SU1436274A1 - Touchless switch - Google Patents

Abstract

The invention relates to a pulse technique, namely to contactless electronic switches, which are triggered when touching the touch pads, and can be used in control panels for different devices, in particular switches and input devices in a computer. The purpose of the invention is to increase the reliability of the operation of devices. The touch switch contains the first delay device, D-flip-flop 2, the second delay device 3, one-shot 4, n touch pads 5, multiplexer 6, bit block 7, electronic key 8, counter 9, output register 10, digital-analog converter 1, clocking 12 and output 13 tires. Improving the reliability of operation is achieved through the introduction of a digital-to-analog converter 1I, an electronic key 8, a second device 3 of the oscillation device and a single vibrator 4. 2 Il. (L

Description

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one

The invention relates to a pulse technique, namely to contactless electronic switches, which are triggered by touching the touch pads, and can be used in control panels for various devices, in particular in switches and information input devices in computers.

The purpose of the invention is to increase the reliability of the device.

FIG. I is a functional diagram of a touch switch; in fig. 2 - diagrams for his work.

The touch switch contains the first device. delays, D-flip ger 2, second device 3 delays, one-shot 4, n touch sensor (adok 5, multiplexer 6, block 7 bits, electronic key 8, counter 9,. output register 10, digital-to-analog converter 11, clocking 12 and weekend tires 13 -

The second input of the first.-Device I dropper is connected to the output of the digital-to-analog converter 1I, the first input-to the clock bus 12, and you -. move to the D-input of the D-flip-flop 2, the C-input of which is connected to the output of multiplexer 6, the S-input to the output of the single-oscillator 4, the non-inverse output to the input of the second device 3 delays, and the inverse output to the second input of the electronic key 8, the first input of which is connected to the clock bus 12, and the output to the input of a block 7 of a discharge; 5 n outputs of which are connected to the corresponding touch pads 5 and n information inputs of a multiplexer 6, the control inputs of which are connected to the corresponding counter codes 9, digital-analogue inputs transform tel 11 and information. inputs profitable register 10, the outputs of which are connected to the information bus 13,

- input - with the output of the one-shot 4, the output of the second device 3 delay sub-,

It is connected to the input of the one-shot 4, and the output of the electronic key 8 is connected to the input of the counter 9.

The operation of the touch switch is built on a cyclical basis. The cycle consists of n cycles. The duration of the cycle T is equal to the period of the following clock pulses received on the clock bus 12. In each

with to

15

20 25

30 0

35

five

The tact is polled by one touch pad 5, and the scan of all pad 5 takes place during a cycle.

When generating control signals, clock pulses with a period T are received via the clock band to the multiplexer B input, through the bit 7 block to its information inputs, via the electronic key 8 to the C input of the counter 9. A sequential change in the states of the counter 9 outputs leads to alternate polling of the information inputs of the multiplexer 6 connected to the corresponding touch pads 5. All touch pads 5 of the switch are interrogated. The parallel code from the outputs of the counter 9 also goes to the information inputs of the OUTPUT register 10 and the information inputs of the digital-to-analog converter at the output of which a voltage is generated corresponding to the code on its information inputs. This voltage controls the delay time of the first I delay device.

When you touch the i-th touch area-. 5, the capacity of the operator’s body is added to its mounting capacity and the charging time is increased.

The output r-1 pulses of the main device G of the delay and multiplexer 6 (while the operator’s finger touches the platform) are shifted in time by the value L 0 (FIG. 2d), which causes the D-flip-flop 2 to transition to a new state (FIG. 2e): at output Q, the state of logical 1, at Q, logical O.

About arrives at the input of the electronic key 8, prohibits the passage of 9 clock pulses to the counter, therefore the code corresponding to the number of the pad that the operator’s finger touches is recorded at the inputs of the counter;

Delay conditions, which increase the noise immunity of the switch, do not allow it to respond to a random signal, and after 0.25 s (the delay time is selected), starts the one-shot 4, producing a single pulse-strobe, which blocks O-trigger 2 at input S and enters to the C input of the output register, permitting its operation.

So. as the mounting capacity of the touch pads can be different, the values of a and also can be different, which can make the switch insensitive to the touch of the operator’s finger. To avoid this drawback, a digital-to-analog converter 11 is introduced into the switch circuit, which makes the delay time of the first delay device a function of the polling number- touch pad, so the values of jf, and l are chosen optimal when setting the switch.

Connected to the information inputs of the multiplexer 6, the block 7 bits serves to discharge the capacitances of the touch pad 5.

Claims (1)

Invention Formula A touch switch containing a counter, an output register, p sensor pads, clocking and output information buses, a D-flip-flop, a discharge unit, an input of the discharge unit is connected to the input bus, and the outputs are connected to the corresponding touch pads and information inputs multiplexer, first delay device, multiplexer, n information which inputs are connected to the corresponding sensor pads, the control inputs are connected to the counter outputs and information inputs of the output register, whose outputs are connected to the information output buses, and the multiplexer output is connected to the C input of the D flip-flop,, characterized in that, in order to increase the reliability of its operation, a digital-to-analog converter, an electronic key, a second device for holder and one-shot, the output of which is connected to the C input of the output register and to the S input of the D flip-flop, the direct output of which is connected to the input of the second delay device, the output of which is connected to the input of the single-oscillator, the first input of the first delay device is connected to the input bus, the second input to the output of the digital-to-analog converter, and the output to the D input of the D-flip-flop, the inverse output of which is connected to the second input of the electronic key, the first input which is connected to the input bus, and the output to the C-input of the counter, the outputs of which are connected to the inputs of the digital-to-analog converter.