• Inventory and initial thoughts on build

    Lan • 05/05/2024 at 23:32 • 0 comments

    Got distracted by SCALE and waiting for parts on back order.   

    Restarted the project on April 27th with a massive inventory.  Bought a number of storage containers of various sizes, and then reorganized all the parts by sub-assembly, adding a manifest to each box.   This was valuable in preparing the hardware for a team to build it in parallel.  It also made it easier to identify the missing parts that will need to be ordered.   This was a 3-person project, since it would have been tedious and error prone with just one person.

    On May 4th, we had our first build session where we started with the wiring harness.  We learned that working with silicone-insulated wires is a pain and we're better of with PVC-insulated wires.  We learned how to crimp dupont connectors and also how to test them.  

    The road map says it is better to start with the wiring and PCB board, as it's important to have all the electrical parts be functional, as that is less forgiving than the mechanical parts.   Since most of the mechanical assembly instructions involve comments about how to insert the wiring, it does seem like we will need to try to get the wiring done sufficiently that it can be integrated into the build.

    As for mechanical assembly, although we know what the major components are and what they should look like, we need to refer to the Onshape model to see how it's actually put together, including the fasteners.



    Throughout the process, we've been thinking of how this would work with kids and their teachers.   It really depends on how comfortable the teachers and students are with engineering.

    • Break up the parts into subassemblies
    • Break up the students into teams for each part
      • PCB/electrical
      • wiring/testing
      • coding/brain
      • mechanical
        • body
        • rocker bogie
        • drive wheel
    • Ahead of time, identify the additional tools and/or fasteners IKEA or Lego style
    • moar pictures
    • learning opportunities - connect to STEM topics
      • For example - wire length -> increased resistance -> heat

  • Ordering Process

    Secret-Asian-Man • 10/27/2023 at 04:46 • 0 comments

    Starting out:

    The first thing we did was file for 15% discount for goBILDA.

    Next we made a shopping list with check boxes based on the Parts List.

    What I wished I did next was reference the Errata Tracker to see which parts were incorrect.

    We are ordering parts from 7 stores:

    DigiKey was a breeze to place orders. You can upload the .csv to bulk ordering and it will also recommend replacement parts if sold out. Took about 15 minutes to order.

    goBUILDA was the most difficult. Yes it has bulk ordering, but it still requires  manual entry. Took about 3+ hours to add items and verify the correct amount of items.

    For us the following items were out of stock:

    We still need to find replacements for them or sign up for notifications for when they get restocked.

    Side note: Found a really nice DuPont/JST/Molex crimping kit that should cross a good chunk off the shopping list. It can crimp Molex, but doesn't come with Molex crimps.

    Ordering Process Possible Improvements:

    • Wish GitHub parts list had check boxes.
    • Too many shopping carts.
    • Instructions should mention bulk ordering.
    • Have to be extremely cautious about double ordering an item. Double/triple checking prices.
    • Good to make note of running total for each section to help prevent ordering oversights.
    • Need to automate the buying process. https://www.gobilda.com/bulk-order/ 
      • Possibly with codemonkey
    • Was not aware of Errata Tracker for PCB board. Needs to be noted.
    • Raspberry Pi ribbon cable not explicitly specified to be female to female.
    • Part PCA9685 is listed twice in the parts list
    • Most up to date info on Slack, but there is a 90 day limit.
    • In parts list “laser cut parts folder” link is not found.
    • There seems to be some oversimplification when comparing parts list wiring section and the wiring ReadMe. Almost led me to purchase wrong parts.
    • Wiring ReadMe doesn’t list Molex connectors in the “In total:” section.
    • Wiring ReadMe keeps mentioning “Molex connectors”, but I think it means Molex crimps. The PCI-E connector is the one housing the Molex crimps.

    Planning DIY body plate:

    We are planning on cutting the Body Plates ourselves. I downloaded the .dxf files, loaded and dimensioned them onto AutoDesk AutoCAD to get an idea how much 1/8 inch thick acrylic we need to buy. Our laser cutter workspace is 32x18 inches and it looks like we need 4 sheets that are bigger than 10x13 inches.

  • Kickoff

    Lan • 10/20/2023 at 23:12 • 0 comments

    Hurrah, we have officially started SGVHAK Rover 2.0.

    Just like we did 5 years ago, we are going to be building the Open Source Rover. This time, it's with the new, improved, cheaper design that was released recently.   We are looking forward to providing feedback to the project and additional documentation.

    Our first steps was to order the parts.  This requires going through 6 vendors and Amazon. 

    * signing up for a group email address

    * establishing accounts with the vendors using said group email

    * some decision-making about premade vs DIY

    * some decision-making about whether to go with the recommended minimum, or a beefier option.

    We also set up this Hackaday.io project to make it easier to document our work in a collaborative way.

    Pro tip: goBilda, which is the vendor for the majority of the parts, has a Bulk Order page, so you can just enter SKU and quanity.  Which is a lot  easier than visiting each parts page and adding it to the cart.