# Do You Know Any Custom Circuit Builders Online?

#### ryevick

Joined Jan 17, 2012
8
I have a few ideas running around in my head and may want to pay someone to make them for me but I don't really know of anyone that offers small low budget project services online. Suggestion? Thanks.

#### MrChips

Joined Oct 2, 2009
23,858
This is good place to present your idea. What do you want built?

#### nerdegutta

Joined Dec 15, 2009
2,681

This is an international forum, if it's doable, we might be doing it together, but we need to know a bit more about those ideas in your head...

... and welcome!

#### jimkeith

Joined Oct 26, 2011
540
I can do it--used to make big bucks doing this, but those days are gone--now retired

#### ryevick

Joined Jan 17, 2012
8
I have a few ideas I sill want to think about before I do anything with them but they involve lights that would change colors in response to music being played... still brewing in my head... and I have to work out what I want more... but kinda putting a light show into a guitar body...

but another thing I want and I know this sounds shady but it's not meant to be. Is a pitch control for the mic on a headset with a 3/32 jack... I would need the signal split (mic and ear) so the mic could run through the pitch adjustments and then merged back into a 3/32 male jack with the headset.

#### ryevick

Joined Jan 17, 2012
8
well... that was a waste of time it seems...

#### Sparky49

Joined Jul 16, 2011
833
well... that was a waste of time it seems...
Woah - I hope you didn't mean that because no-one replied within 90 mins. Some of us have to eat and sleep you know...

On the subject of your design ideas... They certainly sound feasible, the coloured lights responding to sound has certainly been done before, if you Google "LED light organ schematic" you should find some easy circuits to play around with.

If you are still around then I'm sure these folks will be more than happy to help you further, I currently cannot do any small scale production.

Sparky

#### ryevick

Joined Jan 17, 2012
8
Woah - I hope you didn't mean that because no-one replied within 90 mins. Some of us have to eat and sleep you know...
Well no... the reason I said that was the second I posted the original thread everyone posted a response right away and when I quickly followed up they didn't seem to have anything else to say.. no offense meant to anyone of course but it seems the people here are more interested in larger scale projects. I would also seem to think that even if they were not interested in my tiny project, I could at least get some suggestions on where I could maybe go to get help for these... where are the small scale project forums? Where's the guy in his garage that wouldn't mind piecing something together for me one afternoon and not charging an arm and a leg to do it?

#### MrChips

Joined Oct 2, 2009
23,858
I would think the opposite. Many folks here are willing to chip in on small projects. The responsibility increases with the complexity of the project. I believe you will find some folks very much interested in your ideas. Of course, you have to come clean and state the complete project up front before anyone is going to commit.

With regards to forum response time, you have to remember that this is an international forum and there are members around the globe in different time zones. Secondly, for some of us, like myself, we are not on the computer all the time. Many hours may transpire before we get a chance to read the posts and respond again. You just have to learn to be patient with the responses. Sometimes it may take days before the same person is able to respond.

#### Papabravo

Joined Feb 24, 2006
16,459
We see this kind of query periodically. The people who make the original request are often surprised to find out what people think they are worth. The people who want to have things done, want things to be done at a cost too low to justify the effort. As a result, I think I can posit without fear of contradiction that, the number of time this has worked out is so close to zero as to not be worth mentioning.

If the mods or any member can present an example I'll be glad to retract that statement.

#### ryevick

Joined Jan 17, 2012
8
yeah i see your points... i suppose the smartest thing to do is to wait a few days and if i don't hear the responses i need to maybe check with some vo-tech schools and find suggestions for local guys

#### THE_RB

Joined Feb 11, 2008
5,438
...
but another thing I want and I know this sounds shady but it's not meant to be. Is a pitch control for the mic on a headset with a 3/32 jack... I would need the signal split (mic and ear) so the mic could run through the pitch adjustments and then merged back into a 3/32 male jack with the headset.
I'm not sure why it would be "shady" but I do know this one is not easy at all.

Real-time pitch changing of audio, even mono audio, is very difficult and requires some pretty involved digital signal processing. The audio is converted to digital, processed by a math algorithm in a DSP micro, then converted back to analogue again. It's probably a multi-chip solution involving some very skilled math and DSP programming. That's probably thousands of $$in design time IF you find someone cheap. The first "coloured lights" idea you had is a lot easier and only needs someone of hobby level skill to design. It might cost you as little as 500 or maybe less if you get a student etc to do it. Last edited: Thread Starter #### ryevick Joined Jan 17, 2012 8 I'm not sure why it would be "shady" but I do know this one is not easy at all. Real-time pitch changing of audio, even mono audio, is very difficult and requires some pretty involved digital signal processing. The audio is converted to digital, processed by a math algorithm in a DSP micro, then converted back to analogue again. It's probably a multi-chip solution involving some very skilled math and DSP programming. That's probably thousands of$$ in design time IF you find someone cheap.
Is there a way to use a normal microphone (battery powered) and run it through a pitch shift pedal such as the BOSS PS-5 (which I already own)... even though it is AC and then convert it back to a DC signal that could be merged as I mentioned?

#### t06afre

Joined May 11, 2009
5,934
It is some circuits doing pitch control MSM6322 and MSM6722 However do not expect top quality sound outputs from these circuits

#### Potato Pudding

Joined Jun 11, 2010
688
Digital is almost easier once you understand how it is done, especially if the code already exists. It seems you are talking about is digital spectrum analysis, math the frequency levels up or down, and resynth.

The problems are doing it fast, or accurately, or cheaply. (Pick 2 is a better plan.)

Digital filters require a time lag. For accuracy they should have a sample window of about 2.5 periods of the lowest frequency of interest. For 20 Hz you need a lot of sample time. 200 Hz not so much time. If you limit the range to above 2KHz then you won't notice the lag but the frequency response is going to be very noticeably arbitrary.

I probably have most of that wrong because it is not an area where I have studied much or had a chance to work yet.

#### THE_RB

Joined Feb 11, 2008
5,438
Is there a way to use a normal microphone (battery powered) and run it through a pitch shift pedal such as the BOSS PS-5 (which I already own)... even though it is AC and then convert it back to a DC signal that could be merged as I mentioned?
Yep the Boss effects pedal already has the clever DSP processor built in and will do the pitch shifting for you.

If you just want to change your voice to make it unrecognisable that does not require "proper" pitch shifting, just modulation. There are lots of cheap hobby kits you can buy like "cylon voice changer" or "dalek voice changer" etc, favorites of SciFi nerds.