Radioshack Special - Build your own bot ears!

robodude666 · August 21, 2006, 6:42am

Hmmm, Took a look at your parts list. You know it will be a lot cheaper to get everything from jameco or digikey? Radioshack sells resistors for like 5 for $1. Jameco sells a bag of 100 resistors for $1.

I am going to be needing to buy an IC from Digi-Key sometime soon. Could someone make a parts list for this project with Digi-Key product numbers? I tried searching for resistors at Digi-Key but I found some messed up prices.

Also, what is J1?

sn96 · August 21, 2006, 8:18am

J1 is a 3pin header. You don’t need this if you use a perf board. Also, even though Jameco or digi-key are cheaper, why buy 100 resistors when you only need a few?

It’s to much work to try to make up a Digi-key parts list for these parts. Radioshack is more convienent.

robodude666 · August 21, 2006, 8:39am

Well, you can always use the extra resistors for later projects or if you mess it up youl have extras to retry it. One thing I learned in life is get extra parts just in case, especially if they are tiny.

I guess I will be ordering the components from Jameco and the ICs from Digi-Key.

zoomkat · August 21, 2006, 9:06am

Be advsed that many RS stores are no longer carryng electronic components. RS did carry a resistor assortment for ~$4 that would be handy if you plan on doing any amount of electronic tinkering. In the past I’ve ordered from BGmicro below. They have a smaller selection of stuff, but you don’t get as lost finding things as one might at the bigger suppliers. You can download their catalog in pdf format for easier brousing for parts. Do note that at one time digikey charged an extra $5 for orders under $25.

bgmicro.com
bgmicro.com/catalog.asp

sn96 · August 21, 2006, 9:49am

It’s true that many Radioshack stores only nave a limited selection of components, and some stores are notorious for not keep up with the inventory; parts in the wrong bins, etc.

They do have an online website to order all of the parts I have provided with the RS item numbers.

radioshack.com/category/inde … cp=2032058

I’m not trying to push getting the parts at radioshack, it’s just a bit easier to get all of the components from one location since I already did the search work. All the item numbers I have in the parts list will work and available from radioshack.

If you want to get your parts from a different provider, go for it. I was just trying to make it as simple as possible by listing the item numbers so one would not have to go searching.

sn96 · August 21, 2006, 9:57am

NickReiser:

I’m not sure if this would work for quick sounds, since there might be too much delay between the two readings to grab both sound values at the “same” time.
In that case, the second-read sound would probably always seem a bit less loud than it should, but perhaps you’ve got something in your circuit to prevent this.

Assuming that the values can be grabbed quickly enough not to matter, this psuedo code should work to determine the relative positions:
// Get the two ADC readings.
RightMic = GetADCch1()
LeftMic = GetADCch2()

//Find the ratio of one ear to the other.
Ratio = RightMic / LeftMic

//Assume a servo mid position pulse length of 1500
//Assume that 2250 is 90 degrees to right
//Assume that 750 is 90 degrees to left.
//If that's true, then adding 750 to mid position = full 90 degrees right.
//And subtracting 750 from mid position = full 90 degrees right.

//Is the ratio more towards the right mic?
If Ratio > 1 Then
//Then find where to move to.
NewPosition = 1500 + Ratio * 750

//Is the ratio more towards the left mic?
NewPosition = 1500 - Ratio * 750

//Move the servo to the new position.
MoveServo(NewPosition)
There’s more direct ways to accomplish the above, but I thought it best to space everything out into simple steps.

The first new placement might not be very accurate, but after a few loops of this code, it should hone in on the target pretty well.
There needs to be a delay between reiterating, though, to allow the servos to move and then quiet down again.
So, like a human ear, it would easily track down a long drawn out sound, but wouldn’t be terribly accurate for pinpointing quick, unrepeated sounds.

That’s fantastic Nick, I some how missed this post. I like the idea. I have an extra sound sensor board (older proto type) I can mail you if your interested. You can experimant with it if you want. It would need to be assembled using the parts list I provided though. Or, I could just give you one I assembled.

It’s this board:

img457.imageshack.us/img457/2664/abtop5fg.th.jpg

The only problem with this board is the silk screen for the microcontroler wires. The CLK and CS are reversed. You would need to wire CLK as CS and CS as CLK

nickreiser · August 21, 2006, 1:21pm

A free sensor board?
Well, if you insist.

I’ll give ya a PM.

chunga · August 21, 2006, 1:27pm

lucky ducky

italian_guy299 · August 21, 2006, 2:27pm

awwwww…puppy dog face

robodude666 · August 24, 2006, 7:39am

Hey guys,

I was bored so I made a parts list of everything thats needed (at least what I saw was needed). It is broken down into 4 sections and it goes by this format:
Quantityx Type (Parts in the diagram)] (comments)]
Where ] means optional

Enjoy. I was able to find everything at digikey but the mics. Mics are $4 each at radioshack. If you have one near by then just stop by. No need to pay shipping for 2 mics lol.

Resistors
5x 1k (R1, R2, R5, R8, R9)
2x 2.2k (R6)
1x 10k (R7)
2x 1M (R3, R4)

Caps
2x .047uF (C1, C2) (Ceramic Caps)
2x 10uF (C3, C4) (Polarized Electrolytic Caps)

ICs
2x LM741CN (U1, U2)
1x ADC0832 (U3)

Diodes
2x 1N4004 (D1, D2)

Misc
2x Electret Microphone Element
2x 8-pin IC Socket (Wide I believe)
1x Three pin header (Male? Optional if you make a jumper to your micro, or solder directly to pins)

Total: Under ~$20

Feel free to correct me.

sn96 · August 24, 2006, 8:54am

You can get any type of electret mics, Digi-key has them as well as Jameco.

robodude666 · August 24, 2006, 11:08am

The mics I found at DigiKey looked totally nothing like the ones you were using so I thought that they were wrong. My bad.

At digikey when it says “standard package” of 100, that means 1x buys you a lot of 100 parts?

sn96 · August 24, 2006, 12:39pm

yeah, standard package of 100 means 100 pieces.

For example, you might want to buy 100 SMT resistors that will come in cut tape. Tape - meaning a strip of thick paper, almost like cardboard that looks like movie film. This strip has pockets for the components covered in peel-able cellophane. Normally, manufacturing companies order by the 1,000s and the come on reels that look like movie reels that a machine uses to feed the parts and place on the board.

The reels

http://www.reel.biz/images/reels-galore.jpg

Close up view of a plastic tape type:

http://keaco-smt.com/keaco.3.jpg

robodude666 · August 24, 2006, 12:48pm

Yea, I seen the paper stuff before. But that is weird thougt that standard pack of 100 means you buy 100 of them when you buy 1 quantity.

digikey.com/scripts/DkSearch … 13&Site=US
for example is a standard pack of 200 1.0K OHM 1/4W 5% CARBON FILM resistors… Minimum to buy is 5 of them so that means you buy 1,000 resistors for only 27cents? Is this possible? Or can I just not count right?

chunga · August 24, 2006, 1:33pm

not sure wat your saying robodude, but 1000 resitors of that would cost you 8.55

saipan59 · August 24, 2006, 1:35pm

No, I think the “standard package” means how Digi-Key gets them from the manufacturer.
The 27 cents would get you 5 resistors.

Pete

robodude666 · August 24, 2006, 1:43pm

But that goes against what mike said. If a standard package is 200 that means buying 1x quanity of resistors will buy you 200 resistors. If you buy a quanity of 5 then your buying 1000 resistors. Since they say 5 costs .27 that means you buy 1000 resistors for .27? Doesn’t it? Or am I going crazy?

saipan59 · August 24, 2006, 2:44pm

Trust me on this - 27 cents gets you 5 resistors. See my previous post.

Note that the description of the item does NOT say “package of 200”.

Pete

sn96 · August 25, 2006, 6:48am

Opps, did I make a mistake?

I’ll check on this when I get home from work.

Sorry if I’m wrong on this.

EDIT Ok I just read RD’s comment. The standard package is how it comes from the manufacture but they sell (out of that box) in qtys of 1, 10s etc… They mention “standard package” so if you wanted all 200 pieces, you would get the whole box.

Just what Pete said.

I was carless answering this in the beginning.

italian_guy299 · August 25, 2006, 2:15pm

thx for clearing that up. Ive been following this thread but never posted. sorry. But that makes sense now.