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-1

I make my own enclosures after trying to find a match for my products. I have a small production, cut the sheet metal to size, punch holes with a small hand punch, make the keypad then coat it with layers of Lacquer and then assemble the electronics that go along with the enclosure. Here's a sample link... I don't know if they allow links here, but my site ...


3

Drive the transformer from a low impedance. The source impedance and the transformer's primary inductance form an R-L high pass filter which determines the LF rolloff of the circuit. So with the attenuator ahead of the transformer it'll be all about the treble ... no bass.


2

That circuit is rather simplistic and a bad idea. It's clear enough how it's intended to work, but the implementation is lacking. In particular, the lack of emitter resistors in the output stage is downright irresponsible. I was going to go into detail on how this circuit works and how to tweak it, but now realize you didn't provide component designators. ...


1

In the Australian world, we use AS 1102 Graphical Symbols for Electrotechnical Documentation, which is derived from IEC 60617 Graphical Symbols for Diagrams. The following areas are covered in the database: Conductors and connecting devices Basic passive components Semiconductors and electron tubes Production and conversion of electrical ...


0

You should look at The Cog, the video commercial of Honda, for some ideas. Aside from the fan and the windshield wipers, there is also a section there where speakers are turned on, and the vibration from the sound causes mechanical movement. Edit: Russell McMahon gives a lot of interesting ideas in the comments to the original question. My main ...


2

BLM likely refers to Murata BLM series of chip ferrites. See www.murata.com . You might just select the ferrite part to reduce noise at the frequency that you believe would disrupt your circuit. Just be sure that the DC resistance is not so high that it could give a significant voltage drop. The Murata spec sheet should list these parts by recommended ...


0

I'm going to suggest that you start by visiting the many websites that cater to hobbyists. These include: seeed studio, adafruit, parallax, pololu, sparkfun There are a ton of other sites that supply these sensors and also provide guidance on how to best make use of them.


0

Can you weight it? If there are not too many pieces you could look at transmission at some IR wavelength. (We use to stack up paper for IR attenuation in grad school.)


1

Since you are not trying to determine the absolute height of the stack, but rather to detect a change, I'd suggest not measuring thickness at all. Nominal thickness of 20 lb paper is .004 inches. You could use essentially a microscope with a video camera, and adjust the height to provide maximum maximum contrast in the image. This is basically how cameras ...


0

Typical paper is pretty thin (a few thousandths of an inch or less). Using thicker paper would make the problem easier, but assuming you can't do that.. You could use an LVDT with a spring on the core to provide downward pressure and a puck at the other end with an air nozzle or porous surface supplied with compressed air to prevent the puck from touching ...


1

You need to create some logical functions here. This can be done with switches of various types, but not the way you've shown it. You want the lights to come on if the door is open OR SW4 is closed. You want the buzzer to activate if the door is open AND SW4 is closed. This requires SW4 to have two poles: simulate this circuit – Schematic ...


-1

You don't need the resistors, you need a new SW\$2\$, and this should work: SW\$2\$ is a double-pole single-throw normally closed switch, and when the door opens and SW\$2\$B closes, the buzzer will sound unconditionally.


5

If you want a reliable power-up reset, a simple RC is not the way to do it. The capacitor you suggest (plus a diode across R1 to discharge the capacitor when power is removed) will sort-of work most of the time, and some crappy products actually use something like that. Instead it would be better to use a supervisory circuit such as an ADM803 (open drain ...


1

These days, a microcontroller is almost always the answer. You can buy an STM32F4 Discovery board for around USD$15 depending on the source. The Discovery has a built-in STLINKv2 JTAG/SWD programmer. The STM32F407 MCU that it mounts (an ARM Cortex-M4 that runs at up to 168MHz) could generate a wolf howl with a DMA-driven DAC while spending most of its ...


6

Get an ISD1610 voice recorder chip: - If you can get a wolf sound thru your PC speakers, you can record it onto this device and it will playback whatever is recorded. It isn't hifi of course. digikey_link.


2

No, your "charge pump" circuit doesn't make any sense and won't work. If you look at the equivalent circuit in the datasheet (figure 51 on page 21), and then read the functional description on page 8, you'll see that it's much more complicated than that. The charge pump monitors the output of the input comparator, and on every transition, it charges or ...


10

It depends on quantity and your ability/desire to pay for additional steps in the manufacturing process. The only extra step that is typical in BGA assembly is X-Ray in QA to ensure that reflow occurred under the part as it cannot be visually inspected. You can choose whether you want this step or not. If you don't X-Ray and the assembly house has poor ...


0

The next variable always covers the half section that you add when you mirror the table.


1

I know you asked this a while ago, but in case you still need the answer, yes it is possible. According to http://www.cburch.com/logisim/docs/2.1.0/guide/menu/edit.html "Note: Logisim's clipboard is maintained separately from the clipboard for the overall system; as a result, cut/copy/paste will not work across different applications, even including other ...


0

From the data sheet the highest voltage on a GPIO is 3.8V. So If I have 5 Volts going through a.... lets say 1M resistor to the 3.3V input pin is this ok? The datasheet DOES explicitly cover the situation by stating an absolute maximum voltage. Above that voltage damage MAY occur. If the IC is operating mis-operation may occur. Or may not. ...



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