#robotics Logs

May 20 2018

12:00 AM rue_shop4: FSM
12:53 AM rue_: and now I'v proven out led based FSM roms
12:53 AM rue_: if I can reliably burn out bond wires on 8x8 led matrixes, I'm set
12:54 AM rue_: tho, currently their larger than a 27xxx eprom...
12:54 AM rue_: but not hte 5x7 ones
01:26 AM rue_shop4: well, I suppose that I should get the hexapod moving then
02:01 AM rue_: damn roll of solder is gone wtf
06:36 AM RahulAN: Hi All
06:36 AM RahulAN: I have pi 3 B+ board
06:37 AM RahulAN: and want to interface 4 motors on it do i need extra power?
06:39 AM Hamilton: RahulAN, No experience with PIs but I'm pretty sure you need a driver for those motors (maybe as simple as a MOSFET)
06:42 AM RahulAN: Hamilton, Yes correct ! I have motor driver modules [L293DE]
06:42 AM RahulAN: Hamilton, Do i also need a extra power source ? like this http://www.rhydolabz.com/wiki/?p=11288
06:42 AM Hamilton: RahulAN, What do you mean by *extra power*..just don't expect PI to source VCC of motors
06:43 AM RahulAN: Hamilton, Yes i was expecting same. Thought of give VCC from pin 1 of Rpi
06:44 AM Hamilton: Perhaps PI has a regulator from V_in to Vcc (of the processor)...You should not source motor current form Vcc
06:45 AM RahulAN: Yes correct!
06:45 AM RahulAN: Hamilton, this looks neat http://wiki.seeedstudio.com/Raspberry_Pi_Motor_Driver_Board_v1.0/#hardware-overview
06:46 AM Hamilton: RahulAN, That link you mentioned is strange....It even attached a motor to a breadboard...I though limitation of breadboard connection is 500 mAmps
06:46 AM RahulAN: Hamilton, aah.. Looks like that is not good article ! :D but peaople commented it works
06:49 AM Hamilton: RahulAN, Shields usually do these things right...It seems your second link has separated motors V_in from processors Vcc
06:49 AM RahulAN: Hamilton, Yes .. it have a saparate VCC power source
06:49 AM RahulAN: Hamilton, Do you have any suggestions for 4 motor driver module
06:51 AM Hamilton: RahulAN, You mean a single driver module for 4 similar DC motors? No...check out sparkfun/adafruit...there must be many of these stuff
06:51 AM RahulAN: Hamilton, Sure will check there :) Thanks
06:52 AM RahulAN: Hamilton, can this be possible we can share the powersupply to Pi as well as Motor module from a single power source
06:54 AM Hamilton: RahulAN, I think so...You need a DC-DC convertor to feed the Vcc of processor...and another DC-DC convertor to feed the motors...If motors could tolerate the V_powersuply (like 12V motors) then the second convertor for motors is not needed...
06:55 AM Hamilton: But I guess this circuit introduces noise to the main supply and if the processor's convertor is not good, that may damage processor (or brownouts)
06:56 AM Hamilton: But I'm not an analog expert...ask ##electronics for better solutions
07:00 AM RahulAN: Hamilton, Yes that is aos correct
07:00 AM RahulAN: well i am also not too good at it. I will try finding more ways
07:15 AM z64555: ...and I just got here
08:31 PM * rue_shop4 builds a demo motion file for the fair...
08:31 PM rue_shop4: fer the hexapod!