The Tech Blog

Earlier this week, during a few discussions, I came across the concept of digital vaccines. I had never looked into it before, and the name sounded strange enough that I wanted to understand what was actually happening. It’s interesting enough to be worthy of a discussion today.

The project comes from CMU and FriendsLearn. Despite the name, this is not a biological vaccine. It is closer to a gamified digital therapeutic that tries to train healthier behaviour in children through repeated choices, rewards and implicit learning.

In one randomized trial, 104 children aged 10-11, played a game called Fooya. After two 20-minute sessions, they chose an average of 2.48 healthy food items versus 1.10 in the control group. A later 240-child school trial in Tamil Nadu tested nutrition, physical activity and hygiene. Early analysis found a 0.58-point improvement in infectious-disease prevention knowledge, with stronger effects in younger children.

AI alignment is interesting here. The game records how each child plays and what kinds of rewards influence their decisions. In principle, it can adapt the intervention to that child. Social-media algorithms already learn what keeps you hooked on their platforms. This explores a similar feedback loop with a different objective: reinforcing healthier decisions rather than maximizing watch time.

I do think the name “digital vaccine” is bit of a stretch. It is a clever marketing name, but today the strongest evidence is around learning and short-term behaviour change. Preventing diabetes, obesity or infectious disease is a much larger claim that still needs long-term clinical evidence. A current Type 1 diabetes trial is taking the next step by measuring HbA1c and CGM outcomes.

The bigger question is the engagement part. If children keep using an adaptive health game long enough for the learning to transfer into daily life, this could become a scalable form of preventive healthcare. If the novelty wears off quickly, it remains a good experiment in gamified education. Good that they are trying to put it to good use.

Memory LCDs have been around for a while. It came into my radar only recently. I thought it deserved an dedicated explainer. It sits right in the middle of a TFT LCD and e-paper. Let’s discuss that today.

A Memory-in-Pixel LCD is still an LCD, but each pixel contains a small memory circuit. In Sharp’s panels, its 1 bit/pixel. Once written, unchanged pixels do not need the same image streamed continuously. The panel is reflective too, so daylight replaces the backlight used by most TFTs.

Its really power efficient. Sharp’s 1.28-inch, 128 × 128 LS013B7DH03 specifies about 1µW typical while holding an unchanged image and 50µW when updating the full screen once per second. A similar 1.3-inch TFT module can use around 90mW just for its backlight. E-paper can approach zero between updates, but a typical 1.54-inch B/W panel uses about 26.4mW while refreshing and takes around 2s for a full refresh. Hence it kinda sits in middle.

You also get excellent sunlight readability like e-paper, but much faster response for changing numbers, menus, graphs and simple animation. Indoors it is less vivid than a backlit TFT, and panels are usually monochrome or some limited-colour.

The interface works well with small MCUs. A 128×128 monochrome frame buffer is only 2kB. Sharp’s panel uses a simple 3-wire serial interface, and you can rewrite only the lines that changed instead of pushing the entire frame.

There is one important difference from e-paper. The LCD still needs a tiny amount of power and periodic VCOM polarity inversion, so it cannot retain the image indefinitely after power is removed.

I think its sweet spot is an always-on battery device where the screen changes often, such as watches, meters and outdoor instruments. If the image changes once an hour, e-paper is hard to beat. If it changes every second and battery life matters, Memory LCD becomes very interesting. Cost remains a constraint. These panels are generally above commodity TFTs and closer to small e-paper modules. Do check them out for your future requirements.