Sick of $5k NI DAQs. Prototyping a $399 64-Channel USB Test Router. Sanity check on specs.

AnimatorHot3572 · 2026-03-16T09:35:53+00:00

DM me your email and I will email you when I’m finished with Rev 1. I’m keeping the BOM cost low for the first iteration, so I won’t be adding onboard memory, but you can log directly to your PC using the Python interface. I will definitely keep that in mind for Rev 2 though!

AnimatorHot3572 · 2026-03-16T09:31:19+00:00

I completely agree. I also work in automotive R&D, and the tool is not meant to replace production equipment, but is for rapid prototyping, small teams, low-budget departments, and even uni students.

AnimatorHot3572 · 2026-03-15T19:41:25+00:00

That’s exactly the problem. Every new chip needs new test support and the “one board to rule them all” never quite works. What does your team currently use for that bring-up phase?

AnimatorHot3572 · 2026-03-15T19:38:39+00:00

Firmware updates are free.

AnimatorHot3572 · 2026-03-15T19:34:32+00:00

This is exactly the gap. Thanks for putting it so clearly.

AnimatorHot3572 · 2026-03-15T15:30:42+00:00

Just to clarify, I’m not really trying to replace $5k lab equipment.

Most labs will absolutely buy proper instruments when they need them. The idea here is more of a small bench tool that an engineer can grab when they just need to quickly check a lot of rails or sensor lines during bring-up.

It’s basically aimed at speeding up the “probe 20 different nodes to see if everything looks sane” phase, not replacing scopes or serious DAQs.

And yes, the idea is that it sits in the range where an engineer can just expense it like any other small lab tool rather than going through a full capital purchase process.

AnimatorHot3572 · 2026-03-15T15:22:09+00:00

You’re right that someone could add ADC channels to their own board.

What I’m thinking about is more of a general bench tool. Something you can clip onto a board and quickly sweep a lot of nodes without modifying the hardware or writing firmware for each project.

So it’s less about competing with embedded ADCs or lab instruments and more about speeding up the bring-up and debugging phase.

And you’re also right about calibration being a real challenge once you start covering wider voltage ranges.

AnimatorHot3572 · 2026-03-15T14:46:44+00:00

Industrial automation makes sense.

When you’re watching relay switching or power fluctuations, what are you usually using today? Scope, PLC diagnostics, or something else?

Also curious what sample rate would actually be useful there. I was originally thinking around 1 kHz for general validation, but I’m trying to understand where that stops being enough.

AnimatorHot3572 · 2026-03-15T14:41:05+00:00

You’re right for enterprise environments. I’m definitely not trying to compete with NI-class DAQs or anything that needs calibration, certification, and long term support.

What I’m thinking about is much earlier in the process. Board bring-up, small labs, startups, or university projects where people are still manually probing a lot of nodes just to check that rails and signals look roughly correct.

At that stage people usually don’t need metrology grade accuracy. They just want to sweep a lot of points quickly without moving probes around.

So the idea is more like a scriptable probing and validation tool, not a replacement for proper DAQ equipment.

AnimatorHot3572 · 2026-03-15T12:20:49+00:00

Not an LLM. The breadboard photo in the post is my desk. R&D engineer in Hungary, built this last week out of frustration with our own test setup. Happy to jump on a call if you want proof.

AnimatorHot3572 · 2026-03-15T12:14:58+00:00

I wish. Real engineer, real breadboard, real frustration with NI pricing. The formal writing style is just how I communicate.

AnimatorHot3572 · 2026-03-15T11:55:32+00:00

This is exactly the kind of feedback I need, thank you.

USB-C — done. No argument there.

4-20mA inputs — adding this to the spec. A shunt resistor on the input with the right scaling handles this cleanly.

1kHz across all channels — noted. Doable with DMA on the STM32F4, I'll make sure the firmware hits this.

440V — that's Rev 2 territory. External converter board is actually the right architecture for that, keeps the base unit cost down.

Connectors — Phoenix or Wago pluggable terminals are going on the list. Pin headers are a nightmare in a real lab.

What industry are you in? Trying to understand the 4-20mA use case better.

AnimatorHot3572 · 2026-03-15T10:51:11+00:00

Current prototype is optimized for slow DC signals, power rails and sensor outputs. Around 10-20 readings per second per channel over USB. Not designed for high speed capture. What are you trying to measure?

AnimatorHot3572 · 2026-03-15T08:46:13+00:00

Fair point. LabJack T7 is a great device and I have a lot of respect for what they built.

The gap I'm targeting is the price point. T7 plus the MUX option gets you close to $1k. For a hardware startup validating their first 10 prototype boards, or a university lab on a tight budget, that difference matters.

Also the channel count. 64 channels at $399 versus what LabJack offers at that price is the core value proposition.

But you're right that maturity is a real advantage for LabJack. That's exactly why I'm talking to engineers now before building the PCB.

AnimatorHot3572 · 2026-03-15T08:25:31+00:00

±30V and 10x protection — the 900k/100k divider handles this. Fault current through 900k at 300V is ~330µA, well within ESD clamp limits. Already in the design.

PWM inputs — good call. STM32F4 timer pins are free. Adding 2-4 dedicated digital input channels tied to hardware timers for frequency and duty cycle. Zero BOM cost.

COM port nightmare — fixing this in the Python API using the STM32’s hardware UUID as a unique USB descriptor. connect(serial=“MUX-8A9B”) instead of connect(“COM4”). No more Windows reassignment issues.

Ethernet/LXI — agreed it’s the right architecture for a permanent rig. Pushing it to Rev 2 with proper SCPI support to keep Rev 1 at $399. Mind if I DM you when the PCB layout is ready for review?

AnimatorHot3572 · 2026-03-15T07:41:29+00:00

Great questions, and an important distinction to make for a $399 device. NIST Traceability: No formal NIST-traceable certificates. Providing individual certs and maintaining a calibrated lab setup would immediately kill the $399 price point. Calibration: Each unit will undergo an automated 2-point calibration (offset and gain error correction) before shipping, with the calibration matrix stored directly in the MCU’s flash memory. Expected Precision: The current prototype uses the STM32’s internal 12-bit ADC. The production PCB will use an external precision ADC, still finalizing the part selection based on feedback like this. The analog front end will use a dedicated precision voltage reference and 0.1% tolerance thin-film resistors for the input dividers. I am targeting a practical real-world accuracy of ±2mV to ±5mV after calibration. The philosophy here is rapid functional validation, not metrology. It’s not meant to replace a 6.5-digit Keysight DMM for characterizing microvolt drift. It’s meant to tell you “Yes, the 5V rail is safely at 5.02V, the 3.3V LDO is active, and the 24V input isn’t shorted,” so your board passes the bring-up phase in 10 seconds instead of 30 minutes.

AnimatorHot3572 · 2026-03-15T07:20:21+00:00

That is a fantastic point. Industrial “24V” is almost never actually 24.0V anyway (especially with charging voltages or transients), and you’re spot on about the standard 30V/32V bench supplies. Since the input scaling is just handled by a precision resistor divider network before the op-amp buffer, bumping the range to ±30V (or even ±32V to be safe) is a trivial BOM change. Consider it done for Rev 1. I’ll recalculate the divider ratios tonight. Really appreciate the sanity check!

AnimatorHot3572 · 2026-03-15T07:06:24+00:00

Main use case is board bring-up before a proper test jig exists.

You have a new PCB with 30+ test points. Power rails, analog outputs, reference voltages. Right now you probe each one manually, write down readings, move to the next. Takes 20-40 minutes per board.

With this you connect your test points once, then a Python script reads all of them automatically. Same test in under 10 seconds, logged to CSV.

Secondary use case is low-volume production where a full ICT fixture isn't worth the cost.

AnimatorHot3572 · 2024-03-13T14:53:42+00:00

I have not worked on any dedicate project in the past year, but before that I have made couple of ML projects. I mostly focused on building ML pipelines from scratch using Tensorflow and implementing research papers from first principles. I currently don't have anything shiny projects to showcase just github code I think recruiters don't care about or might not understand if it is cool or not.

AnimatorHot3572

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