How To Make Almost Anything Class

Lassiter's WEEK #5 Assignment



The assignment for this week was to mill a "Hello World" board , stuff it and program it. 
I have milled many a board to date, but never one that worked.  Or at least, they disappear 
before I can test them so I've never known whether or not they worked. Plus which, historically,
I had to make my own cables, and have not yet  succeeded in making a working cable.  So the fact 
that cables were provided for this week's assignment was most encouraging.  

Downloaded hello.sch, hello.brd, and hello.asm from fab.cba.mit.edu/fab page.  Opened hello.sch in 
Eagle program.  Processed the board such that layers 1, 17 and 18 were selected and by doing so
created a hello.cmp file.  Opened hello.cmp in the cam tool and contoured the boundaries, rastered 
the interior and created my hello.rml file. 

Milled the file on the Modela MDX20 machine with no difficulty. I cheated and used the PHM machine 
and did not experience the same difficulties as the rest of the class. Seems the machine in the 
laser cutter space is having trouble-- bed uneven.  Have ordered a new Modela for the laser cutter
space.  

Stuffing went fine, Neil's trick of putting solder on the copper leads first before attaching the 
component made the process go very very quickly (compared to what I am used to anyway!).  Had 
some troubles with cables for programming.  Seems the good cables were never made, so we had to hunt 
around and make cables. Shani made a sucessful pair of cables so we used hers.  

Opened rx.py to get the program running.  After attaching both cables-- one for power, one 
for programming, I attached the 8 pin clip to the microprocessor.  After many attempts to hold the
clip perfectly on top of the leads on the microprocessor, I typed the avrdude in circuit programmer code 
into the linux shell,hit return, and "Hello World" typed out nicely on the computer screen in rx.py.
I decided to changethe program to read "Voila!  Success!".  To do so I had to open the hello.asm file (Ithink it was that 
file) in Kwrite, change the programmed text to be "Voila! Success!", saved the file, and then
reprogrammed the board via cable and avr language to read "Voila! Success". And succeed I did.  

What a relief!

Here is a picture of my Voila! board, and of an efe board I milled this week as well.

Hello/Voila and Efe boards.



UPDATE on Final Project

This week I found the sonar board files on the Norway site. I milled the boards and had a bit of a problem with the Receiver board-- Ithink the end mill on the Modela broke about 2/3rds of the way through. The Transmitter board milled perfectly. I am concerned that the copper traces on the boards are too thin/small. The are quite small, and in looking closely at the surface of the boards you can see little gaps in the copper traces. Which I suspect is not a good thing-- might not allow electricity to pass. Will need to check with more experienced folk. Also, not sure I processed the board correctly. I found lots of different layering options when I set the cmp file up, and I could easily have not selected the right layers. I choose the same as for Hello World-- 1, 17, 18-- and this may require something somewhat different. I am wondering if the unidentified pads on the circuit boards are the places that one connects the ultrasonic devices. I'm betting yes. also, how to power them? Need to look into batteries. This just in from Yvgne: The sender were powered from battery, but the receiver used a adjustable power supply that we took from Troms University College. Both boards used the "large" power connectors. The ultrasonic parts were soldered directly on the circuit board, after drilling a hole for the pins in the soldering pads. Dag Hkon made a library part to Eagle for making the pads, but i'm not sure where to get that file. You might be able to open the board file and copy it from there...or send a email directly to Dag Hkon asking for it. If you find a smart way for connecting the ultrasonic parts temporarly to the boards (without soldering) please let us know... I'll try to take some picture of what we have/had, it should not be to hard to get that. We have quite a lot of things that has to be done before the ultrasonic rangeing is ok. The first/biggest problem is to syncronize the start of the ultrasonic burst from the transmitter with the timer in the receiver to get the correct flight time through the air. This is very important to be able to calculate the range correctly, and we have been thinking about using infrared light to transmitt the syncronizing pulse (or request from receiver to transmitter about starting sending the ultrasonic burst). I think that there was some project using infrared light in Boston, but I have checked this out yet. Our progress on LPS has not been to great lately. Still, I'm working mostly with the assambly programming and Dag Hkon mostly with the electronics (and the board and schematic). Keep us posted about you project! Best regards Yngve As for the solenoid/linear motor-- no progress this week, other than to determine that this is in fact what I want to try to make and use for the heart. I will try to get the parts and get started on a motor this week. Also will design a prototype for the telescoping mechanism this week.

TX13 transmitter board and RX1 reciever board from Norway.