looking for electronics help in Seattle area

The reason schools have school projects is so the kids can learn how to do projects. Paying someone else to do it is a serious dis-service to your kid. Leads to a society of people who know nothing more than how to pick up their iphone and call someone to do everything for them. You gotta encourage kids to take stuff apart even when there's no chance in hell they'll be able to put it back together.

This is a poor choice for a first project. You want your first few projects to be extremely simple and be easy to tell if it's working. This thing is a simple circuit, but it ties into a speak-N-spell that's totally unknown. You run the risk of a mis-connection or a short or static electricity busting the SNS and not have any idea what's broke. If you can't describe how a 555 works, you surely won't be able to diagnose a problem with a SNS.

If you had no choice in the project, you gotta move ahead. If it's a common class project, buy a pizza and host a work party for the kids. If you have a webcam and a microphone you can videoconference the kids together so they can share ideas. I like the freeware CQphone because it's very easy to use and has all the features you'll need in one simple program. Only hard part to using it is configuring your network router to forward the port to the right machine. And it's only good for two people. Most of the multi-way VC programs aren't free.

If you're stuck with the project... Learn how to solder. Take four resistors with full-length leads and solder them together to make a square. Take it apart and do it again...and again until you get proficient at getting the heat right. Then practice soldering three resistors to the same point. Learn that by offsetting the joints slightly, it's easier to make the third connection without melting the first joint. This improves your skill at getting the heat and time right.

If you can hook your garden hose between the faucet and the sprinkler, you can follow the picture you linked. Hook it up just the way it shows. Make sure the wires don't touch where they're not supposed to. When hanging parts in the air, it's helpful to have two sets of hands.

As for the explanation, the 555 is a tough one because it requires some basic understanding you don't have. After you learn a few basics, it becomes trivial. Reaching that "ahah moment" is the goal.

Google 555 data Download several datasheets. Some of the older original datasheets have better explanations of the basics. There are probably 10,000 web pages that explain exactly how a 555 works. Your problem will be sorting them out of the zillion hits you're gonna get. Most any basic electronics book you check out of the library will have some info on a 555.

It's also a somewhat lame project to take a Texas Instruments Speak and Spell, which is a rather clever device, and make it into a weak excuse for an effects pedal.

Consider a kit like this one:

You get a circuit board, so you just have to put in the components and solder.

John Nagle

It will not work too well; the LED is drawn in wrong!

Hmmm... I don't think ^^^^ I'm too *keen* on that, thankyouverymuch!

I'm not sure what help someone could give you in person -- short of teaching you/your son how to solder.

If you have *all* of the components (and the components came in

*that* kit), then you should be able to arrange them according to the "drawing" in the center left.

I.e., the "555" is a black, 8 legged device ("chip") about half an inch long and 3/8" wide (across the legs). There will be a half-moon shaped section missing in the top of the black plastic towards one end of the device (as shown in the drawing). This indicates which end of the device has pin 1 (since you've got to start counting from

*someplace*!). For example, the pin numbers on the device as shown in the drawing would be: 8 7 6 5 +----------+ | | ) | | | +----------+ 1 2 3 4

If you trace the "wires" in the drawing, you can see, for example, that pin 1 on the 555 has a wire running off to "B"; another wire connecting to one end of a 150 ohm resistor; and a third connection to the "-" side of a 10uF capacitor (the *other* side of the capacitor is shown as "+"!)

You can look at the *schematic* at the top left (above the drawing) and see the 555 dhown with pin 1 connected to "Ground" (looks like an arrowhead made up of three small lines getting shorter and shorter "pointing down"). This is labeled "B" in the schematic -- which corresponds with the "B" point in the earlier drawing. I.e., "B" is "ground" so anything shown with this funny arrowhead is the same point, electrically -- B.

With that in mind, the schematic shows the "-" side of a

10uF capacitor also connected to ground (B). And, one side of a 150 ohm resistor (squiggly line /\/\/\/ ). Again, these correspond to their counterparts in the previous drawing. [N.B. The "A" point in the drawing is the "power supply" for the circuit. Like B, anything in the schematic that is labeled as "A" represents the same point, electrically]

You should be able to *literally* arrange the components as shown in the drawing and connect them with lengths of wire as shown.

[The artist failed to show "wires" connected to all three pins of each of two of the larger potentiometers as is shown in the schematic :< Also, the LED is drawn backwards in the schematic -- it should look like a triangle pointing *down*. And, it should be connected to pin 3 on the 555 -- note that pin 5 has no connection made to it!]

The only components that you might have a little trouble with are the LED and the capacitors. The capacitors will have a black stripe along one side of the "can". This is the "-" side (if you examine the drawing, you will see that the capacitors *are* shown with this long black stripe!), The LED typically has one *flat* side near one of the two "legs". This indicates the "cathode" leg; the other leg is the "anode" (loosely speaking, cathode = "-", anode = "+"). The anode leg will also typically be *longer* than the cathode leg (though if the legs have been cut/trimmed, you can't rely on this indication, obviously!). You should be able to verify *both* indications: cathode is flat side and shorter leg.

The tricky part comes in trying to connect this assembly (once it is all wired together) to the Speak n Spell. The drawing at the right shows the insides of a speak n spell. You'll have to locate the points to which the A, B and C wires from your circuit tie in to the marked points on the speak n spell drawing.

Here, you'll need to be careful with the soldering iron not to end up shorting two adjacent pins (by putting too large a blob of solder *or* having the wire that you are affixing "accidentally" bridge two adjacent pins.

Be sure to remove the batteries from the Speak n Spell before tinkering with it! Set all the potentiometers to roughly their center positions to start off. Don't connect "C", intially...

Install the S'n'S's batteries.

The first sign of life should the LED flashing. The rate at which it flashes will vary with the setting of the "rate" potentiometer -- turning it one way will speed it up; the other, slow it down.

The S'n'S should continue to operate normally! All you have done, so far, is to steal power from it (via the A and B connections)

If the LED doesn't flash, you've connected something wrong. Remove batteries and double check all of your connections.

Once the LED flashes and you have verified that you can alter it's blink rate, you can remove batteries and connect "C" to the S'n'S.

With the batteries reconnected, you will find that the audio from the S'n'S will vary as you tweek the other potentiometers ("pots"). These adjust the extent that the "effect" alters the audio output.

Once things *seem* like they are working, set the rate potentiometer so the LED is flashing at a slow enough rate that you can listen *carefully* to the S'n'S and correlate how the sound is

*changing* when the LED is "on" vs. how the sound changes when the LED is *off*. You may have to experiment with different S'n'S sound selections to best hear the difference!

Be a "good dad" -- if he ends up frying the Speak n Spell, don't make a big deal out of it. Instead, challenge him to figure out what he did wrong -- what did he short out, etc. You should probably be able to undo any damage and still get it all working, again (though you may end up killing the batteries in the S'n'S while you are chasing down the problem -- so, have a fresh set available once you think you've fixed it!

(Half the fun of electronics is the "cursing" that accompanies your discovery of *YOUR* mistakes! :> )

No offense to your wife's cooking skills... :-/

HTH,

--don

Grrr... after all of that, I neglected to make clear:

The anode of the LED is the wide side of the triangular shape in the *schematic*. I.e.,

• |

** | *** | **** | *****| **** | *** | ** |

• |

the anode is on the left in this "illustration".

Note that the anode should be on the *top* in the schematic drawing -- connected directly to pin 3 of the 555 (this, coincidentally, places the anode at the top in the "drawing", as well) with the 150 ohm resistor connected to it's cathode!

If you get the LED installed backwards, it won't illuminate -- so, you'll think the circuit isn't working when, in fact, it may well be!

Apologies if I've taken anything else for granted. :<