Dusty
INVENTORY
All of Dusty's parts are ordered. They will show up in different boxes on different days. This page is how we check every part in, catch mistakes early, and never lose a piece.
What inventory is, why it matters, a check-in list for every box, and how to keep it all organized.
Check everything in before Sep 19
1
What is inventory management?
Knowing what you have, how many, and where it is.
Every store, factory, and space program keeps track of its parts. A grocery store knows how many apples are on the shelf. A car factory knows it has enough bolts for tomorrow. NASA counts every tool that goes up to the space station. For Dusty, it comes down to three questions.
What did we order?
The parts list. Every part, how many, and which store it comes from.
What showed up?
Open each box, count what is inside, and match it to the list.
Where is it now?
Every part goes in a labeled bin, so you can find it the day you need it.
2
Why it matters
It is much better to find a problem the day the box comes than on build day.
Boxes come on different days
Dusty’s parts come from about six places: Adafruit, SparkFun, Pololu, Walmart, Amazon, and our own drawers. They will not all show up together. The list is how you know what is still on the way.
Small parts vanish
A cliff sensor is smaller than a postage stamp. A screw is smaller than a grain of rice. If they are not put away the day they arrive, they get lost.
Finding a problem early is cheap
A wrong part found the day the box comes costs a return and a few days. Found on build day, it costs the whole weekend.
The schedule depends on it
Sep 19 is the first build weekend: make Dusty drive. Every drive part has to be here and checked before then.
3
When parts go wrong
Wrong parts and wrong sizes slow down real projects, big and small.
A spacecraft lost over units
In 1999, NASA lost the Mars Climate Orbiter. One team sent numbers in pounds of force. The other team read them as newtons, a metric unit. Nobody caught it, and the spacecraft flew too close to Mars and was destroyed.
Lesson: Always check the units. Is it millimeters or inches? Grams or ounces?
A telescope mirror ground wrong
The Hubble Space Telescope launched in 1990 with a mirror that was the wrong shape by about one fiftieth the width of a hair. A testing tool had been put together with one piece 1.3 mm out of place. Astronauts had to fly up in 1993 to add a fix, like glasses for the telescope.
Lesson: Check your measuring tools too, and check big things with a second, different method.
Dusty: the power bank that did not fit
We picked a USB-C power bank before checking the space. Every bank was at least 90 mm long, and the space was only 62 mm. We caught it in the 3D model, before printing, and turned the bank sideways.
Lesson: Measure the space before picking the part.
Dusty: wheels that look almost the same
Pololu sells a 32 mm wheel and a 60 mm wheel that both fit our motors. The 60 mm wheel makes Dusty go almost twice as fast, which uses up the room it needs to stop before the edge.
Lesson: Measure the part when it arrives. A part can fit and still be wrong.
Dusty: the plug that is not USB-C
The micro:bit uses a micro-USB plug, not USB-C like newer phones. Finding that out on build morning means no way to load the program.
Lesson: Check cables and plugs before build day, not on it.
Real projects: waiting on one part
Big construction and factory projects can sit still for weeks because one small part is late or wrong. Workers, tools and every other part are ready, and nobody can move.
Lesson: Order everything at once, check it in right away, and know your backup store.
The big idea
A mistake gets more expensive the later you find it. On paper, it costs a minute. When the box arrives, it costs a few days. On build day, it costs the weekend. After the robot is finished, it can mean starting a part over.
4
How to check in a box
Same eight steps for every box.
1Open it carefullyUse scissors on the tape, not on the box. Tiny parts hide in the paper and bubble wrap, so do not throw any packing away until everything is found.
2Find the packing slipThe paper that lists what the store put in the box. Some boxes have it inside, some only in the email. It may say a part is coming later in another box.
3CountCount each part against the list below. Two motors means two motors. A 2-pack means two sensors in the bag.
4Check it is the right partRead the name and part number on the bag. Look at the "Check" line on the list: the size, the plug, the number of legs.
5Measure itUse a ruler for anything with a size in the list. Wheels, screws, the power bank. A millimeter matters on a robot this small.
6Look for damageBent pins, cracked plastic, crushed boxes, loose wires. Take a photo of anything broken, with the box, before you do anything else.
7Mark it on the listTap Got it, Missing, Wrong part, or Broken.
8Put it in its binRight away. Each group on the list has a bin name. The electronics stay in their shiny bags until build day.
5
The check-in list
Tap a button for each part as its box is opened.
If a part looks different
We listed the main store for each part. If Dad ordered the backup, the name on the bag will be different. Check it against the backup on the parts list PDF.
0 of 24 checked inNo problems yet
BrainBin: Brain
- × 1micro:bit v2From: Adafruit · Checked in Sep 24Check: Says "v2" on the back. The gold edge along the bottom is clean and not bent.
- × 1SparkFun moto:bit motor boardFrom: SparkFunCheck: Has a long slot the micro:bit slides into and a round barrel jack for power.
- × 1Micro-USB cableFrom: Our drawerCheck: The small flat plug, not USB-C. Plug it into the micro:bit to be sure it fits.
DriveBin: Drive
- × 2N20 gear motorsFrom: Adafruit · Checked in Sep 24Check: Both look the same. The metal shaft has one flat side, shaped like a D.
- × 2Wheels, 32 mm (one pair)From: PololuCheck: Measure across: 32 mm, about 1 1/4 inches. If they are 60 mm, that is the wrong wheel.
- × 2Motor brackets (one pair)From: PololuCheck: A tiny bag of screws and nuts comes with them. Keep that bag.
- × 1Ball casterFrom: PololuCheck: Metal ball plus a bag of thin spacers. Dusty needs every spacer.
SensorsBin: Sensors
- × 2QTR-1A infrared sensors (2-pack)From: PololuCheck: Two tiny boards in the bag. Smaller than a stamp. Count them twice.
- × 1Roller lever microswitch (whisker)From: Adafruit · Checked in Sep 24Check: Three metal legs on the bottom and a little wheel on the end of the lever. It clicks when pressed.
SweeperBin: Sweeper
- × 1130 hobby motorFrom: Adafruit · Checked in Sep 24Check: Silver can about the size of a thumb, with a round shaft.
- × 1Brush on/off switchFrom: Our order · Checked in Sep 20Check: Clicks on and off. Two or three metal legs.
- × 1Pipe cleanersFrom: AmazonCheck: One pack. Plenty for three brush tries.
- × 1Brushes to testFrom: AmazonCheck: The brush material to test against the pipe cleaners.
PowerBin: Power
- × 1Anker 321 power bank (PowerCore 5K)From: WalmartCheck: Model A1112 on the back. One USB-C port and one USB-A port. Measure: about 97 mm long and 22 mm thick.
- × 1USB to barrel jack cableFrom: AdafruitCheck: Big flat USB plug on one end, small round plug on the other. The round plug fits the moto:bit jack.
- × 1In-line barrel jack switchFrom: AdafruitCheck: A short cable with a switch in the middle and round plugs on both ends.
- × 290 degree USB-A adapters (left and right)From: AmazonCheck: One bends left, one bends right. Keep both until you know which one points forward on Dusty.
- × 1USB-C phone chargerFrom: Our drawerCheck: Plug it into the power bank. The little lights should come on.
Body and hardwareBin: Hardware
- × 1PLA filamentFrom: AmazonCheck: Sealed bag with a small moisture packet inside. Keep it sealed until it goes on the printer.
- × 1M2 screws and nutsFrom: Screw kitCheck: Dusty needs 18 screws 8 mm long, 3 that are 6 mm, 2 that are 10 mm, and 6 nuts. Measure a screw from under the head to the tip.
- × 1Small zip tiesFrom: StoreCheck: The short, thin kind. Loose wires get caught in the brush.
- × 1Frost King rubber foam tapeFrom: Home DepotCheck: Stops the power bank from rattling. Sticky side goes on the sleeve, never on the bank.
- × 1Double-sided mounting tapeFrom: StoreCheck: Holds the in-line switch on the deck.
- × 1Hot glue sticksFrom: StoreCheck: Check they fit our glue gun: mini or full size.
Problem list: show this to Dad the same day
Nothing here yet. Anything you mark Missing, Wrong part or Broken shows up in this list.
Your checkmarks are saved on this device only.
6
If something is missing or wrong
Do not panic. There are three spare weekends in the plan for this.
Look again
Search all the packing paper, the bottom of the box, and inside the bags. Small parts are often taped to the slip.
Read the email
Stores often ship in more than one box. The order email or tracking page will say if something is still coming. That is called split shipping or a backorder.
Tell Dad the same day
Stores give a limited number of days to report a problem. Show the problem list and the photos.
Keep the wrong part safe
Leave it in its bag with the packing slip. Most stores want it back before they send the right one.
Use the backup
Every part on the parts list has a backup from a different store. That is why the list has them.
Does it change the design?
If the fix is a different part, a different size, or a different plan, it needs a change order first.
7
Keeping it organized
A place for everything, and everything in its place.
One bin for each group
Brain, Drive, Sensors, Sweeper, Power, Hardware, Printed parts. Write the name on a piece of tape on each one. A shoebox works.
Small bags for tiny parts
Sensors, screws and nuts go in zip bags with a label, inside their bin.
Screws in a cup while building
A muffin tin or egg carton gives each screw size its own cup. Tiny screws and nuts are a choking hazard, so keep them away from little brothers.
Shiny bags stay closed
The silver bags protect circuit boards from static, the tiny shock you get from a doorknob. Open them on build day.
Label printed parts
Printed parts look alike. A pencil mark or a bag with the part name keeps the left sensor arm from being mixed up with the right one.
Keep the spares
Extra screws, the unused USB adapter, leftover pipe cleaners. Put them in a Spares bag. Something always breaks.
Take a picture of the kit
Before build day, lay every part out on the table and take a photo. Engineers call this kitting. It also goes on the display board.
Clean up before you stop
Every build session ends the same way: parts back in bins, screws counted, bins in one spot on the shelf.
End of every build session
- •Every screw is back in its cup or bag
- •Every part is back in its bin
- •The power bank is off (and charging if the next session is soon)
- •Nothing is on the floor
- •The bins are together in one spot
Safety
Screws, nuts and sensors are small enough to swallow. Keep them in closed bags or bins, up high, and count them back in after every session.
8
Words to know
InventoryA list of everything you have, how many, and where it is.
Bill of materials (BOM)The engineer name for the parts list: every part needed to build one thing.
ReceivingChecking in a delivery: counting it, checking it, and putting it away.
Packing slipThe paper in the box that says what the store sent.
Part numberThe code that tells two nearly identical parts apart, like Pololu #1087 for the 32 mm wheels.
BackorderA part the store is out of. It ships later, in its own box.
KittingGathering every part for one job into one place before starting.
SpareAn extra part kept in case one breaks or gets lost.
ToleranceHow far off a size can be and still work. Tiny robots have tiny tolerances.
StaticA small electric shock that can damage a circuit board. That is why boards ship in shiny bags.