One step forward, one step back

A project log for Barnabas-Bot

An open-source educational robotics project that inspires elementary and middle school kids to invent through building their own robot

ericeric 11/10/2017 at 20:100 Comments

Hey everyone,

Long time no see guys. I just thought I'd give you an update.

    Since I last checked in there have been a few changes. First being the serial chip that we were using in the prototype, an FTDI chip, was replaced by a ch340ser chip, mostly due to reduced cost. However this lead to a pretty stupid mistake on my part which ended up halting progress for a couple weeks. I had decided to use the 340t version of the chip, but for whatever reason I used the 340g pinout when editing the schematic. Essentially, my schematic includes a part which doesn't exist.

    We have since fixed this in the schematic/PCB and have new boards on the way, but That is not the only change I have made. In addition I have removed the diode that was previously between the external reset pin and the reset pin on the atmega328p. For some reason that diode was making the process of burning the bootloader onto the atmega chip very difficult. My guess is that the voltage drop from the diode was causing the reset to not trigger on the chip, but I could be wrong.

    You can see where the diode was removed in the schematic above.

    I don't want to speak too soon but I've got a good feeling about the new version of the board. Hopefully next time you hear from me I'll be bringing good news.

Till next time,