Photo credit: Home Depot
This is not a full review of the werewolf prop. You’ll find plenty of customer reviews on these products’ web pages. But overall, as store-bought (not DIY) yard haunt items go, it’s an impressive amount of monster for the price. Though I did make a few small changes…
- Not a fan of the mangy-looking fur, I gave it all a good brushing out. I’m spoiled by luxurious Fabio-esque Van Helsing werewolves.
- Added a tail…actually something I had around from a prior Adafruit project!
- He’s awfully thin and I do plan to plump it up a little, with scraps of upholstery foam, or kitchen garbage bags stuffed with foam packing peanuts…anything lightweight, so the motors won’t struggle…and can pack away after Halloween.
The included power supply was a bit weak, and the motion trigger electronics would lock up whenever the head-oscillating motor kicked in.
Rather than try to explain to tech support, I just ordered a beefier 6V 3A 5.5x2.1mm tip-positive power supply on Amazon for about $7. Werewolf runs fine now.
If you plan to do your own experiments on these products’ eye electronics, do not use the main power supply directly! Use a multimeter to check the voltage and polarity at the plug leading to the eyes. On the werewolf I probed, this was 5V, tip negative. Yours might be different.
Looking up the werewolf’s neck into its skull, we can see the eye electronics are self-contained in two small boxes joined by a flat flex cable. Mounting screws are inserted from the outside, so it seemed necessary to peel back the fur and rubber skin to remove these. Some glue was cut around the perimeter of the eyes, where the skin meets these boxes.
Peeling back the fur also reveals the maker’s mark…Seasonal Visions International, who design pretty much all the big animatronic items at Spirit Halloween and other large retailers.
Eyes removed from the skull, then popped free of their housings.
As it turned out, the the enclosures are snap-fit, so it is possible to access the electronics without all the above disassembly…just remove them from the back, keeping the skull and skin intact.
The eyes are both yellow in person…it’s normal with low-cost TFT screens that the colors shift a bit when viewed off-angle, as is happening here.
The silver Sharpie marks are my own notes, so I can reassemble this later.
Let’s see if we can figure out what’s inside, and what it might cost. Most of these are very rough ballpark guesstimates. And remember that the bill of materials (BOM) cost is just a small fraction of the expense in bringing a retail item to market…engineering, manufacturing, distribution and just keeping a business running all play a role. Focusing on the parts here though, as that can tell us something about how it functions…
First there’s two 1.8" 160x128 pixel TFT color displays…a nice boost from the 128x128 pixels of our earlier eye projects. Possibly ST7735, or something similar…not too important, most small displays function very similarly.
Around $1-2 each in large wholesale quantities…probably the most expensive component of the eye electronics.
One display just has a passive adapter PCB with some connectors, while the other contains all the smarts…
The microcontroller was the hardest part to characterize. An AC19AP1Y201-13C1, which I eventually traced to ZhuHai JieLi “Jerry” Technology.
Couldn’t find more info as it’s not shown in their current lineup…but considering their most recent offerings with Bluetooth or WiFi support are around $1, and if the eyes work the way I think, this is probably a barebones 32-bit MCU at a fraction of that cost.
At least I could find a datasheet for the external flash, an XMC XM25QH16BZ16 — 16 megabits (2 megabytes) with single/dual/quad SPI interface. Couldn’t find a price, but a similar chip from Winbond is about 30 cents.
More interesting here is the red dot. This is a strong hint that all these “LifeEyes” creatures — the werewolf, skeleton and dragon — are using identical hardware, and each just has a different preprogrammed flash chip with that creature’s graphics. Red dot = werewolf. Maybe it corresponds to the red flannel shirt that all werewolves are required to wear.
Remainder of the PCB is connectors and passives. Looks like power regulation at the bottom right, and TFT backlight driving at the top left. A few unpopulated pads that probably weren’t needed in the final design.
I was hoping there might be a couple secret jumper pads to unlock other features (like on the Tiny Arcade retro games), but no such luck here. It has one job.
So we might estimate the total eye electronics BOM being roughly in the $5 ballpark, probably less, which seems sensible…it’s just one small feature of the overall animatronic…competing with motors, a steel frame, growling sounds and molded parts.
At that cost, expect we’ll see blinky eyes incorporated in more modest Halloween decor in the future. Start with the big $200-300 animatronics, but it won’t be surprising when it appears in sub-$50 decorations and even masks…consider that the aforementioned Tiny Arcade units retail for around $20.
Having identified the major pieces now, we’ll take an oscilloscope to it, make some observations and try to guess how it works…