Generation 7 Electronics Development
Posted by Traumflug
|
Re: Generation 7 Electronics Development December 03, 2010 07:59AM |
Quote
i want to ask if the board is intended to be suitable for diy purposes.
Yes, being suitable for DIY and being reprappable is the whole purpose of this "Gen7" variant of electronics.
Quote
i would like to point out to situations like the red circles in the picture [www.reprap.org] and its fairly usual that the drill holes almost cut the traces they are onto. At which degree that can be regarded as an issue that remains to be decided for each individual, but i would rather put the traces slightly off-holes.
Another, more PCB-design-software compatible way would be to make the pads around such holes bigger. BTW., this picture doesn't show a Gen7 board, right?
Quote
However stuff like this is more like a "polishing" phase once the layout is pretty much decided on.
Quote
Another thing is i imagine at least some peoples could / would want to try this with their own different stepper boards then will have to takeout the signals (step, dir, enable, gnd etc) out to their board(s).
How about using a male connector (like it's packaged with the Pololu boards) and sticking that into the female connectors instead of these Pololus? If you don't have the males, solder an inch of copper wire to the tip of your flexible wire. Works just nicely here.
Quote
On the general picture, this being almost single sided, at toner transfer i would make the bottom layer ground plane (mostly). Ofc microstripping wont reach the elevated stepper drivers where it could of been of some use, but it wont be bad either. The board design could go as much as rely on bottom as gnd plane and take out all gnd lines from top to simplify it, but that can be regarded as extreme and i cant say if clearing resulted on the top would be worth the effort, but maybe it is worth a shot to see how it comes up like - up to you ofc.
Sure. Feel free to find a better tracing of the board. Particularly, I'm impressed by the tracing of the Repic board. Perhaps we can learn something here.
One question from my side: How did you get the board in your picture so nicely tinned?
| Generation 7 Electronics | Teacup Firmware | RepRap DIY |
|
Re: Generation 7 Electronics Development December 03, 2010 09:05AM |
No, the picture with the hole in the trace is the 3.3v stepper driver board, shown on this page [www.reprap.org]. As off-topic, incidentally i also need some tuning help on the board in picture here [forums.reprap.org] I have tried 3 different motors on it, and while i found that getting them to run acceptable isnt really hard, but getting correct math values seems to be. I have some points where my theory results seems to have no clue to where reality is, so i guess i am making a few mistakes just cant seem to find the way out.
The tinning is simply done with a solder wick imbued with solder and passed over traces with a big iron, and as step 2 if it lays excessive solder, then a clean wick can be used to clean it up. Also alternatively without wick, with one of those big iron guns that use a thick copper wire as heated element, i had one wire like that brushed against a sand paper to flatten it a little, activate the tip, then putting only a small amount of solder and passing over the board gently. Needs just a little training so after a few boards it starts looking better and better. Prior use of SK-10 calofonia spray on board can help. Also there is a tinning chemical, but that is expensive stuff and also once prepared has a limited life, so i dont see any reason to use that.
+found a youtube vid for that kind of tinning here [www.youtube.com] and added it to the page, its sort of how i do it except right after removing the toner with acetone so copper is not oxidized thus no need to clean it, and i use one of those high power iron guns that resembles a pistol and has the wire as heated element instead, i find it much better for this job as it can cover bigger areas faster and easier
Back to on topic, most of time, doing some toner transfer boards in house, i find alot of pcb layouts to need some minor adjustments, most frequent being a hole cuts a trace (coz commercial ones are plated through so they dont care for that aspect), or a thin line comes off during some soldering on it or on a component that is on it (i suspect that depends on substrate too, i think fr4 fiber glass or w/e it is adhere differently to copper side than other substrates, but cant say for sure). Frequently i get myself into situations like "if i only have had done *that* before etching i wouldnt of had this trouble". So, having met situations like those i usually try to anticipate them beforehand when thinking of doing something. I guess in time that turned me into a little minor-changes obsessed dwarf so i could be exagerating a little
Edited 2 time(s). Last edit at 12/03/2010 09:22AM by NoobMan.
The tinning is simply done with a solder wick imbued with solder and passed over traces with a big iron, and as step 2 if it lays excessive solder, then a clean wick can be used to clean it up. Also alternatively without wick, with one of those big iron guns that use a thick copper wire as heated element, i had one wire like that brushed against a sand paper to flatten it a little, activate the tip, then putting only a small amount of solder and passing over the board gently. Needs just a little training so after a few boards it starts looking better and better. Prior use of SK-10 calofonia spray on board can help. Also there is a tinning chemical, but that is expensive stuff and also once prepared has a limited life, so i dont see any reason to use that.
+found a youtube vid for that kind of tinning here [www.youtube.com] and added it to the page, its sort of how i do it except right after removing the toner with acetone so copper is not oxidized thus no need to clean it, and i use one of those high power iron guns that resembles a pistol and has the wire as heated element instead, i find it much better for this job as it can cover bigger areas faster and easier
Back to on topic, most of time, doing some toner transfer boards in house, i find alot of pcb layouts to need some minor adjustments, most frequent being a hole cuts a trace (coz commercial ones are plated through so they dont care for that aspect), or a thin line comes off during some soldering on it or on a component that is on it (i suspect that depends on substrate too, i think fr4 fiber glass or w/e it is adhere differently to copper side than other substrates, but cant say for sure). Frequently i get myself into situations like "if i only have had done *that* before etching i wouldnt of had this trouble". So, having met situations like those i usually try to anticipate them beforehand when thinking of doing something. I guess in time that turned me into a little minor-changes obsessed dwarf so i could be exagerating a little
Edited 2 time(s). Last edit at 12/03/2010 09:22AM by NoobMan.
|
Re: Generation 7 Electronics Development December 12, 2010 03:35PM |
Traumflug Wrote:
-------------------------------------------------------
> If you have fixed them, I'll happily upload the
> results. Keep in mind, though, neither the good
> part of Lanthans great bunch of changes nor the
> fixes for the shortcomings mentioned a few posts
> above are uploaded (or even created), yet.
I'll work on it but I don't know when I will have time for that. We are having trouble with our nozzle and this has priority
But I will stay tuned because when we finished printing the Mendel parts the first Mendel will NOT use the gen 3 electronics
-------------------------------------------------------
> If you have fixed them, I'll happily upload the
> results. Keep in mind, though, neither the good
> part of Lanthans great bunch of changes nor the
> fixes for the shortcomings mentioned a few posts
> above are uploaded (or even created), yet.
I'll work on it but I don't know when I will have time for that. We are having trouble with our nozzle and this has priority
But I will stay tuned because when we finished printing the Mendel parts the first Mendel will NOT use the gen 3 electronics
|
Re: Generation 7 Electronics Development December 13, 2010 06:46PM |
Some thoughts about MOSFETS
I recently completed a milled pcb with the exact same MOSFETS circuit extracted from gen7 (my interpretation "gen 7 simplified", posted some time ago in this thread). I was able to verify it is working perfectly with arduino hardware PWM at 32 KHz (Timer1 library). Intention is to drive a small spindle.
Wondering if:
1) Might be a good idea to move those MOSFETS to a separate board after all. This would reduce clutter and dimensions of the motherboard. Added benefit: we could even select different voltages for different uses (example: the particular spindle motor I am using tops up at 27V)
2) Does anybody know about an equivalent of the Timer1 library for the Sanguino? Is it easily portable? Turns out it is a boon to configure PWM cycles with that.
Comments, ideas?
L.
I recently completed a milled pcb with the exact same MOSFETS circuit extracted from gen7 (my interpretation "gen 7 simplified", posted some time ago in this thread). I was able to verify it is working perfectly with arduino hardware PWM at 32 KHz (Timer1 library). Intention is to drive a small spindle.
Wondering if:
1) Might be a good idea to move those MOSFETS to a separate board after all. This would reduce clutter and dimensions of the motherboard. Added benefit: we could even select different voltages for different uses (example: the particular spindle motor I am using tops up at 27V)
2) Does anybody know about an equivalent of the Timer1 library for the Sanguino? Is it easily portable? Turns out it is a boon to configure PWM cycles with that.
Comments, ideas?
L.
|
Re: Generation 7 Electronics Development December 14, 2010 05:39AM |
Quote
korban
The only problem I have is I can't open the files on windows?
There's a Windows build:
[www2.eng.cam.ac.uk]
Quote
Could someone extract the copper layer and post it somewhere?
Doesn't make sense as of today, as there are still a few issues to be fixed. So you have to waste your time waiting instead of learning a useful OS, unfortunately.
Quote
Lanthan
Does anybody know about an equivalent of the Timer1 library for the Sanguino?
Hmm. What's the Timer1 library, what's wrong with it and to where do you want to port it?
| Generation 7 Electronics | Teacup Firmware | RepRap DIY |
|
Re: Generation 7 Electronics Development December 14, 2010 06:26AM |
To Korban: yes, any time invested learning un*xes is time well spent and finally pays off wonderfully.
Me:
>
> Does anybody know about an equivalent of the
> Timer1 library for the Sanguino?
Traumflug:
>
> Hmm. What's the Timer1 library, what's wrong with
> it and to where do you want to port it?
Timer1 library for arduino (atmega168, atmega328) http://www.arduino.cc/playground/Code/Timer1 , provides an unobtrusive interface to manipulate, well, timer 1 (arduino pins 9 and 10) settings, such as PWM cycle, attach interrupts etc.
I am currently testing stuff with an arduino. I was looking for something to modify the default PWM cycle setting for Timer1 (about 500 Hz) to about 32 KHz. This will come useful when pwm-driving a small spindle DC motor with the mentioned MOSFETS, and as implemented in the library, is a fire-and-forget operation.
#include "TimerOne.h"
const int ledPin = 10; // LED connected to digital pin 10
const int potPin = 5; // Potentiometer connected to analog pin 5
int potval = 0 ; // store value of pot here
void setup() {
Serial.begin(9600); // init serial comm
Timer1.initialize(30); // initialize timer1, and set period to 30 microseconds
Timer1.pwm(ledPin,0) ; // initialize PWM on pin 10 with duty cycle 0
}
void loop() {
int potval = analogRead(potPin); // read pot
Serial.println(potval) ;
Timer1.setPwmDuty(ledPin, potval) ;
// wait for x milliseconds
delay(10);
}
I agree this does not make any sense if you just want to drive a couple of heater resistors, but should you ever want to do some light milling with Gen7 electronics and some sturdy reprap design, you'd find uses to higher PWM frequencies.
Yes this can also be done by directly and-ing / or-ing some registers, but in a more involved way (IMHO).
So I went looking for more information on Sanguino / atmega644 pins ports and timers, but of course there is less documentation floating around, as compared to the Arduino. Probably I haven't looked around hard enough.
L.
Me:
>
> Does anybody know about an equivalent of the
> Timer1 library for the Sanguino?
Traumflug:
>
> Hmm. What's the Timer1 library, what's wrong with
> it and to where do you want to port it?
Timer1 library for arduino (atmega168, atmega328) http://www.arduino.cc/playground/Code/Timer1 , provides an unobtrusive interface to manipulate, well, timer 1 (arduino pins 9 and 10) settings, such as PWM cycle, attach interrupts etc.
I am currently testing stuff with an arduino. I was looking for something to modify the default PWM cycle setting for Timer1 (about 500 Hz) to about 32 KHz. This will come useful when pwm-driving a small spindle DC motor with the mentioned MOSFETS, and as implemented in the library, is a fire-and-forget operation.
#include "TimerOne.h"
const int ledPin = 10; // LED connected to digital pin 10
const int potPin = 5; // Potentiometer connected to analog pin 5
int potval = 0 ; // store value of pot here
void setup() {
Serial.begin(9600); // init serial comm
Timer1.initialize(30); // initialize timer1, and set period to 30 microseconds
Timer1.pwm(ledPin,0) ; // initialize PWM on pin 10 with duty cycle 0
}
void loop() {
int potval = analogRead(potPin); // read pot
Serial.println(potval) ;
Timer1.setPwmDuty(ledPin, potval) ;
// wait for x milliseconds
delay(10);
}
I agree this does not make any sense if you just want to drive a couple of heater resistors, but should you ever want to do some light milling with Gen7 electronics and some sturdy reprap design, you'd find uses to higher PWM frequencies.
Yes this can also be done by directly and-ing / or-ing some registers, but in a more involved way (IMHO).
So I went looking for more information on Sanguino / atmega644 pins ports and timers, but of course there is less documentation floating around, as compared to the Arduino. Probably I haven't looked around hard enough.
L.
Sorry, only registered users may post in this forum.