Start It Back Up, Boss

So I had a nice little surprise today when the shear cutters I ordered arrived a day early. That, combined with picking up the final resistors I needed from Radio Shack, let me finish up the Unsped shield (with the exception of the headers on the breakout board) and solder the diodes to the first SparkFun button PCB. I've included a couple of before & after pictures showing how the leads first cut with my old diagonal cutters, then with my new shear cutters.

Before:

After:

This should help the buttons sit properly. Finally, I inserted the 16 LEDs into the board and did a quick smoke test connecting each one directly to +5V with a resistor to make sure there were no issues with the traces or the LEDs themselves.

This is a pretty good view of one of the LEDs lit up. They're very bright (6000 mcd) even in a fully lit room. They do, however, have a narrow projection and you can see a somewhat prominent "dot" when you put the button pads on. I'm going to find a way to get the entire board lit at once before I do any soldering in order to check for any inconsistencies in color/intensity. I'll also experiment with sanding the tops in order to provide a more diffuse glow.

I'm heading out on vacation this afternoon and will be getting back Sunday night. Hopefully I'll be home in time to figure out a quick way to get the board lit by the MAX driver.

Production Halt

[note: the wires running from the breadboard to the PCB are not routed properly, an FYI if anyone tries to use this picture for reference.]

So I've been able to play around with the parts that I've received so far but have hit a bit of a snag. I was able to get some of the code featured on Basement LEDs post up and running to test button presses. One of the problems I ran into, though was that it would correctly identify the column of a button press but then it would think that it was being pressed across all rows. I've checked the connections on my breadboard and think that everything is wired up properly, so I suspect it might be the code itself. Anyway, this is just a test rig and I'll hopefully be able to move forward soon.

My real holdup is that I need a better pair of cutters before I solder the diodes and LEDs onto the Sparkfun boards. Right now I have an old pair of diagonal cutters that leaves a fairly long lead. Aside from being a neat freak with my connections, I've seen that I'll need to get the diode leads as short as possible to make sure the button pads don't ride too high. I've got some shear cutters ordered from Amazon that will, hopefully, arrive before I leave for vacation this week. Other than that I've got the breakout board mostly soldered and will try to get as much as I can together before I leave.

One of the other ideas I've had as far as customizations go is utilizing the analog inputs for extra controls. I'm kind of looking at it from an Ableton Live-centric point of view right now. I'm going to look into the possibility of adding a couple of pots to control things like global tempo, quantization, mixing channel, etc. I think I'll be able to use this post on the monome site regarding adding an accelerometer as a basis for moving forward on the add ons. The only thing I'm really not sure about at this point is whether I want to include any kind of additional functionality in a single enclosure or make a separate module.

Parts are in!

So I got my orders in from Sparkfun, Curious Inventor, and Digikey today. It's like a mini geek Christmas. I'm still waiting on the 24 pin DIP socket that was back ordered and to receive the LED driver samples from Maxim. I also realized I was looking at the resistor network the wrong way (misread the schematics and thought that it was inbetween the MAX driver and the LEDs, not the shift register). Since the cheap side of me finds it galling to pay 4 bucks shipping for a .23 cent part, I decided to make my own ghetto resistor network.

Aside from my crappy soldering, I realized that I had picked up two different sets of 5 resistors from Radio Shack. They conveniently mixed 100 ohm resister packs with the 100 kohm stock. Thanks guys. So I have 5 resistors soldered (poorly) in parallel and need to pick up a new set to finish it off.

Besides that I decided to start putting together some of the parts. One of the things that I noticed is that the cutters I have leave the diode leads pretty high on the Sparkfun board. This causes the button membrane to sit high. I've only soldered one diode so far, so I'm going to see if I can get a set of flush cutters to prevent that from happening.

I've been going through the designs that are out there as well as the arduinome firmware and have some ideas of how I'd like to differentiate my build from the "standard" arduinome. I'd like to be able to have the unit be able to run in a sort of "light toy" mode without being connected to a computer. Off the top of my head I have the following in mind:

• Wire a rocker switch to the arduino power jumper to be able to draw power off of a wall wart
• Have an opening in the enclosure to allow the power jack to be accessed (obviously)
• Update the firmware with with an "unplugged" mode. This would essentially set a boolean during setup based on the value of Serial.available() and run some custom code present in the firmware that is yet to be determined.

Parts List

I have my initial batch of parts ordered. There are still some parts that I have yet to order for various reasons. Also, I went ahead and got a few extras beyond what the build requires just in case.

SparkFun

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4	Button Pad 4x4	$39.80
4	Button Pad 4x4 PCB	$39.80
	S&H	$6.95
	Subtotal	$86.55

Digi-Key

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2	MM74HC164N PI/SO Shift Register	$1.08
2	MM74HC165N SI/PO Shift Register	$1.08
70	1N4148FS Diodes	$2.24
1	ED90053 24 Pin Socket (Back Ordered)	$1.53
1	ED90049 14 Pin Socket	$0.89
1	ED90050 16 Pin Socket	$1.02
3	P4910 .10 uF 100V Monolith Capacitor	$1.68
1	P828 10 uF 50V Capacitor	$0.16
1	S1012E-36 36 POS CONN HEADER	$1.68
	S&H	$4.80
	Subtotal	$16.12

Curious Inventor (They had some of the Unsped arduinome shields left from a batch order)

---

1	Unsped Arduinome Shield PCB	$5.00
	Shipping Round 1	$5.99
4	16 Pos IDC Headers	$1.96
1	5 Ft 25 Pos Rainbow Ribbon Cable	$4.99
	Shipping Round 2	$5.99
Subtotal	$10.99

Maxim-IC

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2	MAX7219CNG+ LED Driver Samples	FREE
	Subtotal	$0.00

Stuff I Already Had Lying Around

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1	Arduinome Decimellia
100	Blue 1000 mcd LEDs
	Misc wires

Radio Shack (ugh)

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2	100 kohm Resistor 5 Pack	$1.98
1	22 kohm Resistor 5 Pack	$.99
	Subtotal	$1.98

Grand Total

$129.57

I still need to figure out exactly what value resistor network I should pick up, but that should only add a few cents to the total. This also doesn't take into account any sort of enclosure. I'll keep updating this as I move along in the process.

[edit 3/23/09 1:14 PM CST: Added resistor cost from Radio Shack]
[edit 4/19/09 6:54 PM CST: Added 22kOhm resistor from Radio Shack & ribbon cable from Curious Inventor]

Yet Another Arduinome

Alright everybody, I think I'm ready to start building my very own arduinome. I've been looking around the tubes and found lots of helpful resources that I will shamelessly steal from due to the fact that I'm essentially a complete noob to the electronics scene. The only semi-interesting thing I've done so far is create a simple set up using one of the analog ports on my arduino to read the value of a potentiometer over a serial port and post the value to Twitter using a custom Python script. The intent was to be a proof of concept for posting the temperature of a remote location to Twitter, with the pot in place of the temp sensor. If anyone ever ends up reading this and is interested I can post the (unpolished) code.

Anyway, while the arduinome has been done many times in the past I've got some ideas that might be able to set it apart. Assuming I can figure it out, I was thinking of including the ability for optional external inputs, not unlike what is offered by the Machine Collective but without quite as much awesome. I figure for now I'll stick with the monochrome model and, if I can get everything blinking, think about an RGB model in the future.