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A few Friday’s ago I was enjoying some adult beverages and playing around with some humidity sensors.  I decided it would be cool to expand beyond just measuring humidity and temperature by adding some air quality sensors to the project.  So I dug around on the internet to see what kind of cheap sensors were out there.

After a bit of digging around on the interwebs I ended up on Aliexpress and started adding some sensors to the shopping cart.  I am normally fairly frugal and try to justify most of my expenses, even on hobby projects.  But with the lowered inhibitions thanks to the beer I let myself go a little overboard with the order.  While adding items to the cart, I noticed that the shipping costs added for each part was rather random.  After some further investigation, I stumbled on a neat little trick to keep shipping costs down.  Aliexpress is essentially a portal for sellers and distributors.  From what I could tell, each seller has their own shipping cost rules.  For example, some sellers will add a flat shipping charge for each part, whereas some will discount the shipping costs per part as the order volume increases.  And if you look hard enough, you can find some sellers that charge a flat fee, regardless of the number of parts.  So if you limited your order to only items offered by one or two sellers with the ‘fee per order’ structure (most sellers sell a lot of similar stuff anyways, so it’s not hard to get most of what you need from a single seller), than you can reduce your shipping fees fairly dramatically.  After an hour or two of digging around I queued up an order for a dozen or so sensors and other items for a grand total of ~$40.  Considering how much I can spend at a bar on a typical night out with friends, this was a fairly reasonable total for a Friday night of ‘fun’.

About a month later, the package arrived at my doorstep.  By the time it had arrived (it takes a nice long journey via boat from china) I had forgotten most of what I had ordered, so was eager to check things out.

They packed things in tight.

It’s pretty crazy what you can get from China these days.  For ~$40 I got some CO sensors, Alcohol sensors, soil moisture sensors, some microcontrollers, a camera module, a VOC sensor, and some LiPo charging boards.  This will be enough to keep me busy for awhile and I am excited to put some of these sensors to use!