Skip to main content ↑ ↓

Messages

This section allows you to view all Messages made by this member. Note that you can only see Messages made in areas you currently have access to.

Messages - Catmacey

2
Project development, ideas, and suggestions / Re: Dirty LCD
As a bit of a followup;

The LCD Break-out Eagle files are on Github in case you want to use them as a starting point for something else.

I created this board for use as the display on my mini drum machine.  I was using the classic Nokia 5110 84x48px LCD which you can find everywhere but moved to the 1202 because it was really cheap and gives you more pixels (96x68px) to play with.  I made the break-out as a drop in replacement for the Spark fun Nokia 5110 break-out hence the unconnected pin 5.

If you are interested in seeing the display running (in the drum machine) there is a demo on youtube.

The source and Eagle files for the drum machine are also available on Github including and includes code for getting the LCD up and running if that's useful for you.

Enjoy.

Catmacey
4
Project logs / Re: Digital audio effects processor (Guitar stomp box)
Just a quick update to this project log.
After a lot of tidying up I've released version 1 of the C++(Chipkit/Arduino) code for this project up on GitHub.
You can also find the Eagle Schematics and PCB Layout up there too.

As it stand the device has the following effects;
Flanger
Tremolo
Pitch Shifter
Delay/Echo
Bitcrusher

Any or all of which can be active at the same time.

https://github.com/Catmacey/ChipStomp/
5
Project logs / Re: Digital audio effects processor (Guitar stomp box)
I eventually found some time to start assembling my Chipstomp.  The PCB is perfect, the only problem being a mistake I made in laying out the PIC's ICSP clock line which I managed to have connected to completely the wrong pin...

That was easily fixed with a small bodge wire, but I'm defintely sure now that the black solder mask is not a good idea for an early prototype.  It's just too hard to spot the tracks underneath, even with a bright light shining from the other side.

Here's a photo of where I am so far with the build. 


I've got the digital side of things up and running after a bit of messing around with the Chipkit bootloader and Microchip's free compiler limitations.  The crux of the problem being that
my buttons are pulled high - pulled low by the putton press - whereas the Chipkit DP32 is the other way round.  This mean't the the bootloader was always being activated on reset.  The fix was to change a single value in the bootloader board config file and rebuild the project.  The hassle is that the bootloader project needs to be compiled with -s optimisation and mips16. These options are not available in the free xc32 compiler, so after a bit of messing around I settled on the simplest solution which was to use the 60 day free trial of the pro version.

If you interested, my intention is to publish the full circuit and source code so as a starting point my Eagle CAD project files are available on Github. As I find more time I'll be tidying up, revising and publishing the rest.
6
Project logs / Re: Digital audio effects processor (Guitar stomp box)
I just got the boards back from DirtyPCBs today and they look very nice. 

On a couple of boards I quickly checked the silk is sharp and clean, no blotches.

The black solder mask is very cool but I might choose a different colour for a first prototype next time as makes it very hard to spot the traces underneath, that's good for a final version but might actually be a hinderance in a prototype where I typically have to make alterations...
 
Here's a quick photo from my phone.

I'll take a better picture with my camera when I get them home. I'm hoping that I'll have a chance to start building one up this weekend.

Here's a link to a hi-rez photo (1.4Mb) if you're interested.
7
Project logs / Re: Digital audio effects processor (Guitar stomp box)
Updates:
1. I changed the title of this thread to include "(Guitar stomp box)" as I realised it sounded a bit grand and misleading as it was.

2. Just received notification that the boards are back from the fab.  Excellent. 
I must say I'm really liking the Dirty PCB experience so far, especially the notifications.
8
Project logs / Digital audio effects processor (Guitar stomp box)

Here's another "Guitar stomp box" project...

This one combines a Chipkit DP32 (PIC32MX) with an Open music labs Stomp Shield to sample audio, mess with it and squirt it back out at 44Khz. 

It uses the built-in 10bit ADC for input and two 8bit PWM DACs to provide a 16bit output.  It's a clever solution to use two "small" high speed PWMs mixed like that, thank you Open Music Labs.

So far I've have Delay, Bit-crush, Tremolo and Flanger running. All of which can be run at the same time with headroom for more.

I've written more here http://http://catmacey.wordpress.com/2014/04/30/introducing-the-chipstomp/ and will be publishing all code and schematics once I have it all tidied up - yeah they all say that don't they...

The PCBs are done and are currently with Dirty PCB.
10
General discussion / Re: Cost-effective European parts suppliers for small quanti
Thanks for the replies.

It's annoying isn't it to read about people in the US making tiny spurious orders from DigiKey and the like. I'm always thinking "Yeah great for you, that's 20EUR in shipping alone for me..."

But on the plus side and as an update. I've just found that RS offers free delivery to courier depot locations within big cities.
Lucky for me Barcelona has a couple of these that are fairly close to me.  Unfortunatly the don't stock exactly what I want, but at least that's an option I didn't know I had.
11
General discussion / Cost-effective European parts suppliers for small quanties
Hi,

I'm trying to find a comprehensive supplier for small quantities of electronics components who will deliver to Europe (Spain) without crazy shipping and handling costs.

I've been using a combination of Ebay, Aliexpress and other smaller suppliers such as;
Lawicel : http://www.lawicel-shop.se
Watterott : http://www.watterott.com
NKC : http://store.nkcelectronics.com
Stellatech : http://stellatech.com

All of whom are great for what they have, and have reasonable prices for both the parts and the delivery.
What they don't have is an extensive range which means you have to take what you can get rather than being able to find a specific part.

I keep coming back to the likes of Mouser, Farnell, Digikey etc.
They have a fantastic range of parts of course, but unless you're spending 100's of euros the cost of shipping and handling seems to far outweigh the cost of the actual components.

For example; I really like the look of some Bourns rotary encoders with built in RGB LED. I'd like to grab 5 to play around with.
The code is : BOURNS - PEL12T-4226F-S1024

Element 14 has them for 5,57EUR each + TAX + 18EUR Handling + 9 EUR Shipping.
That's 64.48EUR in total... Crazy.

Digikey has them for 5.57EUR each + TAX + 18EUR Shipping.
= 55.48EUR

Mouser has them for 4,33 each + TAX + 20EUR Shipping which is better but still nearly double the cost of the parts.

Obviously all these big guys are not really interested in selling tiny quantities of bits and bobs to the likes of me. I understand that but it's really frustrating when you have a particular part in mind that isn't available in the more hobby-friendly places.

So. My question is what do you guys do when trying to get your hands on small quantities of specific part?

Do you use the big guys and save up a big order of parts to offset the cost of S+H or do you have other secret places?

Cheers.
Matt
12
General discussion / Re: Hello all UK Hacker/Maker
Hi. I'm kind of a UK member. At least I would have been 12 years ago having lived in the Portsmouth/Southampton area for 20 years. Now I'm in Spain (Barcelona) so I'm not sure if I still qualify... :o)
It's really great to hear about hackerspaces in the UK, I only wish they existed when I was there. 
We have a few here in Barcelona too now - even had a mini-maker fair last year!
14
General discussion / Re: shipping PCB's internationally from USA
My trick is to pick up a box of cheap Christmas or birthday cards from a charity shop.
I sellotape the PCBs into the middle of the cards and send them though normal mail in the envelopes provided.  I've not sent as many as Matseng but I must have sent a good three dozen that way from here in Spain to all over with no problems.
The card provides good protection against the PCB tearing through the envelope and my guess is that they so obviously look like a greeting card of some kind that the postoffice is a bit more lenient.

An extra plus is if you happen to be sending them at around Christmas or on someones birthday the recipient gets a double surprise!
15
Project logs / Re: PlingPlong - A portable synth
That's a really nice project.
How do you find the time to keep coming up with things like this?
I've been working on my drum-machine for nearly two years now...

( ! ) Fatal error: Uncaught exception 'Elk_Exception' with message 'Please try again. If you come back to this error screen, report the error to an administrator.' in /var/www/dangerousprototypes/forum/sources/database/Db-mysql.class.php on line 696
( ! ) Elk_Exception: Please try again. If you come back to this error screen, report the error to an administrator. in /var/www/dangerousprototypes/forum/sources/database/Db-mysql.class.php on line 696
Call Stack
#TimeMemoryFunctionLocation
10.01572445992session_write_close ( )...(null):0
20.01602577616ElkArte\sources\subs\SessionHandler\DatabaseHandler->write( )...(null):0
30.01602578392Database_MySQL->query( ).../DatabaseHandler.php:119
40.06412717152Database_MySQL->error( ).../Db-mysql.class.php:273