Wow. The Imperial March never sounded so good. Stepper Motor Driver works! The stepper motor driver test program was loaded into the Sanguino motherboard using USBtiny from adafruit. I switched from parallel STK200 programmer to usb based USBTiny programmer in hope of using the arduino IDE to upload the reprap firmware sketches however I am still having difficulties loading programs into the Sanguino motherboard using the Arduino IDE.

The NEAM 23 stepper motor is from Makerbot and costs $28.00 each. Too bad the stepper motor is not made in a free and democratic country. Anyone know of a US source for the Nanotec stepper motors?

After many days of futile attempts to upload the firmware . . . . I finally succeeded in uploading the reprap firmware through arduino ide. Originally though I was unable to load the bootloader through arduino ide, I was able to upload it using commandline avrdude. The error message I received through arduino ide is,

avrdude: stk500_2_ReceiveMessage(): timeout

I did not know if the error is due to assembly/soldering error or from improper arduino IDE setting. Since I can view the ATmega644p setting and upload the bootloader with avrdude I lean toward a misconfigured arduino setting. I tried the reprap forum as well as googling for solutions, but still could not solve my problem. I came across a blog that mentioned improper baudrate setting and I started to experiment with different baudrate setting using avrdude. I found that only 115200 seems to work and other baudrate settings gave timeout errors similar to the error from arduino. I ended up inserting

sanguino.upload.speed=115200

into my arduino board.txt file and following the upload instruction with the obligatory reset the firmware loaded, the green power led lights up and I was able to turn the ATX power supply on with the reprap motherboard on/off switch. Wow!

Next is to test the stepper driver and extruder board

Fat Tux Leather Coaster was designed using Inkscape by modifying the original Tux sgv file. Rectangular vegetable tanned tooling leather plates were obtained from a local leather craft supplier, Tandy Leather Factory. The reason for choosing the rectangular shaped leather over round leather is because the rectangular ones are made in the USA, which turns out to give additional design flexibility in profiling the actual coaster, though it does take more time to cut the profile.

To fatten up Tux for a better coaster shape, a circle was drawn over the original sgv file and various points on Tux were moved tangent to the blue circle to achieve the final "Fat Tux" shape. An second concentric yellow circle was used for company name placement and finally the red outlines was created for the final coaster profile.

The coaster was created using 3 different laser engraving/cutting profiles. The first is the raster engraving of the Tux shape, the second is a slightly lower power raster engraving of the company name, and the third is an almost full power vector cutting path to separate the Fat Tux Coaster from the rectangular leather block.

Issues that need to be resolved includes how to removed the organic burnt leather smell from the cutting, though the smell does dissipates after a couple weeks. Future improvements includes cutting the profile with a clicker instead of using the laser.

The finished product can be found on TheCuriousPenguin.com.

One of the three stepper motor drive V2.3 board along with motherboard V1.2 has been completed but I had trouble getting the Motherboard to show signs of life. I was able to load the bootloader through avrdude with a parallel port programmer from Sparkfun but could not get the arduino IDE to work properly. It took a while to convert the 10 pin isp to the 6 pin isp format, which basically was just remapping of the MOSI, MISO, VCC, GRD, Reset, and SCK.

I don't quite remember how I came across Atmel AVR microntrollers. Pre AVR days consists of handyboard, then some PLC kits, then a Basic Stamp kit, a smudge of embedded Linux somewhere in between, and finally the AVR days arrived. The concept of automation was always in the back of my mind but all of above ventures ended up gathering dust somewhere. Running Linux made things a bit more challenging, often beyond my meager skills and my short 30 seconds.

This image pretty much shows my tortuous and slow progression through various AVR incarnations. I started with STK500, then the C Programming Book for Microcontroller base on the AVR Butterfly, then Sparkfun's tutorials using the ATMega16, then a one day affair with Arduino through The Public School's Practical Electro-Mechanical class. Finally, with reprap generation 3 motherboard powered by AVR, I am going through Sparkfun's tutorial again but this time kind using the less expensive ATTiny2313. It's the least expensive AVR microcontroller with the external oscillator capability. Looking back I wish I had discover AVR sooner. It seem to be the least expensive but most versatile option.

Hopefully all the puzzle pieces will converge one of these days. . . .

The laborious task of kitting together the Stepper Motor Driver V2.3 is done. Though I just discovered that Stepper Motor Drive V3.0 is in the works. It looks like the stepper motor driver IC will be changed from Allegro A3982 to A3977. I haven't progressed far enough in my microcontroller circuit building to understand the different but a quick search says something about A3977 gives a 25% increase in peak current. The cost for Stepper Motor Driver V2.3 is as follows.

Hackerspace documentation states:

"The rule of thumb is 2+2. You need a partner to get the initial idea kicked off, making two of you. You need two more people in order to get real work done. Don’t start before you are at least four people. From this point it’s easy to recruit more people. Aim for ten people for a start."

Anyone else interested in setting one up in the the Pasadena/Arcadia/El Monte area of Los Angeles, California, USA.

The hackerspace wiki space can be found here

Most of the parts for building the 3rd generation Reprap electronics have arrived and the cost of the mother board is listed below. Too bad Makerbot is out of stock on their motherboard kit because it took hours spanning several days to order, receive, sort, and group all the parts from three different vendors. . . . and this is just for the motherboard, I haven't even started kitting together the 3 stepper motor drive boards.

Taking the plunge head first into a shallow pool is the result of not reading through the reprap documentations more carefully.

I finally have the electronics portion of the extruder controller V2.2 assembled. . . I thought the initial reflow soldering was passable until I took some desoldering wicks to the SMT chips and took out almost half of the visible solders. Yicks!

Anyway so I have an assembled extruder controller V2.2 only to realize that the Arduino based reprap controller I was so fixated on is old gen2 technology. I've been itching to try out my Arduino board ever since I took the practical electro-mechanical class at ThePublicSchool. Unfortunately, the new gen3 electronics no longer uses Arduino as the main controller and instead uses Sanguino. Gen3 electronics is also "cleaner" looking with integrated power circuit from the main controller board to the peripheral boards such as as the extruder and stepper motor drive via RJ45 connectors.

Arduino, Sanguino what's the difference right? They're both AVR based with Sanguino having more I/O pins and memory. . . probably some other useful stuff as well but I'm still in the AVRTiny phase so that's as deep as my eyes can read and brain can absorb.

Going back to taking the plunge part. So I have the extruder controller with no way to test it. To get around that problem I ordered as many parts as I can to complete the electronics portion of the Repstrap build. Once all the components arrive I will give a cost summary for the electronics portion and start working on the Sanguino based motherboard.