BRICKSHIELD EXTRAVAGANZA!!!!

So we're calling it the BrickShield now. Don't want to get an angry phone call from the lawyers at Lego, or even worse, some kind of cease and desist.

But it's done! I actually got the PCB back from batchPCB a while back, but have been a little too busy to post about it. Here it is, Start slobbering.

Power select jumpers on the right

You can see it has the Mindsensors NXT port I posted about earlier. This is connected to the TWI pins for "easy" communication with standard NXT devices.

Yellow wire coming from the V+ line

One of the big things I wanted was MORE OUTPUTS, so now we've got simultaneously:

-4 Amplified Digital outs (total of 4 pins on left)

-4 Amplified Motor Outs (total of 8 amplified pins on right)

-4 Servo Ports (below the NXT port)

-Digital lines 0 and 1 available for communication with PC or Radio

-Header for BlueSmirf at top

-Passthrough headers for mounting another shield on top

-Integrated V+ port for higher voltage in drivers

-5V/V+ selection for each via jumper (Servos, Digitals, Motors)

-Optional ICSP pass through for powering additional boards with the 5V line

-Offset header slot on the digital side to allow use with standard perf-board

-Extra 5V an 0V lines by the analog inputs for easy sensor powering

Anybody recognize the LED board on the right?

Below you can see what it looks like with the Libelium Xbee Shield (which I use frequently for RC Projects). If you so choose, you can forget the communication shield on top and just control the Arduino and Brickshield straight from your PC using Arduino Animator.

So I'll be sending these off to a couple of distributors to see if they're interested in selling them. Probably will start with Sparkfun, Makershed or Mindsensors and see if they are interested.

If you'd like to see this as a product you can buy, leave a comment.

LegoShield Updates

Sean and I are currently working on improving our Lego Compatible Shield.

Here's an early look at the PCB.

This version will sport:

• Voltage jumpers rather than switches. I noticed the switches I used on the last version were way underrrated.
• Can type Capacitor for battery stabilization
• NXT Header for connecting to the mindSensors NXT host cable. This will make it easy for anyone to connect their arduino to the NXT Sensors.
• Reset Button Brought to top
• 5V and 0V Rails next to the Analog In bank
• BlueSmirf Header for Bluetooth Connectivity (not shown in photo)
• Pulldown Resistor on the Enable Line
• VRaw will be connected to external power (don't reverse the leads, folks!)
• adjustments to the Lego Hole Sizes

Hopefully we'll be ready to send them off for fabrication soon!

Lego RC with Xbee

I've had a conundrum for a while. How to control my RC projects with a ready-made, swappable controller and power board. Many of my recent projects are Lego based, but some are not. My objectives were:

CONTROLLER:

Dual Analog

Dials

Buttons

Toggle

Extra outputs to allow expansion (serial to LCD screen)

Vibration

9V Powered

MOTOR SHIELD:

More outputs than other motor shields

Use XBee devices.

No tunneling

Hot swappable without reconfiguration

Make as an Arduino shield (to avoid reprogramming)

Servo Outputs

PWM (analog motor) outputs

Digital Outputs

Outputs should be amplified

Integrated trimpots and switches for easy configuration

Technics (Lego) hole compatibility

I set off designing the controller board first. I ordered some components from Sparkfun and got the rest from my local electronics store (Elliot Electronics for those of you in Tucson). Some of the components are from DigiKey as well

I based this design on the atmega 328 surface mount board. I built it from the ground up as a non-shield design, but it's basically an arduino without the USB interface.

Normally I use BatchPCB available through Sparkfun.com to make my PCBs, but this time I tried PCB-Pool. That's why the board looks different.

The output from this board (over XBee) will always be the same. Short packets sent out in API mode to whatever remote device is attached to the other Xbee unit. For convenience sake, I used the Xbee API mode library located here : http://code.google.com/p/xbee-arduino/

Thanks Andrew!!!!

After I got the code working all Peachy-like. I started on the other end of the project. The motor shield

I figured by using some clever programming, i could leverage the existing servo and PWM outputs into a ton more. Using a shift register and some switch logic, I expanded the outputs enough to get:

4 PWM Motor Ports

4 Digital Output Ports

4 Servo Ports

TX and RX unaffected on pins 0 and 1

an enable port (pin 13) to avoid startup jittering

So far I haven't had a chance to mount it into an actual project, but I've got a couple projects at the house waiting to be powered up. As you can see in the video, though. The outputs work great, and using the Power Functions Kit and some Servo brackets (mindsensors.com). I can get more devices attached than by using NXT!

Rocket Chute Deployment

I have a friend who does model rockets as a hobby. He was looking at getting an off-the-shelf deployment module for adding a parachute to his project. I mentioned that we could do it with an arduino and some sensors.
I had him check digikey.com for a cheap altimeter, and we found one for $7, but the lead time was too long. He's moving pretty soon, so we needed an immediate solution. I decided that we could use an accelerometer, and when it reads 0-Gs on the vertical axis, we'd know it was free-falling. (or had ended acceleration)

We set up a timer that would deploy the parachute a given time after the acceleration ends.

The red and blue wires arm the device. These get twisted together after you get the rocket set up. so it won't go off unexpectedly. The device also monitors the nichrome ignition wires. If one of the wires gets broken, you can tell from the LED indicators on the bottom.

Here's the underside of the board. I drew it up in EAGLE and etched it in the shop at work. You can see it's a little on the hablich side, needs a dose of alcohol and it could also use a small redesign. I noticed after I got the software running that a couple of the outputs were configured wrong in the hardware. If I ever make a V2.0, it'll be a little more attractive.

Hopefully we'll be able to test it out next week after I get back from Mexico.

MC Animator

This video is about the makingthings microcontroller. It's a pretty cool little device.
I wrote this program to take advantage of all its inputs and outputs.

If you decide to run this program, make sure you have the controller connected up through ethernet, and that you get ethernet response over mcHelper.

the program and source are available at http://www.makingthings.com/Members/tunell.

The microcontroller costs about $110 and is AWESOME. I've been using it in a lot of my projects, and it's great! Don' t know how I ever survived without it.