Flyback diode on sanguinololu heated bed control board. Hey everyone. I started getting uncomfortable with the mosfet and traces running my heat-bed on my Sanguinololu. So I made a small relay board to do the heavy lifting. I have a couple of questions however. I did a good hour long print last night. As expected it clicked on and off during heating. I checked my mosfet at the end of the print and it was cool to the touch, YAY. I've read a bit about others that have made these, and it appears that people are using flyback diodes to protect the sanguinololu. I've had people tell me that all the heating components are protected, and other say, the sanguinololu isn't protected. Does anyone know on the 1.3a rev. or would you advise that I put a flyback diode in the circuit? Is the only real risk the corrosion of my switch contacts (mechanical relay)? If I do put a diode in place, will it cause the heater to stay on longer than necessary? Thanks in advance! -Mike 20140702_223135.jpg mod_embed_images_loadimage('2145e44e5cfbbc8bec4df841a29aedd5', '/forum/thumbcache/1a3/571/9cc/0b8/f18/658/c96/8a6/e0d/408/ec_800x400.png', 'https://lh4.googleusercontent.com/-z74x6pIjL1c/U7ry-tWLomI/AAAAAAAAE74/MhoiCkuXDNI/w426-h568/20140702_223135.jpg', 'https://reprap.org/forum/addon.php?158,module=embed_images,check_scaling=1,url=https%3A%2F%2Flh4.googleusercontent.com%2F-z74x6pIjL1c%2FU7ry-tWLomI%2FAAAAAAAAE74%2FMhoiCkuXDNI%2Fw426-h568%2F20140702_223135.jpg', '', 379653, 800, 400, 'Loading image ...', false); . https://reprap.org/forum/read.php?158,379653,379653#msg-379653 Sat, 08 Aug 2026 12:39:38 -0400 Phorum 5.2.23 https://reprap.org/forum/read.php?158,379653,381524#msg-381524 Re: Flyback diode on sanguinololu heated bed control board. https://reprap.org/forum/read.php?158,379653,381524#msg-381524
I actually added one on the relay coil circuit just for safety. :)

I think I need to spend more time on the WIKI - LOL
The SevenSwitch uses a more pretty design and of course a MOSFET so no click-clack.
I'm going over your build guide now, for education!

Though I do enjoy re-inventing the wheel!

Thanks Again,
-Mike]]> brandxtc Sanguino(lolu) Fri, 11 Jul 2014 13:00:42 -0400 https://reprap.org/forum/read.php?158,379653,379883#msg-379883 Re: Flyback diode on sanguinololu heated bed control board. https://reprap.org/forum/read.php?158,379653,379883#msg-379883
Nice you re-invented the SevenSwitch :)]]> Traumflug Sanguino(lolu) Tue, 08 Jul 2014 07:02:57 -0400 https://reprap.org/forum/read.php?158,379653,379653#msg-379653 Flyback diode on sanguinololu heated bed control board. https://reprap.org/forum/read.php?158,379653,379653#msg-379653
I started getting uncomfortable with the mosfet and traces running my heat-bed on my Sanguinololu. So I made a small relay board to do the heavy lifting.
I have a couple of questions however.
I did a good hour long print last night. As expected it clicked on and off during heating. I checked my mosfet at the end of the print and it was cool to the touch, YAY.

I've read a bit about others that have made these, and it appears that people are using flyback diodes to protect the sanguinololu.

I've had people tell me that all the heating components are protected, and other say, the sanguinololu isn't protected.

Does anyone know on the 1.3a rev. or would you advise that I put a flyback diode in the circuit?

Is the only real risk the corrosion of my switch contacts (mechanical relay)?

If I do put a diode in place, will it cause the heater to stay on longer than necessary?


Thanks in advance!

-Mike




.
]]> brandxtc Sanguino(lolu) Mon, 07 Jul 2014 18:24:54 -0400