Digital Potentiometer DS1869 Converter TTL/RS232 MAX232   Tone detector NE567  

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Description : The DS1869 is an adjustable potentiometer integrated, can be adjusted in 64 lineal steps by means of push-buttons connected to the entrances of control or through its entrance of control for microcontrollers. The position is stored each time that this changes, in the EEPROM internal so that when be disconnected and the diet be connected again maintain finalizes it position before the desconexión.

Has the following values for the DS1869: 10K, 50K and 100 K

The tension of the 3 connections RH, RM and RL will not have but of 0,5 V above the tension of power supply.

Operation : The push-buttons of ascent and lowering they are controlled and filtered against repercussions and alone will be taken like a beating, the ones that be of duration over 1 mS. The successive delay between two beatings will be of 1 seg. If the push-button pressured is maintained an upper time al of I retard then the integrated circuit passes by way of car-repetition, in which the internal potentiometer displaces to 10 steps by second, with which for the traveled through total delayed some 7 seg.

The entrance "D" pin 3 does not have any type of I retard and acted al instant, to know the way about operation to see the datasheet.


Uses : This device can be useful for example to control through a microcontroller the sensibility of a specific sensor.




Converter TTL - RS232


Description : The MAX232 arranges internally of 4 converters of levels TTL al bus standard rs232 and otherwise, for communication series as them used in the computers and that now they are in disuse, the Com1 and Com2.

Operation :The integrated circuit carries internally 2 converters of level of TTL to rs232 and other 2 of rs232 to TTL with what on the whole we will be able to handle 4 signs of the port series of the PC, generally the but used they are; TX, RX, RTS, CTS, these two finalize you are them used for the protocol handshaking but is not indispensable their use. So that the max232 function correctly we owe to put some external condensers, all this we can see it in the following figure in which alone the lineas have been wired TX and RX that are the but usually used for almost any aplicacion.


Uses : This integrated is used to communicate a microcontroller or digital system with a PC or system based on the bus series rs232.




Tone detector NE567


Description : The NE567 is a detector of tone and frequency integrated and can also be used as generator of square sign. Through external components can be determined the central frequency of detection, the wide one of band of this, the delay of the sign at the outset among others.

Operation :The integrated NE567 activated its exit to level low when in its entrance be detected a sign of tone or equal frequency al configured in the NE567. To configure these parameters we will use the following formulae:

Central frequency of detection:

For a better thermal stability a value for R1 between 2K is advised and 20K just as indicates in the datasheet.


Wide of band:


Vi = Input voltage (  200mVRMS

C2 = Low-pass filter capacitor (µF)

The value of the capacitor C3 is not I criticize and normally it will be used formulates C3 = 2xC2. What does this condenser is to retard the sign or I press at the outset, to detect very short signs have that low its value but this will also do that be activated alone and be unstable.

Looking at the datasheet to see the characteristic curves of the integrated and information but detailed.


Uses : The NE567 can be used as detector of beacons for Infrared with what we will be able to locate a beacon that emit to determined frequency, can also be used for detection of ultrasounds.





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 Daniel C. Martin "ionitron" ··· Barcelona (Spain) ··· 2001-2006