Conex Club Magazine - no.3 - 2003

Conex Club Magazine - no.3 - 2003 - Voice recording and playback mode (IDM1400)

Reading time: 6 minute

The main topics presented

1. Electronic components for SMT (IV) technology

Integrated active components

The evolution in the field of capsules of integrated active components has been very fast. Figure 1 (from the article) shows this evolution.

The rapid evolution of capsules was a consequence of the demand for components with as many terminals as possible having dimensions as small as possible. If in the 1970s the standard DIP (Dual In-line Package) capsule dominated the integrated circuit family, currently used circuits in capsules type BGA, TAB, CSP, all being compatible with surface mounting technology.

Figure 2 (from the article) shows different families of capsules of SMD active components. Higher performance ceramic capsules are expensive and are used especially in the military.

The most common capsules in applications where there are no special tightness requirements are the plastic ones.

Daca cracks may occur in the case of ceramic capsules due to the differences between the coefficients of expansion of the substrate and of the capsule, in the case of plastic capsules the cracks appear mainly due to the humidity accumulated inside.

Another feature of plastic capsules is the limited range of working temperatures (0 -70C). The most used plastic capsules are those of SOIC integrated circuits with seagull wing-shaped terminals ("gull wing") and "J" shaped, followed by PLCC capsules and "fine pitch" PQFP components.

Small Outline Integrated Circuits (SOIC) Capsule

"Small Outline Integrated Circuit" capsule - SOIC or short SO is derived from the DIP capsule by reducing the distance between the terminals to 50 mil compared to 100 mil.

The capsule is used for chips larger than those that can be housed by SOT capsules for transistors. The SO terminals are arranged on two sides of the capsule body, being formed in what is called the gull wing or term "gull wing" which will be preferred.

This capsule has its origins in the 1960s, being used in the Swiss watch industry. In the electronics industry, the company Philips is credited with introducing this capsule in 1971.

Small Outline Capsule "J" (SOJ)

Small Outline J (SOJ) capsules were originally designed for memory circuits for convenient contact of address and data lines between multiple circuits placed in the vicinity.

SOJ capsules have "J" terminals like PLCCs but have pins placed on only two sides. The SOJ capsule is a variant that combines the handling advantages of the PLCC capsule with the route routing advantages offered by the SOIC capsule.

The standard pitch is 50 mils but there are also variants of 33 mils (0.8 mm). The possible widths of the body are 300, 350, 400 and 500 mils, the most widespread being those of 300 and 400 mils.

Thin Small Outline Package (TSOP)

The Thin Small Outline Package - TSOP capsule is widely used today, especially in memory circuits. It is a capsule with two rows of "gull wing" terminals.

TSOP capsule has a very low height (1.27 mm) which makes it preferable in portable equipment and PCMCIA cards.

The capsule is made with four distances between the terminals: 0.3, 0.4, 0.5 and 0.65 mm. The TSOP capsule allows the efficient encapsulation of a large semiconductor chip, as is the case with memory chips.

2. Switching power supplies - MC34063 integrated circuit

The switching power supplies presented in this article are made using the linear integrated circuit MC34063 which is a DC / DC converter.

It is produced in a capsule SOP-8 for assemblies made in SMT technology - or in the DIP-8 capsule. The location of the terminals in the DIP-8 configuration is shown in figure 1c (from the article).

This integrated circuit contains an internal oscillator whose frequency varies within limits 100Hz… 100KHz, depending on the size of the load. It is provided with internal protection in case of accidental short circuit at the outlet or exceeding the maximum allowable temperature of the capsule (70C).

The assemblies executed with this integrated circuit are relatively simple, do not require "special" components and are easy to make practically.

The sources are distinguished by a high efficiency, better than 80% and offer a stable voltage at the output, with a variation in relation to the load up to 0.1%.

Five variants of switching power supplies were made and tested in their own laboratories, using the linear integrated circuit. MC340063AP1. Two of them are voltage boosters, two voltage boosters, and one provides negative voltage.

3. Voice recording and playback mode (IDM1400)

Editing allows high quality recording and playback of short voice messages (maximum 20 seconds), using a minimum of electronic components.

It can be used in signaling systems for voice warnings, warnings, as well as in various games or electronic montages.

Examples are: apartment bells with voice messages, where the message changes when the owner leaves the apartment, car warning systems for fastening seat belts when starting on the spot, warning systems related to perimeter sensors, warning systems warning for public spaces: schools, museums, places of entertainment, etc.

The presented recording-playback mini-system benefits from an EEPROM memory that can store the recorded messages for a period of 100 years. The maximum recording time is 20 seconds. 5 different messages can be recorded, lasting 4 seconds each.

Both the microphone and the low power speaker are included. Optionally, a rotary switch can be included to select the message to be played.

Can be set two modes of operation: scrolling the entire message when a push-button is pressed and scrolling the message continuously until the push-button is released.

4. Pony Prog - AVR microcontroller programmer

Derived from the famous 8051 family from INTEL, the microcontrollers from the AVR series produced by the American company ATMEL, are made in an architecture RISC (Reduced Instructions Set Computer), and are a serious competitor to Microchip's well-known PIC microcontrollers, both in terms of hardware and software facilities and lower price.

Regarding the input-output and data handling functions at the level of the functional blocks, The AVR family architecture is based on 32 general purpose registers, present in all types of microcontrollers, which are directly connected to the Arithmetic-Logic Unit (ALU).

The number of instructions differs depending on the type of microcontroller, from 89 to 118 (the average instruction at the PIC series is only 35).

It is noteworthy that the working speed in the case of the RISC architecture has been significantly increased compared to the CISC architecture, the vast majority of the instructions of the AVR series being made in a car cycle, so in a single clock period.

The programmer presented is an adapter that works together with the Pony Prog program and the serial interface presented in issue 11/2002 of Conex Club magazine. The connection between the two modules is made simple, through a 10-pin "pin-head" connector at 90 degrees.

Four different types of sockets were used (4, 20, 28 and 40 pins), so that all types of microcontrollers from the AVR series can be programmed. A 4 MHz quartz oscillator was also configured on the printed wiring. Capacitors with a value of 100nF have the role of disconnecting the supply voltage.

The jumper JP1 selects the Reset signal, RST. The other position of this jumper makes it possible to program the microcontrollers in the series C51, AT89S8252 and AT89S8253 in the base for microcontrollers AVR AT90S4414 / AT90S8515.

5. MAX 038 - Function generator

The MAX038 monolithic integrated circuit is a function generator that synthesizes with great accuracy and with very few external components various waveforms: triangular, sawtooth, sinusoidal, rectangular and impulse.

The output frequency can be controlled over a wide range (0.1Hz… 20MHz) by means of a 2.5V internal voltage source (REF) with forbidden band (high stability), a resistor and a capacitor.

The filling factor can be modified by applying a control signal in the +/- 2.3V range, thus facilitating the modulation of pulses in duration and the generation of sawtooth waveforms. In the same way a frequency modulated signal can be obtained. The filling factor and frequency can be adjusted independently.

6. 433MHz MA receiver

The presented receiver offers a diverse area of ​​applicability from which we can list: the interface for the remote control receiver modules for remote operation of the gate opening mechanism, electrically operated doors with motors, exterior or interior lighting, alarm systems.

The maximum operating distance is 50m compared to the remote control transmitter.

The repeater works on the base frequency 433MHz, a remote control with one or two channels can be used as a transmitter. The 433MHz receiver module works with amplitude modulation (MA) of rectangular pulse trains (emitted by the remote control).

Functionally, the receiver has two blocks:

  • the radio frequency block built around the T1 type transistor BF199;
  • the amplifier and signal-forming block made with the operational amplifiers U1A and U1B type LM358 (both in a DIP8 capsule).

7. Laboratory source 5-40V / 4A

It is briefly presented how to make a source in laboratory switching with integrated circuit L296 (P), which allows to obtain a variation of the voltage on the load between 5 and 40V at a maximum current of 4A.

The L296 (P) circuit has thermal protection and short circuit on load. The basic configuration of the source is of the voltage lowers type - Buck.

If L296P is used the R5 resistor is important! It allows the limitation of the short circuit current, to 4A, in the present diagram. Otherwise, the limitation is made to 7A. L296 does not have this possibility of current limitation.

The maximum input voltage is 50V. Attention is paid to the choice and calculation of the power transformer.

The output voltage is adjusted from P1. It is recommended to mount insulated on a heat radiator and use a cooling fan - a small Sunon model - mounted on the radiator.

8. TFDS 4500 (2.7 V to 5.5 V Serial Infrared Transceiver Module Family (SIR, 115.2 kbit / s)

Transceivers TDFU4100, TFDS4500 and TFDT4500 are a family in modular construction with low consumption, compatible with the standard IrDA 1.2 for infrared serial data communications SIR, which supports transfer speeds up to 115.2kbit / s.

In a transceiver module are placed a PIN photodiode, an infrared LED emitter - IRED and an integrated circuit, IC, low consumption for control.

Transceivers manufactured by Telefunken are available in three types of capsules, including "Baby Face", the smallest SIR transceiver on the market (until 2003).

9. TOIM 4232 (SIR Endec for IrDA Applications Integrated Interface Circuit)

The TOIM 4232 circuit is a specialized component, intended for interfacing the 4000 series of infrared transceivers with the RS232 serial interface.

The circuit has an internal oscillator, which uses a quartz crystal with a frequency of 3,6864 MHz. The baud rate can be programmed between 1200 and 115200 bits / sec. Power consumption is below 10mW normally operating and only a few mW in standby.


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