using shield with stock R3
My gerbil arduino board burned out. I was hoping to be able to use a stock Arduino right now so I can get my laser up and running again. How do I go about doing that?
Hi, you can indeed use the K40 shield with a standard UNO R3. The only thing you need to set is the PWM output port. In the standard Uno, they use D11 which corresponds with Jumper Timer2 on the shield. Only one jumper for the PWM should be bridged. So leave the two other jumpers Timer3 and 4 open.
Also be aware that the standard Uno has only 8 bits pwm which means 255 values over the full power range. Which leaves you with just 3 or 4 shades of grey in the 2mA region.
So if I may ask, what happened to the board? Anything I can do to help?
cheers, Paul
Hi Paul!
I am going to use K40 shield with (old)arduino uno R3 .
My power supply is one of the OLD style
Do you think I will have a pwm laser supported?
Thank you for your time,
Alex
Uploaded files:
Hi Alex, yes you can use the legacy K40 shield with a standard R3 Uno. However you need to set the PWM jumper on the shield to Timer2 (Arduino port D11). The other jumpers Timer3 and 4 need to be open since R3 does not have these ports (used on the R4 controller board).
Also note that the pwm on the R3 is just 255 levels. Engraving is not going to be well unless you use just B/W. Cutting however seems to be work well with 255 levels (8 bits resolution).
Hi Alex, yes it should work, just follow the potmeter middle lead to the PSU board which is the PWM input. Disconnect that wire and connect the arduino pwm output to it. There is a little label (silkscreen) on the shield ('PWM to laser psu').
Hi alex, that hex file is written specific for the R4 which uses a different processor than the R3. You need to load the R3 code from github.com
Also you need to set the serial communication jumpers back in the position for the R3. The silk screen probably says something like uart 0.
Also bridge the jumper for timer2 for the pwm.
Cheers Paul
Paul thank you my friend you are so informative and helping me out!
I imagined so about the difference between R3 vs R4 (pb version) but I cannot locate the code for R3
Doy you mean the generic code of GRBL?
https://github.com/gnea/grbl/releases
????
Yes the gnea is the generic code for R3.
Hope this helps
Cheers Paul
Success (at last!) Now I have communication with my sheild & R3.
One small question-though : Giving $$ I noticed every parameter is there except $28 (pwm) maybe this is due to fw 1.1f does not support this feature?
Yes a lot of customisation went into the R4 firmware. Sorry you might need to play around a bit with the gnea code to change the pwm frequency .
ok I see.. Thank you very much Paul for your quick responses . Have a nice.... evening (!?)
(Here in Europe is morning actually!)
Hi Paul,
It looks like I had a similar problem to the original poster here. My gerbil Arduino board suddenly stopped responding via usb. No visible issues, nothing I tried brought it back. This was about 1 year after first operation.
I installed a stock Arduino, but I believe the larger USB port case ended up shorting out one of the end stops which has pins on the Gerbil board above it 🙁
Any ideas on how to fix the Gerbil Arduino board?
Any suggestions on end stop replacement? I'm working from this page: http://donsthings.blogspot.com/2016/06/k40-optical-endstops.html
Hi Arnold, the firmware is written for a different processor (328PB) than the Arduino Uno (328P). The 328PB has two uarts instead of one and this is remapped on the shield to free up the 16 bits PWM port. So you need to re-flash it with the hex file from our downloads page or here https://github.com/paulusjacobus/awesome.tech