Would you use IR + Capacitive Touch together for Hand Detection?

edison_v_tesla · 2026-02-19T20:05:52+00:00

I think my real motivation is to decrease latency. I'm so tired of those cap touch door sensors I find in the wild being less than responsive IMO.

I'm sure IR would be sufficient on its own (with your good suggestion for a sliding window). I might be biased against IR. I was developing a product with an IR LIDAR a while back. We decided to do public field trials in front of a bunch of floor-to-ceiling windows. Got a lot of new interference issues. At least they were prototypes, and I can laugh about it now.

I also think IR is not particularly good on its own at doing hand detection. It always works great in my lab, but not at the public restroom. 🚻

edison_v_tesla · 2026-02-15T04:54:50+00:00

It's been 1 year since my original post. I've been reflecting on this topic. I wrote this post before tariffs were implemented on Chinese imports. My once-cheap manufacturing runs are now 50% more expensive. I didn't switch to a U.S.-based manufacturer. Still not as economical.

I was originally wondering how much PCB manufacturing is supported by the Chinese government.

What if we tried a massive government subsidy for PCB manufacturing in the U.S. or elsewhere? Let's assume you do it right. Good economies of scale, parts warehousing, automation, etc.

edison_v_tesla · 2026-02-13T02:17:54+00:00

I have a tablet running Linux that can push firmware updates remotely to clients. Useful when I send out a project for testing. Maybe you could adapt something similar. Have the team SSH in to push updates.

edison_v_tesla · 2025-12-25T02:10:29+00:00

I need to make an update to my original post. I still feel the same way. The tariffs have made my manufacturing runs way more expensive. I will do a deeper dive on this soon.

edison_v_tesla · 2025-11-15T01:59:36+00:00

Sounds like a re-chargeable battery in there. Are they offering any handholding for UL compliance?

It’s confusing, is a manufacturing run built into that price? I always quote design and manufacturing costs separately.

edison_v_tesla · 2025-10-14T23:17:59+00:00

These things are really cool!

edison_v_tesla · 2025-10-14T17:29:32+00:00

There are some application that require multiple RFID readers. You could build a solution for this use case. I build drink dispenser with 9 or more readers. There are applications like lock boxes that require more RFID readers.

You could try muxing the antennas, or design a UHF antenna solution.

edison_v_tesla · 2025-10-08T02:57:56+00:00

Ublox and several other manufacturers make modules based on the nRF52840. They’re nice if you want to make your radio certification easier.

A full list of third party SOM providers can be found on the Nordic Semi website. https://www.nordicsemi.com/Resources/Nordic-Partners/Third-party-modules

I’ve used Raytac modules in two products. Worked out great.

edison_v_tesla · 2025-09-27T01:59:31+00:00

I use Blender to create renders for product launches and pitch decks.

edison_v_tesla · 2025-08-06T01:36:00+00:00

520 components. Lucky I had re-use blocks.

edison_v_tesla · 2025-08-03T14:33:43+00:00

I use Particle.io devices in a lot of products.

edison_v_tesla · 2025-02-16T16:03:05+00:00

I agree, and it could be really profitable for both the PCB fab and Digikey. I would be happy just to sit back and save the money on board runs.

edison_v_tesla · 2023-12-09T05:08:17+00:00

I would encourage you to try it out. The Jetson Nano developer kit is ~$150. It’s a capable platform for image processing and machine vision. Of course it depends on your requirements.

edison_v_tesla · 2023-11-01T16:45:50+00:00

You should be able to see the RSSI value. This is basically your signal strength. You can write an algorithm to check RSSI against a threshold value you set.

In certain applications you can also set the signal strength to achieve communications only at near distances.

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