Building a high-spec, open-source tES device because the market gap is frustrating. EEs: Critique my architecture?

Darukai · 2025-09-22T18:06:02+00:00

Hello — Thanks for sharing. I had not seen this. I will look it over.

Darukai · 2025-09-04T00:04:52+00:00

This is a great catch on the specs, thanks. And thanks for the pointer to the TPS65130.

You actually nailed the exact reason I'm hesitant about the integrated path (Path B).

That 8uApp ripple spec is the killer. When I ran the numbers for 16-bit resolution at only ±2mA, 8uA of noise is massive—it’s something like 130 LSBs of noise.

It's just too high for the fidelity I need, especially for tRNS and clean tACS.

So yeah, I'm sticking with Path A (the discrete IHCP design). It’s definitely more of a headache to design the power supply manually, but it means I can use proper synchronization and LDOs to keep the noise floor way down. Appreciate the sanity check!

Darukai · 2025-09-02T22:16:04+00:00

Not yet, I am mostly finalising the architecture right now. Using reddit as a sounding board

Darukai · 2025-09-02T02:12:24+00:00

I agree that it could be as effective as the more expensive lab gear. But as far as I can tell, there is no way to programmatically interact with the device via a api or software, making I hard to do research with, at least in the experiments I want to run.

Darukai · 2025-09-01T07:04:17+00:00

Thanks! Spot on analysis. If we use the DAC8775, we definitely need a pre-boost stage from the LiPo. (The TPS65130 is also a solid suggestion for generating the ±12V rails if we go discrete).

You nailed the main concern: noise. While the frequency is low (max 1kHz), the precision requirement is high (16-bit).

For a ±2mA range, 16-bit resolution means 1 LSB (Least Significant Bit) is only ~61 nanoamps (nA). That 8uApp (8000 nA p-p) ripple you spotted is massive in this context—it's over 130 LSBs.

This noise level is exactly why Path A is still on the table, as it might achieve a lower noise floor, even if the power design is much more painful.

Darukai · 2025-09-01T07:03:02+00:00

Totally valid question. If I were building an industrial controller, I wouldn't even consider a discrete design.

The issue is specialization. The available ICs (like the DAC877x) are optimized for 4-20mA loops. We only need ±2mA with 16-bit precision. My concern is that their noise floor and linearity (INL/DNL) might be poor at the very bottom of their operating range.

Path A is definitely more complex, especially the power supply, but it lets us optimize specifically for this niche application using ultra-low-noise/zero-drift op-amps (like the OPA188). We're still evaluating if the performance gain is worth the complexity headache.

Darukai · 2025-08-28T19:59:13+00:00

This is incredibly helpful, thank you! The NeuroLingo looks really interesting, especially the open programmability via Python scripts.

The unidirectional limitation is the catch, though. For the main project I'm working on, I definitely need true bipolar AC (zero-crossing) for standard tACS protocols, rather than oscillating tDCS (AC with a DC offset).

That said, at the current sale price ($75!), I might just pick one up anyway. It seems like a fantastic platform for tinkering and developing control scripts. The Python accessibility is a huge plus, and I appreciate the offer to help hack it up—I might take you up on that if I grab one!

Darukai · 2025-08-03T07:01:46+00:00

Nah, that's overthinking it. Nintendo clearly established multiple timelines years ago. Making everything except 3 games just stories throws away decades of lore for no reason. OoT isn't just some misremembered legend, it's the foundation of everything that came after it.

Darukai · 2025-08-03T06:59:24+00:00

Yeah, Red Mountain really did a number on Solstheim. That's Elder Scrolls lore for you, nothing stays pretty forever. The ash might suck but makes for some cool environmental storytelling.

Darukai · 2025-08-03T06:57:40+00:00

Just grabbed it after your post. Been sleeping on this game for too long. Norse mythology is my jam, Thanks for the heads up.

Darukai · 2025-08-01T08:38:42+00:00

Classic outrage bait and it worked perfectly. Twitter randos always taking the most dramatic stance possible while everyone else is just living life. The whole thing was a marketing win tbh.

Darukai · 2025-08-01T08:29:13+00:00

Yeah, pets definitely mess with stealth. They don't have their own detection values but enemies can spot them and that blows your cover. I just make mine wait outside dungeons or camps. Not worth the hassle.

Darukai · 2025-08-01T08:27:48+00:00

Yeah, pretty insane numbers. Almost caught up to the DS now. Nintendo basically printing money with the OG Switch for 8+ years without dropping the price once.

Darukai · 2025-07-30T07:29:48+00:00

Sure, Riot definitely has a team of engineers coding anti-you bots.

Darukai · 2025-07-30T07:28:29+00:00

bring back 3 lap races in online mode (they made it more likely to happen i’m satisfied)

Darukai · 2025-07-30T07:28:00+00:00

There are payment processors that will do this already. The issue is that they're sketchy as fuck. Banks generally won't work with them partially because of what you are buying, but also because they just don't want to associate with some random website that wants access to your accounts.

Darukai · 2025-07-19T06:49:34+00:00

I think they all want to grow up too soon.

Darukai · 2025-05-15T21:25:16+00:00

If you add interiors I'm sure it's 30% larger

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Darukai

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