-shake mo ng konti iiba na agad ang resistance..

Same problem sa capacitive chamber. Pag nashake, mas tataas ang density, hence, magiiba ang reading.

Agree ako kay sir electron, mukhang mas mahirap kung resistance method. Yung moisture kasi may be concentrated deep inside the grain (sa palay). In that case, you wont get a meaningful ohmic reading.

[Born2BeWired]

aaahhhh okay change in LC.....hey sir "******wired" ilang nano ba yon???

He he, di ko na matandaan. Nung lumisan kasi ako duon sa dati kong trabaho iniwan ko lahat ang project files ko sa kanila, i did not keep a copy for myself.

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aaahhh okay.....using AC hi volt kasi kahit pa walang contact yong palay sa plate basta constant lang yong volume ng palay sa chamber parang ok pa rin....

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yong Ph ata nang moisture ang problem.....

[Born2BeWired]

aaahhh okay.....using AC hi volt kasi kahit pa walang contact yong palay sa plate basta constant lang yong volume ng palay sa chamber parang ok pa rin....

Kung AC test voltage mo, you are already measuring the reactance of the chamber, kaya it is essentially capacitive method na rin.

When we were designing the palay moisture meter, all available data at that time were based on moisture content vs frequency relationship, i.e. the measuring circuit will be a variable frequency oscillator with the capacitive test chamber (moisture content) acting as a frequency determining component.

Walang data available using constant frequency to measure the moisture content. As already mentioned, matagal ang pagmeasure ng moisture content using primary oven method. it will take weeks, maybe even months, to characterize palay at its full moisture range. This work is not appealing to me

[zer0w1ng]

This is interesting.
How about tests for humidity? For it should be proportional to water content.

Capacitive sensing is very viable but needs initial data for calibration.  This is tiresome to collect and maybe different for each variety of palay but I am not sure of this.  Few experimentation could prove this.

An idea is to have the capacitive box built with many parallel electrode fins and shorted to 2 alternate connections. The palay will be poured over it.  Should be also deep enough so that to have larger overall capacitance.

[Born2BeWired]

Capacitive sensing is very viable but needs initial data for calibration.  This is tiresome to collect and maybe different for each variety of palay but I am not sure of this.  Few experimentation could prove this.

Yes, in fact, AFAIK, this is the main motivation why NFA considered homegrown design.They had a number of imported and expensive palay moisture meter they would not use because of "poor accuracy". I never had the chance to examine these meters. Being these calibrated with palay of different variety is a plausible reason for this anomaly.

[marcelino]

capacitive sensor for moisture, interesting ha!
sir B, at what frequency po ba nag-operate yung 555 mo?
iba naman ang application ko... its soil moisture. i found a way of using a resistive sensor (sir electron and internet helped me about this), however, gusto ko din iconsider ang capacitive.

ano ba yung distance ng capacitive plates mo?