galvanic dissolved oxygen sensor

Hello

Hello

would you please help me for make dissolved oxygen sensor ?

i need circuit board.

i find any circuit board from this link :

https://wiki.dfrobot.com/Gravity__Analog_Dissolved_Oxygen_Sensor_SKU_SEN0237

in this circuit boar used TP5551 but i can not find this item .

1)i can not find TP5551 in my place then can i replacement by OP177GP or AD623AN or OP77GP or AD8572ARZ ? if i can do it then which of them is the best ?

2)If i can replacement TP5551 by another op-amp , is need change in circuit board or only i can replace without any change ?

3) if these op-amps ( OP177GP or AD623AN or OP77GP or AD8572ARZ ) are not the best choices please tell me your offer.

would you please send answers by numbers questions .

thanks

The circuit is low impedance, so any rail-to-rail op amp specified for 3V (or less) single ended operation should work.

The OP177G does not even come close, but the AD623 might work.

jremington: The circuit is low impedance, so any rail-to-rail op amp specified for 3V (or less) single ended operation should work.

The OP177G does not even come close, but the AD623 might work.

do you have circuit board for dissolved oxygen sensor ?

If i replacement TP5551 by AD623 , is need change in circuit board or only i can replace without any change ?

  1. No

  2. Do your homework: study the data sheets for the op amps.

The link at the bottom of that blog post says that the kit costs $169 and it's in stock now: https://www.dfrobot.com/product-1628.html

What is stopping you from purchasing that kit?

is circuit board of ph meter the same as circuit board dissolved oxygen sensor? can i use from circuit board of ph meter for circuit board of dissolved oxygen sensor ?

No. pH probes are completely different.

I suggest to buy the kit. It is clear that you have no idea what you are doing.

jremington:
No. pH probes are completely different.

I suggest to buy the kit. It is clear that you have no idea what you are doing.

i am mechanical engineering student also i must make mu own circuit board of dissolved oxygen sensor.

question 1-
why circuit board of pH probes are completely different compared with dissolved oxygen sensors? both of them send millivot and the circuit board must detect voltage. what are differents ?

ARAS820: i am mechanical engineering student also i must make mu own circuit board of dissolved oxygen sensor.

question 1- why circuit board of pH probes are completely different compared with dissolved oxygen sensors? both of them send millivot and the circuit board must detect voltage. what are differents ?

The difference would be the thing being tested for.

pH is not dissolved oxygen.

what are differents ?

The probe impedance is vastly different. Look it up.

ARAS820: i am mechanical engineering student also i must make mu own circuit board of dissolved oxygen sensor.

You must make your own board but your professors haven't given you the training required. I suggest you take one or two years of electrical engineering classes and then try again.

i am mechanical engineering student also i must make mu own circuit board of dissolved oxygen sensor.

Either you misunderstood the assignment, or your professors are unreasonable idiots. Take your pick.

how has program of dissolved oxygen sensor for calibration and compensate of temperature and salinity and pressure ?

DF Robot has code on their page that's doing temperature compensation. You'll have to do your own research on the other two.

They also have the complete circuit of their board posted; that should make it easy to reproduce. OpAmp should be a low noise one that's suited for high gain applications, the circuit uses a gain of almost 37x.

thanks all

wvmarle: DF Robot has code on their page that's doing temperature compensation. You'll have to do your own research on the other two.

They also have the complete circuit of their board posted; that should make it easy to reproduce. OpAmp should be a low noise one that's suited for high gain applications, the circuit uses a gain of almost 37x.

in DF Robot website used TP5551 i can not find , how can i replacement ?

How is copying a design without understanding it any different to buying one, for your professor?

An EE class on opamps (there are many online) may help you understand why that opamp was chosen and how to look for a substitute.

MorganS: How is copying a design without understanding it any different to buying one, for your professor?

An EE class on opamps (there are many online) may help you understand why that opamp was chosen and how to look for a substitute.

thanks