By Sam Holland, product design engineer and co-founder of the informal hardware collective
Why this crossed our desks: As both the father of a nearly 3-year-old and a gadget nerd, I was quick to purchase a Yoto Mini when I first heard of it. The Yoto player works by you inserting cards into the top of the device, which prompts the speaker to begin playing audio related to that card. It’s got a cute design and is easy for my son to use himself — buying us precious moments of downtime. We have PAW Patrol stories, Laurie Berkner playlists, mini games, and many more. I love the use of physical cards as a way to switch between digital content; it’s very playful and tactile.
Naturally, I had to take it apart to fulfill my incurable huger for learning how things work. I didn’t want to risk breaking my device during a teardown, though, so Lindsey very generously accidentally backed over her device with a car and sent it to me.
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The Yoto Mini is intentionally simple. It’s roughly 3 x 3 x 1.5” and has a nice matte texture to the plastic housings. The two-tone housings are neat, and I love the orange pop of color for the knobs.
The front of the device features two knobs you can press in like buttons (1), a speaker grille (2), and a small screen (3). The graphics on the screen are blocky and low resolution, and I initially though it could be made of discrete LED pixels, but further squinting at it convinced me it was just a regular LCD screen with cute artwork. ****
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On top of the Yoto is the slot for the Yoto Cards (4), which only drop in about halfway. They’re secure enough to not fall out on their own, but a toddler can easily pull them out too, providing a perfect balance of security and usability. A very generous beveled entrance makes it easy to insert a card. A lanyard loop sits on the back left edge as well (5).
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The right side of the player features a rubber-coated button that doubles as play/pause and power (6). It’s probably the worst part of the device because it feels unintuitive to use a power button to start and stop audio, as well as turn off the device, and it feels far less satisfying to use than the knobs.
A USB type-C port (7) sits beneath the button and is used only for recharging the device. I’m not a designer, but I found the placement of the button and USB-C port to be a bit haphazard and not well designed. Making them centered would look better to me, but I’m sure there’s a reason!
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The left side of the player features a headphone jack (8) and nothing else.
The bottom of the device is where all of the legal, compliance, and certification information is printed (9). It’s not the prettiest, but it’s the necessary evil of designing consumer electronics.
Two rubber feet (10) are adhered into pockets in the bottom of the housing and provide some grip on a table. Having spied no visible screws during the review of the device, my first guess is that the rubber feet hide screws. This is common practice and I love doing this to provide a clean external surface but make assembly and disassembly fairly simple.
My take:
The split line between the front and rear housing is an interesting choice, and probably made some mechanical engineer frustrated. A three-piece housing design would’ve simplified some of the design-for-manufacturing work, but it wouldn’t look as cool. It’s a tradeoff!
For some reason, the rubber feet are arc-shaped instead of straight lines. It feels wrong to me. Maybe I’m not cool enough to understand it, but I think Yoto may be doing too much here. A simple pill-shaped rubber foot would’ve made more sense to me. Again, I’m no designer, so I could be off here!
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I hate to say “I told you so,” but underneath the rubber feet are two screws (1). Feels good to be right sometimes.
Unscrewing these two Phillips head screws allow the front and rear housings to open slightly, but there were some clips preventing me from getting any deeper. Using an iFixit pry tool, I was able to coax the clips open without any damage, allowing me to open up the housings.
Inside, we’re greeted by a sandwich of a battery (2), a midframe (3), and the circuit board (4), all fastened to the front housing.
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The rear housing has some foam tape preventing dust ingress, and removing the foam reveals a small plastic cover that is press-fit to help create the back wall of the lanyard loop (5).
Snap hooks line the perimeter of the housing (6), and the two thread-forming screw bosses populate the bottom edge (7). A mold ID code and material callout (8) are also hidden inside, confirming that it’s indeed made of ABS plastic.
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Injection-molded plastic parts can get super complex, but if you know what to look for, you can quickly reverse-engineer how they were molded. On the rear housing, I was able to trace out the small parting lines that are the side effect of adding lifters to the mold. Also note the gate on the left side of the housing, where plastic is injected into the part (1). Neat!
Lifters are a magical solution to solving one of the largest issues with Injection molding part design, known as undercuts. Check out this video for a super simple explanation of why undercuts are an issue.
Most high-volume consumer electronics products leverage lifters to achieve fancy fastening features like snap hooks and screw bosses without compromising the appearance of the product.
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Lifters are separate components of the mold that can slide in different directions at different times of the molding process to allow for complex features like undercuts to be formed without causing issues. When the mold is closed (1), the lifter forms an undercut in the mold. The cavity can open without any issues (2) because there are no undercuts there. During the ejection of the part from the mold, the lifter slides out of the way, allowing the undercut to clear the mold (3).
Lifters: Learn them, leverage them, and love them.
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Turning my attention to the front housing, I spy the battery! A bit of foam tape (1) is adhered on top of the battery to help prevent any ratting or movement if the Yoto is dropped (or run over by a car). Peeling back the foam tells me this is a 4.2V 2000mAh 7.4Wh 694449 LiPo battery. It’s double-stick-taped to the midframe, which is very common.
Removing two screws on either side of the midframe (2) allows me to carefully pull it away from the main PCBA, and then break the NFC connector off the board (3) almost immediately after — oops. While we’re looking at the board, check out that cute little screw icon (4).
The midframe does a few things for us. First, it holds the battery in place, and we appreciate that. Second, it forms the slot for the Yoto cards to enter, and has small nubs that provide the holding force needed to keep the cards in place. Lastly, it’s where the NFC antenna is adhered, which is used to read which Yoto card is installed.
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