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• Loono, the rebirth, part 2

  Sebastien • 06/19/2017 at 07:16 • 0 comments

  For this second part, we will focus on the embedded electronics. As a start, let’s recap the functions that will be implemented.
  

  • Each half-bean should be able to interact with the user. That means detecting if the user is holding the shell, detecting if one half is mated with another half (and if it is the good one or a bad one) and answering in consequence through various vibration (variation of frequency, strength, duration, or altogether – think of a soothing, relaxing vibration for a match and a more angry one for a mismatch).
  • Each half-bean is energetically independent and should be equipped with a battery. In the first part, it was mentioned that the shells should be perfectly sealed, and no hole, contact or protrusion should be visible. Therefore, “wireless” charging should be implemented.
  • Finally, it could be interesting to implement some kind of logging in order to monitor the activity of the user (how successful the game was, how quick the child solved the game, after how many trials, etc.). This would allow monitoring by the parents or educators, whilst also allowing fine adjustment of the various parameters (difficulty of the game, strength or frequency of the vibrations, etc.) to adapt to the disability and sensitivity of each and every one. Since the shells will be sealed once and for all during manufacturing, this communication between the half-beans and the user as to be done wirelessly (Bluetooth, Wi-Fi or other). As a side note, this could also allow remote firmware upgrading if needed.

  Vibration

  The very basic functionality of vibrating is pretty easy to realize in itself. Vibration motors are available is many shapes and sizes, thanks to the cellphone industry. A special attention has to be paid in driving the motors in order to reduce consumption as much as possible, since the battery in each shell will most likely be pretty small. We definitely do not want to be charging the shells twice mid-game.

  State detection

  Detecting the user’s grasp is already more complicated. In the first prototype, this was done using and IR LED and receiver side by side. Although this worked, this solution requires a hole in the shell, which is undesired. Also, it detects when you put the shell upside down on a table, which is also undesired.

  So, we need to detect touch through a 2 or 3 mm wood shell, but also be able to distinguish between the user’s grasp and the shell simply resting on a table or sitting in its charging pad.

  One example of such problem if cooking plates controls. They use capacitive sensors placed beneath the glass surface, allowing detection of user’s touch above the glass surface. There is also some kind of algorithm that detects if a finger is touching one button, or if a pan or a wet rag is touching several buttons.

  If the inner side of the shell was equipped with an array of capacitive sensors, there could be a way to detect (with a slightly more complex algorithm than the one of cooking plates) the state of the shell. If the user is holding the shell with a full hand grasp, several sensors on both sides of the shell would be activated, or only small, isolated activations if the user is holding the shell with a pinching grasp. If the shell is resting on the table, only a small area would be activated. Last, if the shell is in the charging pad, only one half of its surface would be activated. Or something like that. This obviously needs some more thinking, and a lot more calibration afterwards.

  Energy
  

  As the shells are independent and sealed, they need their own inner power supply. This achieved with a small rechargeable battery. In the first prototype, two non-rechargeable CR2032 batteries were doing the job, but this obviously won’t cut it once the product is sealed. The size available in a half-shell severely limits the size of the battery. According to early quick researches and what currently exists on the market, the battery could not be bigger than 500-600mAh @ 3.7V. Also, “Safety...

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• Loono, the rebirth, part 1

  Sebastien • 06/07/2017 at 14:09 • 0 comments

  It has been a while since the first entry (life happens), but it only meant gaining momentum in order to jump further!

  The initial description stated that some prototypes have already been built. But since this is a work in progress, several improvements need to be done before the product reaches its completion.

  Therefore, let's start by listing what has been done, what is good in that and what needs to be improved or even rebuilt from scratch.

  For this first log, we will focus on the mechanical parts (the enclosure).

  Enclosure
  

  A distinctive sign of Loono is its classy shell. A wooden, smooth, natural shell that consists in two parts satisfyingly mating. Hours of research and drawing have gone through this design, and it sure delivers. The shape is enjoyable to hold and play with, even for non-blind people. Thus, this should remain as is.

  However, there are several details that are less satisfying and require improvement.

  First, Loono will be handled by people with disabilities, who might not be fully aware of their environment. The shell needs to be completely shockproof so it doesn't crack when falling on the ground or even accidentally smashed on a table.

  Second, the shell should be completely sealed. Smooth, no holes, no protrusion, no electrical contacts. Remember, users will very likely not see the object and will discover it by touching with their hands or their skin. We do not want to risk any injuries that would ruin the experience.

  Third, the shell hosts the electronics inside. We will go in details about what it hosts later, but the inner surfaces of the shell will need a specific redesign to adapt to the upcoming changes.

  Finally, design for manufacturing. Prototyping CNCed wooden shells was rather expensive. Since Loono consists in several pairs of shells (at least 4, maybe more), each one should only cost a few $/€ to manufacture. When redesigning the shells, special care need to be taken to facilitate manufacturing (few operations, minimum loss of material, etc).

  Pad
  

  For blind people, it is essential that things are always well in place, so they can find it with ease. Loono is no exception to that , and therefore requires a pad to put the stones aside when not using them. A pad already exists, but there is one problem.

  Spoiler alert on Part 2: Each stone will be equipped with a battery, with no external port to the outside world. Does that sound like inductive charging? Yes it does. In order to implement inductive charging, the emitter and receiver coils need to be placed specifically. The pad, as it exists now, might not be suitable for that, and will likely need a redesign.

  This is all for the mechanical part. Part 2 will deal with electronics and will not be as short as Part 1, so stay tuned and expect more! Comments, opinions and tips are more than welcome!

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