Friday, February 29, 2008

Boards have arrived!

AVR ICSP breadboard adapters

Wednesday was board-day for me, as both my AVR ICSP breadboard adapter (ordered from BatchPCB) and my RGB button pad (ordered from Advanced Circuits) arrived. Much to my delight (and, to be honest, a little to my surprise), they both seem to work great. If you got in touch with me about the breadboard adapters, you'll be hearing from me soon; some are not spoken for, so if you'd like one, get in touch (jmg shift-2 upwardnotnorthward dot com). Expect a full post on the RGB pad once I've got it all up and running (right now I only have four RGB LEDs, so I'm waiting for more to arrive before I can fully build it).

Oh, and Advanced Circuits included a bag of microwave popcorn with my board order. Seriously.

RGB button pad custom PCB - unboxing photos


Wednesday, February 13, 2008

In the works: RGB monome-esque kit

Update: This kit probably isn't going to happen for various reasons. Read about it in this post.

After talking with Brian, and obtaining his blessing (and advice), I've decided to invest the money to produce a custom PCB for an RGB button pad prototype. This design is completely different than my original, offering improved colour-depth and brightness: the pre-prototyping I've done blows the old one out of the water. I hope to have the design completed and the custom PCBs in-hand by the end of the month. What I'd like to do is order a medium-sized run of these boards so that I can split the development cost with like-minded hardware hackers. These would not be "plug and play" kits by any stretch of the imagination: these would require significant extra work to get them to do anything, and comfort working with electronics. The numbers will be kept small, so we can all easily communicate, and hence people who want to participate will need to be in touch with me first. This will be nothing like the monome kits, which are much more user friendly! You have been warned! If you fit this description, I need your feedback, so please read on and respond!

There are a few ways I could do this that I'm considering, each with their own advantages and disadvantages (both for me and for you). This would only be a board with the buttons and LEDs on it, as well as the circuitry to drive the LEDs. No logic would be on-board, that would have to be handled by an external microcontroller, most likely an Arduino (although your favourite board could work, too).

What I'm most likely to make first is a 4x4 button pad design to work with Sparkfun's buttons. It would include a small overhang to hold the circuitry to drive the LEDs, which would interface serially with whichever microcontroller platform you'd like. The serial interface would only control the LEDs; the buttons' wiring would be broken out to control however you like. All of the inputs and outputs will be neatly bundled together in a ribbon cable. Code and schematics for running it off of an Arduino (and possibly other platforms) would be made freely available. It would be possible to daisy-chain multiple 4x4 boards, but this would require more complicated off-board wiring. This kit would be the least expensive option, and also offers the most flexibility. The disadvantage would be that it would require the most outside wiring to get working, especially if you're planning on chaining multiple boards.

What I'd really like to make, personally, is an 8x8 button pad on a single baord, which would include a full serial interface for both the buttons and the LEDs, as well as power circuitry on-board (an 8x8 RGB pad uses a lot of current!). It is highly doubtful that I would do this initially for several reasons: for starters, it would be a much more complicated board for me to design and test. Perhaps more importantly, it would require me to invest in the professional edition of Eagle, which is an additional $600. That's money I need to put up initially, and it's money that would have to be factored into the cost of the boards for any other developers. So, unless feedback is overwhelmingly in favour of the 8x8 pad, this would most likely come later, if the interest existed.

Finally, there's the logic board. For now (and probably forever), this would be an Arduino. If you want to hook it up to something else, then by all means you could do so; if I hook it up to something else, I'll probably post code for it. For now, though, I'm developing on an Arduino and maybe AVR, so that's what I'll offer.

In terms of functionality, it will probably be possible to make this "monome-compatible," like my monomuino project. Of course, the colour functionality would not be accesible in this mode, you would have to pick the colour you wanted to display. I can't stress enough: if you want to build a monome, buy the kits from monome! This is for people interested in hardware tinkering. This device could also be controlled with a to-be-developed custom protocol which supports full colour, but in terms of software to utilize this, it would have to be custom written. Hopefully, if we get together a group of about a dozen people to do this, we'll be able to put together some neat stuff.

Here's what I'd like to hear from you:
  • Which kit(s) would you be interested in? How many?
  • The LEDs I like are from, and are much more expensive than ones you can find on Ebay, but much higher quality. If I bought a bulk order of those, and sold them at around cost (that's the discounted bulk cost, not the individual LED cost at superbrightLEDs), would you buy them bundled with the kit? (This would add ~$20 to a 4x4 kit, and ~$80 to an 8x8).
  • Similarly, would you want the Sparkfun buttons bundled with the kit? This would save you shipping from Sparkfun.
  • Can I contact you in the future with questions about the kit, and/or with announcements about the kits' availability?
  • Any other questions or comments you might have
If you email me (at jmg -atsign- upwardnotnorthward -dot- com), I will not give your information out to anybody under any circumstances. I will contact you precisely once, to let you know that the boards are available, unless you explicitly give me permission to contact you more, or ask that I not contact you at all.

If you don't trust me with your email address, and never want to hear from me, then simply leave your thoughts in the comments below. That's cool, too.


Monday, February 11, 2008

AVR ICSP 6-pin breadboard adapter

AVR ICSP (6 pin) breadboard adapter

Update: the boards have arrived. If you're interested in getting one, please email me at jmg (shift-2) upwardnotnorthward (period) com.

I think I'm really starting to get the hang of EAGLE CAD; not only is it no longer frustrating, I now really enjoy designing boards in it.

I've been teaching myself about directly programming AVR chips (stay posted for an article on that), and since I'm too stubborn (and cheap) to pay for a development board, I built and have been using an Evil Mad Scientist Labs-style minimalist target board. It works great, but the problem is you more-or-less need a different board for every different type of chip you want to program, plus, you need to shuttle the chip back and forth from the breadboard to the programmer. It would be great to be able to program the chip in-breadboard, by the dual-row header pin won't allow that. You can run wires directly from your programmer to the breadboard, but that's a little messy. So, I decided to make a simple breadboard adapter for the ICSP header.

This has been done before, but I really don't like dealing with perfboard, and I was itching to try having a PCB manufactured, so I designed the adapter and ordered a bunch up from Sparkfun's BatchPCB service. My design is set up so that the Vcc and GND connect directly into the bus lines of the breadboard to save two wires later on. I ordered a bunch of extras, so if anyone out there is interested in one, drop me an email and we'll work something out (assuming they work properly when they arrive).


Tuesday, February 5, 2008

Announcing: Arduino serial communications class at The Hacktory!

I'm very pleased to announce that I will be teaching Advanced Physical Computing Experiments, a course about serial communications with Arduino, at The Hacktory in Philadelphia! The course is design as a natural follow-up to their highly successful introductory Arduino classes: whereas that class deals with how to set up the Arduino and use it to control simple components, this course will deal with controller more complicated, "smarter" components, as well as talking with other devices like computers.

I've mentioned before that one of the things that terrified me when I was starting out was the prospect of reading integrated circuit datasheets and figuring out how to interact with them. Now that I've gotten the hang of it, I'm amazed at the huge range of chips on the market, and how easy it is to interface with the vast majority of them once you know a few basics. It really has the potential to transform your projects, and I'm really excited about sharing this knowledge.

So what are you waiting for? Go sign up!


Monday, February 4, 2008

Brief updates: RGB monome-clone v0.2 status, learning Eagle, inspiration's lousy timing, etc.

A brief update for any subscribers I might have picked up:

As I mentioned in the original post, I've got a design in my head for a revised RGB button pad that will be much brighter and have a much wider range of colour. I'm going to need to design my own PCBs for it so I've been learning Eagle, because I can't get the open source KiCad running satisfactorily on OS X. It was tough at first, but Tod gave me some great advice that helped get my head in the right place:
One of the problems you'll encounter when first starting to use Eagle is that it may look like a GUI program, but you have to throw out anything people have learned about GUIs for the last 15 years.
I also found Tangent's tutorials to be incredibly helpful, more-so than any written tutorial I found (the rest of his site is pretty great, too). Now that I'm getting the hang of it I'm really starting to love Eagle and have essentially decided it's worth the investment. I'm going to do a bit more breadboard prototyping before I buy the full version and design the PCB, so if any open-source evangelists want to switch me over to a free solution, you've got about a week to convince me!

I ordered 100 cheap common anode RGB LEDs from Ebay today. I figure if they're as good as the ones from then I've saved a tonne of money, and if they're not I can always get the more expensive ones once I'm done prototyping. A couple hours after ordering them I came up with a revised design that uses fewer components, less power, has a much simpler PCB, and, of course, requires common cathode LEDs. Just my luck. Still, I'm not positive which design will work better, so I'll probably just get some common cathodes as well and develop them both in parallel. Expect the first Rev. 2 write-up in the next week or two.

I'm expecting a shipment of components soon which should get me started on a lot of smaller things I've wanted to do for a while, which will also hopefully end up posted here. One of them is going to be a guide for transitioning from Arduino to AVR, using all open-source hardware and software. Hopefully this can help other people making the plunge as I am.

I've got a couple of other things in the works that I'm keeping under wraps for the time being. One of them should be announced in the next couple of days, and I'm very excited about it. The other is a new project, but I have no idea if it will work. I'm going to wait until I've got a working circuit before I post it, but if it does work, I think a lot of people will be interested in it. Keep watching the blog for updates.