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Budget:

Small project <800

Posted on

5/16/18 2:54 PM

Buyer:

tec***

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Description

we need to modify an electronic in order to accept a new sensor .
the following text is just for reference contact us for more details:

I compared the characteristics of the sensor TGS4161, produced by Figaro and used on the board AELEBDSEN05, with those of the MG811 sensor, proposed as a substitute for the TGS4161, being the latter now out of production.

The main difference between the two sensors is the number and the mechanical arrangement of the pins: the TGS4161 sensor has 4 pins arranged on a circumference of 5.1mm diameter, while the MG811 sensor has 6 pins arranged on a circumference of 9.5mm diameter.

To insert the MG811 sensor on the AELEBDSEN05 board it is necessary to redesign the printed circuit board.

Then there are the electrical differences between the two sensors that involve a revision of the circuit.

The TGS4161 sensor is powered at 5V and requires a current of 50mA, with a total power of 250mW.

The MG811 sensor is instead powered at 6V and requires a current of 200mA, with a power of 1200mW, more than quadruple compared to the TGS4161.

The MC34063 switching regulator currently mounted on the AELEBDSEN05 board is able to supply the voltage and current required by the MG811 sensor, but it is necessary to recalculate the board feedback resistors R3, R4 and R5 and the capacitor C3.

Concerning the sensitivity to CO2 concentration, the two sensors behave differently.

The TGS4161 sensor has an output voltage that decreases by about 90mV when the CO2 concentration goes from 350ppm to 10000ppm, while the MG811 sensor voltage decreases by 60mV due to the same concentration variation.

This difference in sensitivity must be compensated by appropriately programming the PIC controller on the board.