Welcome! Log In Create A New Profile

Advanced

Assemble Sanguinololu with no on-board USB?

Posted by frontier204 
Assemble Sanguinololu with no on-board USB?
September 24, 2013 09:18PM
Hi all, (See below for backstory)

Does anyone know what is needed to modify a Sanguinololu to have no USB port? I plan to buy the bare PCB and assemble it without a USB header and any USB-UART stuff between it and the ATMEGA.

I plan to operate my printer with a BlueSMiRF (Bluetooth to UART), and for uploading firmware / testing I have a Pololu AVR programmer and a nice collection of USB to UARTs. Since I have all that stuff already, I don't want to both waste money and risk something getting disrupted by the FT232 that I won't use while printing.

From what I see in the schematic, I have to do the following:
- Omit (do not install) the USB, the FT232RL, and its capacitors
- Run a jumper wire from JP26's #DTR to the other end of C7 to preserve auto-reset
-- I'll check with a continuity tester if this connection is already there. The schematic is a bit unclear if the FT232's #DTR is electrically connected to the external #DTR
- Attach my external UART to JP26 (GND, TX, RX, and DTR)

Are there any subtleties I'm missing to make a Sanguinololu without a USB header?

Thanks!

EDIT: I plan to get this PCB, which looks like a version 1.3 [norcalreprap.com]

----------------------------------------

Backstory: The screw terminal attaching my (poorly made) RAMPS 1.4 burned, so right now I have my heat bed and extruder heater wires directly soldered to what's left of the pads with only a few strips of Kapton tape preventing it from shorting out. I also don't trust my Arduino Mega clone as I noticed its voltage regulator was not the same as the reference. Might as well try out another electronics board and pick out all the stuff myself!

Edited 1 time(s). Last edit at 09/24/2013 09:21PM by frontier204.
Re: Assemble Sanguinololu with no on-board USB?
September 25, 2013 05:43AM
Will bluetooth even be viable ? is this not the reason they use WiFi, for the extra bandwidth ?
Re: Assemble Sanguinololu with no on-board USB?
September 25, 2013 08:34AM
If it's just for enabling another serial device, simply don't solder the USB-TTL chip.


Generation 7 Electronics Teacup Firmware RepRap DIY
     
Re: Assemble Sanguinololu with no on-board USB?
September 25, 2013 09:44AM
Thanks for the replies!

@nechaus: It's been done before - for that matter there seems to be a fork off Sprinter for Bluetooth-enabled Sangui boards. (Though I'll be using Repetier for its protocol which uses less bits and has acceleration control.) I assume Bluetooth would be slower than wired, but it's definitely viable for the slow speeds that my printer uses on its UART. I went all the way down to 28.8k baud with a wired TTL and the printer only paused on large round features.
There's definitely no need for the tens of Mbps from Wifi (actually latency is more important than bandwidth), but from my other work with robots, I know motors and PWM are not nice to wireless communication, so I'm using the Class 1 devices as a "brute force" way to get reception:
[bluetoothinsight.blogspot.ca]

@Traumflug: Thanks for confirming - that's what I expected.
Sorry, only registered users may post in this forum.

Click here to login