(F)Light Suit Major Components

The main components of the (F)Light suit:
(Updated 8/15/11)

Component(s)	Source	Status
LED strips	DealExtreme	22 strips with connectors, need sealing and velcro backing.
8-channel MOSFET Output Boards	DorkbotPDX board order	Three built and tested, work perfectly
Arm accelerometers	Modern Device	Left one on main board, right attached with 3-wire lead across shoulders
Black flight suit	Amazon	Needs velcro for LED strips
Arduino-compatible main board: Minimalduino 105	DorkbotPDX board order
Arduino interface board: Adafruit protoshield	Adafruit Industries	Done, ready for mounting and cable threading. Ports for MOSFET output boards, right accelerometer, remote control, audio sensor
Remote control	homemade, various parts	Needs laser-cut acrylic surround, rot 2 flaky
Batteries	eBay	12V, 4800mAh Li-ion battery packs with barrel connectors, powering third MOSFET board.
Audio input: ZX-Sound board	RobotShop.com	Test, add light, change connector, paint, velcro back
Missing anything?

What is "Minimalduino"?

I started working on the "minimalduino" design as...

1. a minimal hardware design for an Arduino-compatible board. At heart, it is very similar to the Dorkboard, but
2. designed to match the form factor of the "official" Arduino boards so users can benefit from the many, many shield boards designed to fit on top. While (awesome) boards like EMSL's Diavolino are also low-cost and shield-friendly, I wanted to explore
3. optional hardware configurations, with different power connector options (pin headers, JST connector, barrel jack, screw terminals, or mini USB jack), 5V and 3.3V power regulation and optional voltage switching and regulator bypassing, and options for crystal and caps or a resonator. I also wanted to have
4. better shield-friendliness by placing LEDs (power and D13) and the reset switch (side switch or top switch) at the edges of the board, and lastly, I wanted the board to be
5. single-sided, home-etchable with wide traces and minimal jumper wires. There is still work to be done to reduce jumpers, but it improves on the the S3V3 "Severino" board which doesn't match up size-wise (it's bigger), the standoff mounts don't match, and it uses a DB9 serial connector instead of the now widespread FTDI USB-serial breakout cable.

Minimalduino 105: Nice!

I built out one of the "V.105" boards I got a few weeks ago from the DorkbotPDX PCB order, and it works beautifully, almost identical to the version 107 I posted files of, with "5V/3.3V" voltage and "FTDI/IN" power selector switches. I mounted a mini USB socket and a 7805 regulator, in addition to the barrel jack for power in.

I've gone to whole number versioning btw, no need for "always under 1" versioning or major/minor versions, and if I need to go higher than 999 (huh?!), I can just use four digits.

Top and bottom labeling came out great, including the Open Hardware logo, though the letters mush together a little. Also, the "FTDI" header label didn't print at all, maybe there's a problem having two "FTDI" text labels.

One issue is that the drills for the main female headers are smaller than those on versions 89 and 97 boards, even though they use the same parts in EAGLE! I'll check the parts and maybe swap them out. That's a bummer-- I had to drill them all out to mount the headers, which ripped some of the pads off the fiberglass, but thankfully they stayed connected to the traces.

Minor edits for the next version:

• Move the power input components to give electrolytic capacitors more room to accomodate shorter/fatter ones or taller ones mounted horizontally. As it is, the 100uF cap at the input is jammed between the .1uF cap and the barrel jack. [done]
• Rotate LED's so they can be mounted horizontally for better side viewing when using a shield. [done]
• Add heat sink polygon and vias under the 7805 tab.
• Fix the Sparkfun mini USB through-hole part: its outline is on the bPlace layer, not tPlace where it belongs. Or just use a different part. [done]
• Check female header drill diameters.
• Add 2-pin header at the reset button to make it easier to add a remote panel-mounted reset button. [done]
• Round the corners; looks nice on the Freetronics boards. Also check Uno outline and drills to make sure things are lined up right. [done]

I'm pretty happy with this for now though-- I have plenty of cheap, homemade, 5/3.3V-switchable Arduino-compatible boards to work with!

MinimalDuino 107 Pattern

After submitting the 105c version to the DorkbotPDX PCB order, I mentioned I'd make one at home, but the traces looked so thin on paper and I didn't like the routing of gnd to the crystal area, so I made a few changes to optimize it for toner transfer and home etching.

Here's a shared folder with the updated, v107 EAGLE files and a 600dpi jpeg for toner transfer. See the low res at right, or click for higher res; get the full res jpeg here.

Minimalduino v.105: Curvy Trace Fun

I've been trying out some Hope RFM12B radio modules-- very cool and inexpensive!-- which run off 3.3V. I've been using MinimalDuinos since they're 5V/3.3V switchable, and I got three version .97 boards made last year, with curvy traces, and they're coming in handy.

I have a few boards I'll need to get made over the next few months, so to warm back up with EAGLE, I polished up a straight (normal) trace version .105 board and set to curving it up. It took about an hour and a half, going around trace by trace in move mode, lots of command-clicking and dragging in the middle of trace segments to adjust their arcs. I submitted it to the DorkbotPDX PCB order before the deadline hit, and I can't wait to see what I get :) Design files and snapshots can be found here.

A key goal of the design is to have a good single-sided pattern for home etching, so I'll also make one by hand after fattening up as many traces as possible.

V.105 with straight traces:

Compare to V.105C, with curvy traces:

Minimal*duino V.96

I've done a little work on my "Minimalduino" Arduino-compatible board design lately:

• Moved the fourth standoff mount hole to line up with the Uno's new fourth standoff hole (which they didn't make aligned to the one across the way!).
• Fattened up the traces to make it more home-etcher-friendly: .016" and .024" traces, .018" min. separation.
• Spread out the components, reduced the jumper count, and removed the I2C header.
• Added pads for a mini USB jack, for power only. (I'm not sure about the grounded heat sink of a 7805 shorting to the 5V trace so I put in a solder bridge, but it's fine for making at home using real wires for the top layer jumpers.) So many options for powering this sucker!

Files can be found here.

Thinking about running this at 3.3V, I don't think it would work right for programming or for running with the FTDI cable attached.

Update: I had some v.97 boards made (DorkbotPDX order ftw!), same as .96 but with curvy traces and a few parts moved a little, here's one assembled:

Rounded EAGLE Routing?

Trying to spread traces around, I wondered how the rounded wire bend routing options worked in CadSoft EAGLE. There's a free-form, spline sort of wire bend option, and I went around to all the traces on the latest minimalduino version (which needs a better name btw), widening and pushing and pulling traces to try to fill empty areas. Sort of looks hand-drawn, kind of hippyish. I was hoping to find a way to eliminate one of the jumper wires, but no luck. I introduced an air-wire, actually, but can fix that with a little nudging.

Not sure whether to get a few of the rounded or "normal" versions when the DorkbotPDX PCB order is due. I got the idea trying to arrange the traces in the lower left and upper middle areas, after working in some patterning in the diagonals. Your opinions are most welcome!

Update 5/21/10: The mail to Laen at DorkbotPDX never sent?! Went to mail him asking him if they worked out, and the mail was in "Drafts". Stayed up late Sunday night tweaking them and... crap! Guess I'll have to wait for the next order; had a 3-digit 7-segment display board too, based on an SAA1064..:(

Minimalduino v.89 Delivered

Three copies of my latest Minimalduino design (V .89) arrived today, fabricated in the DorkbotPDX circuit board order. I built one with all components and it works perfectly, with the exception of the 3.3V regulator having a different pinout than the 75LXX part I used in Eagle-- oops...

A SparkFun protoshield and Adafruit motor shield fit on top fine, but with very little (read: "zero") clearance over the tall capacitors I used-- they'll get some tape on top, and the next revision will use shorter caps or orient them sideways. Excited to work with my first factory-made board, I shot and posted some build pictures with a few notes.

To correct in the next revision:

• Fix 3.3V regulator (MCP1700-330) pinout,
• Lay out for wider/shorter or horizontal voltage regulator caps for better shield vertical clearance.

To add/improve in the next revision:

• 5V/3.3V switchable with a jumper on three pins (though it will limit power),
• Top pad and through holes under 7805 for better heat dissipation,
• Credits (CC, author names) on bottom silk screen,
• Optional resettable fuse?
• Optional on/off switch or jumper pins?
• Try to reduce the number and length of jumpers.

Minimalduino: Three, Please!

I got the latest version (.89) of my Minimalduino board to Laen at DorkbotPDX before the deadline this morning-- looking forward to getting three copies of it!

I met all of the specs I laid out in my original post, except there are no TX/RX LEDs and no SPI header. Keeping it exactly the same size as the Diecimila/Duemilanove meant more (and longer) jumpers than I wanted, but I like the layout over all, and the jumpers won't matter for the DorkbotPDX order since those will be 2-sided boards.

My favorite features are the button type options (top or side), power connection options (barrel or screw terminals, plus .1" separated pins), I2C header, and extra standoff mount-- the three Diecimila/Duemilanove standoff mounts never seemed adequate to me.

PPAC Fixes, Minimalduino, Timer

I've been busy lately and haven't had as much time as I'd like to tinker, but I've gotten things moving in the last two weeks and am overdue to post.

Hoping to show off the alarm clock a little, I brought the PPAC (including power block, valve tree, and tank) to the Make:SF Meetup last month, and while talking and hooking it up at the same time, plugged the AC supply into the DC power socket! The voltage regulator fizzled but the power board seems fine otherwise. Strangely, of all things, the LCD display was dead as well... though I may have killed it when disassembling the can..:o I ordered a better looking LCD replacement which I'll install in the next few days-- green-on-black instead of black-on-green: Newhaven NHD-0216K1Z-NSPG-FBW-L.

The minimalduino project is still moving forward: I'm using a test board I made at home a few weeks ago, populated with as little as possible: chip, caps, resonator, female headers, reset and male FTDI header. I'll move a few traces around but it's pretty much there, and hope to get three test boards made through the DorkbotPDX PCB order, deadline noon on March 29. I've built a spreadsheet with costs, and it seems like I could make a batch of 25 kits at just under $15 each. I'm not sure if it's worth the trouble though.

A few weeks ago, I built a new coffee grinder timer with a re-worked sketch and single board, then handed it off to fellow coffee fiend HF for ideas on how to make the ideal grinder timer. One thing we agreed on is that tenths of a second would be cool, so last night I had a great time working out a sketch to drive a common anode 3-digit 7-segment display using an SAA1064 IC. Of course having a sketch to start with made things straightforward-- thanks Alessandro Saporetti! I reworked the code to make it more general purpose, using all of the chip's functions including multiplexed (versus not) and changing the constant current output (7 output levels possible, from 3 to 21mA). [Video to come]

Minimal*duino

I reworked the one-layer board to got everything routed nicely in two layers, and etched it last night with the layers very well aligned! Now to get flux-- without it, the vias need their own little lead, which is quite a pain. I'll build it out today and test it, then look at board house prices for making a minimal order, seeing how many I'd have to order to get the price down to $10/kit (with no extras). I wonder about rebuilding it in KiCad though-- I've about had it with EAGLE's inefficient UI.

Minimal Arduino?

I prefer breadboard-friendly Arduino-compatible boards like Boarduino and iDuino, but I keep wanting functionality people have built into shields like Adafruit's Motor Shield and Batsocks' TellyMate Shield.

All I want in an Arduino:

• ATmega328
• FTDI programming header
• Arduino "form factor" with odd D7/D8 spacing and standoff holes

Sorting my Arduino-compatible board spreadsheet first by price, then by form factor, it seems the lowest price for a shield-compatible board is ~$17 for a serial Freeduino, compared to ~$10 for a Dorkboard, though the latter comes with an ATmega168, not a 328.

Necessary items:

• microcontroller: ATmega328, socket, capacitor
• clock: oscillator and 2 caps, or a resonator
• reset: 90-degree (side) button, 10K resistor
• FTDI cable interface: 6-pin header, capacitor
• Power: Barrel connector, 2-pin header

Extra interface header pin pads:

• icsp (2x3)
• i2c (4)
• spi (6) (nah)

Simple extras, parts not provided:

• Power indicator: LED, 1K resistor
• TX/RX indicators: 2 more LEDs, 2 more 1K resistors
• Power regulation: 7805, 2 capacitors, jumper
• Diode to prevent inverted power hookup

I'm traveling for the next month so this will be a fun little layout project, perhaps as a way to learn kicad (as opposed to EAGLE, which I currently use) and to explore board house pricing and specs. The goal is to be able to produce a $10 kit (cost), which may be possible given how many goodies SparkFun includes in their $20 Arduino Pro 328.

Update 12/29: I got a single-sided board laid out with just four jumpers, and I'll tear it up and redo it with the programming header where I want it, jumping TX and RX across the board. The files for the "Severino" single-sided board helped me figure out the routing.