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Given Mochi’s massive popularity and irresistible cuteness; I decided to recreate this project.
Project link:
At first, I thought this project was
super easy
—so simple that anyone could nail the recreation.
But that was just the polished version the pros showed you in their videos.
Now, as someone who stumbled through every step; I’m going to list out all the pitfalls of recreating this project, one by one—covering material selection, soldering, and component layout.
Step One: What do I have?When recreating a project, you don’t really need to buy the exact same parts as the original maker—though you will need to stock up if you have nothing on hand.
Here’s what I had in my parts bin: a Seeed XIAO ESP32-C3; a Seeed Grove OLED display.
Step Two: Could it work?This is the make-or-break step—it determines whether you’ll have to replace parts or buy new ones.
How to tell? Check the specifications of your electronic components.This is the make-or-break step—it determines whether you’ll have to replace parts or buy new ones.
Here is the original circuit diagram for the project.
1.My Seeed XIAO ESP32-C3 has a built-in power management module—so I didn’t need to buy a TP4056 charging module.
Then I checked the pins; the original board used GPIO20 and GPIO21.
A quick look at the XIAO schematic showed these GPIOs are available on the board too.
2.Next up, the display. The original screen used SCK/SDA pins, which follow the I2C communication protocol—note that some manufacturers label the clock pin as SCL instead of SCK; the two refer to the same function.
My Grove display also uses I2C, so it was a perfect match.
Here’s a catch, though. I checked the schematic of the original chip; it turns out GPIO20 and GPIO21 aren’t directly mapped to the I2C interface either.
What’s more, the SDA and SCL pins on the XIAO don’t correspond to GPIO20 or GPIO21 at all. But the original developer must have redefined these pins in the code—and it doesn’t affect the functionality anyway.
Putting it all together—it works!
Step Three: Draw the circuit diagram for the XIAO connection.It’s essential to draw up a circuit diagram before you start any wiring.
This is the diagram I came up with.
Simply visit the website and make your settings: The Mochi - Dự Án The Mochi by Huykhong
It allows for quick configuration and setup of the device—no manual coding required.
This tool is a graphical programming interface or configuration utility; it streamlines the development process.It allows for quick configuration and setup of the device—no manual coding required.
It also includes a selection of 3D printing resources for your reference.
Watching others do it in videos looks so satisfying; doing it yourself? That’s when the difficulty spikes to the max.
The compact size of the 3D-printed enclosure means our final build has to be tiny and cute. Unfortunately, this also calls for very short jumper wires—and that ramps up the soldering difficulty a lot.
Below are detailed soldering tips:
- First, cut some short lengths of wire; strip the insulation properly with a wire stripper.
But the ends of the wires we just stripped haven’t been treated yet.
Soldering them directly can lead to some annoying problems:
(1) The wires can wiggle all over the place. You might think you’ve soldered them solidly, but one stray wire could touch an adjacent pad—and cause a short circuit.
(2) Only a few wires will actually bond properly; the rest will come loose with just a light tug.But the ends of the wires we just stripped haven’t been treated yet.Soldering them directly can lead to some annoying problems:(1) The wires can wiggle all over the place. You might think you’ve soldered them solidly, but one stray wire could touch an adjacent pad—and cause a short circuit.
These are all the possible consequences of shoddy soldering!
Can you imagine the frustration? You hook everything up, power it on with a big smile, then nudge it a little—and the screen goes dark. (Sobbing uncontrollably)These are all the possible consequences of shoddy soldering!
2.How to solder jumper wires securely?
This video does a great job explaining it.
To sum it up:
- Apply solder paste to the wires—and tin them! Tin them! This step is critical.
- Add a generous amount of solder to the pads!
Doing this will ensure a solid, reliable joint; the wire itself might break someday, but the solder joint never will.
This is what the wires look like after tinning—make sure each one has a nice, sharp little tip.
Solder the wires to the XIAO first.
(I made a silly mistake with the wire colors here; it doesn’t affect the functionality, though.)
(Remove the Grove terminal before soldering; do it carefully—don’t yank off the pads.
Otherwise, your wallet will take a hit.)(Remove the Grove terminal before soldering; do it carefully—don’t yank off the pads.
The comparison below paints a pretty vivid picture.
On the left, the tweezers were positioned incorrectly; only a small section of the wire made contact with the solder. Joints like this break easily.
On the right, the solder formed a neat little sphere—and that’s a joint that stays rock solid.On the left, the tweezers were positioned incorrectly; only a small section of the wire made contact with the solder. Joints like this break easily.
(Ignore the fact that I wired something wrong again.)
tep Seven: Flashing the FirmwareSimply visit the website to configure the settings: The Mochi - Dự Án The Mochi by Huykhong
Then you’ll get to see Mochi in all its adorable glory!
1.I did a test fit first. I pried open the Grove OLED screen and popped it into the face section of the 3D-printed enclosure. I also tried fitting the battery inside to check the fit. (I hope this description makes sense—unfortunately, I didn’t take enough photos to show it.) Then, I used a hot glue gun to secure any loose parts in place.
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