Need a short beep circuit

The Lightning Stalker said:

This sounds like the perfect job for a PIC10

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I'd also try some low chips from freescale.

PIC10, 12, 16, 18, 30F, etc. all would work in the OP's app in some fashion. As would many AVR devices. The BASIC Stamp would work as well. I have worked, at one time or another, with all of the above. I mentioned the Arduino because the OP said it was once a consideration. If one excludes PWM generated tones as a consideration almost any uC with enough IO will work.

The considerations that remain do not involve the technical "nuts-and-bolts" issues but, rather, have more to do with the OP's comfort level with the software and development tools. I suspect that working at the assembly language level would be difficult. As would working with Cxx and MPLAB or similar IDEs because of the learning curve.

Enter Arduino and BASIC Stamp. Both have entry level development tools which allow one to work with a high level language. There are others too, e.g. Rabbit, that might work but I am not familiar with these.

The decision matrix is large.

Many years ago, while working on products that used a combo of a uC and FPGAs, I used a seat-of-the-pants paradigm that started with the concept:"the complexity of a solution is a constant".

While certain operations had to remain in the realm of the uC or FPGA others could be implemented in either. Therefore, whether the complexity is moved into FPGA code vs. uC code the complexity remained a constant. As does develpoment effort. (For the OP's app, we can add discrete circuitry vs. uC vs. PLD/FPGA vs. .... to the matrix.)

The decision becomes one of resources, e.g. people, skills, cost, time, etc., not "nuts-and-bolts".

A "short beep circuit" is not that simple is it?

Regards. JVJ

Here is my proposal.

I'll post the amplifier circuit later.

I considered 2 options:-
1. a variant on what I posted some time ago - the one you have already built & tested.

2. the one attached which uses an extra IC (the 4017 that you already have)

I chose number 2 since it requires a few less discrete parts & the sequencing is done with the 4017 rather than with RC timers.

Here is the Audio Amp suggestion.

It is a modified version of Figure 10 (page 4) of the National Semiconductor application note AN-69.

You only need Rc & Cc for high speaker currents. (I assume you won't want the sound to be too loud)

I suggest that you put a 100 uF and a 100 nF bypass capacitors from pin 14 to Gnd.

The 3.3 nF cap will attenuate the high frequencies in the square wave signal and should make it more mellow. See AN-69 Fig 10 if you want to adjust the tone. They have a pot in series with the 3.3 nF. The effect of that pot can be seen in Fig 11.

In order to complete the story, I've extracted the sensor interface circuit from the circuit I posted some days ago and added a note. See attachment.

Thank you very much! I'll get started on assembling that tomorrow after I pick up a couple resistors and capacitors for it. I'll let you know how I make out with it.

Kolero said:

Thank you very much! I'll get started on assembling that tomorrow after I pick up a couple resistors and capacitors for it. I'll let you know how I make out with it.

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You're welcome.

i thing this will help you



---------- Post added at 14:21 ---------- Previous post was at 14:18 ----------

Ref: Post #88 and my post #80. The collector of the transistor would connect to pin 4 of the 555. When ON the transistor would prevent the 555 from oscillating.

I would suggest that what ever oscillator circuit you use to generate a tone that the output duty cycle is as close to 50/50 as possible. An asymmetrical waveform may not be pleasing to hear because of the harmonics.

Regards. jvj

@ljcox: Regarding the tone oscillator in the latest drawing, you wrote "Set tone 1 with Rb c3, Tone 2 with (Ra+Rb)C3" Just for clarification, the two tones I want are G# and E (for High and Low, respectively). Using the resistor values I posted for the notes in Post #24, that would be G#: 15 K and E: 18 K. The C value I used is 0.1 uF.

Would I use a 15K for Rb and 3K for Ra in this case?

Kolero said:

@ljcox: Regarding the tone oscillator in the latest drawing, you wrote "Set tone 1 with Rb c3, Tone 2 with (Ra+Rb)C3" Just for clarification, the two tones I want are G# and E (for High and Low, respectively). Using the resistor values I posted for the notes in Post #24, that would be G#: 15 K and E: 18 K. The C value I used is 0.1 uF.

Would I use a 15K for Rb and 3K for Ra in this case?

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Yes. (I missed the point earlier)

If you want to learn more about logic design, you may in this thread helpful.