Where and how do you find the parts needed to build your hardware? Selling Floppy Emu on a small scale has introduced me to the difficulties of managing a supply chain, and I’ve discovered it’s more difficult than it looks. Doing it wrong means higher costs, more risk, and a danger of running out of key parts at the wrong time. Due to my own poor planning, Floppy Emu has been stuck at “out of stock” for far too long, and I can’t even say for certain when it will be back.

Choosing a vendor from whom to buy parts seems like it should be easy: just use a search engine like Octopart to find the vendor with the lowest price. Sadly it’s not that simple. Some guy on eBay may have the lowest price, but how can I know if his parts are good quality, or if they’re recycled, relabeled, or even counterfeit? Is the savings enough to be worth the risk? And then there are “overstock” vendors like Arrow, Avnet, and Verical, who often have very good prices but require minimum orders of 100+ parts. Are they worth it?

Even if it’s clear which vendor is best for a specific part, it becomes less clear when all the parts are considered together. Floppy Emu is built from about 15 different types of parts, and if I ordered each one from a different vendor, the combined shipping costs from all those vendors would kill me. It’s a balancing act, and it’s often necessary to buy a part from a vendor whose price isn’t the best, so I can combine it with other parts in the same order from that vendor.

Mapping all this out is a pain, but at least it only needs to be done once, right? Wrong. The vendor prices are constantly changing, and less commonly the minimum order sizes change as well. So every time I go to order more parts, I have to start the analysis over again.

I struggle the most with determining how many parts to order. Virtually every vendor has a sliding price scale, where the per-part cost decreases as the number of parts ordered goes up. So there’s an incentive to make orders for large numbers of parts to drive down the average cost, but there’s also a risk. If I order 100 ATMEGA1284 microcontrollers, and then interest in Floppy Emu dries up, I could be left with $1000 worth of useless chips sitting on a shelf. But if I order them 10 at a time, I’ll not only be paying more per chip, I’ll also be reordering nearly every week and risking running out of parts if demand temporarily spikes up.

Out of Stock

My current problems are due to Floppy Emu’s LCD display. In mid-January I thought I had two boxes of LCDs remaining, when in reality I only had one. When I discovered the truth, I only had about six LCDs left. I placed an order for more LCDs on January 29, from the same Chinese vendor I’d used in the past. But then Chinese New Year hit, and nothing happened for a week. The package finally shipped on February 6. Meanwhile, I ran out of LCDs on February 8 and put Floppy Emu into “out of stock” status.

My last order from this vendor took 10 days to arrive from China, so I expected the new LCDs to appear around February 16. But that day passed with nothing in my mailbox, nor the next, nor the next. Time ticked by. As I waited, I accumulated enough Floppy Emu back orders so that the new supply of LCDs would already be nearly exhausted by the time it arrived, so I placed a second order for even more LCDs.

When I checked back on the first order, I saw the vendor was now quoting 25 to 30 working days for delivery. What?! That’s like a month and a half! I’m not sure if this was a change in policy, or the 10-day delivery time I had earlier was just an outlier, but they were now giving me an estimated delivery date of March 7-15. Somehow the second LCD order was estimated to arrive earlier, on February 28 to March 6, despite being ordered three weeks after the first LCDs and being shipped by the same method. And there’s no tracking info on either shipment, so there’s nothing to do but wait.