Nick Mann

Another example video of my DMM that automatically reports open vs closed leads in a voltmeter circuit.

Note that the meter reports continuity when in parallel with the transformer, but then the ~120vac when I flip it on.

(No spoken audio)

I just finished writing a description of it, here: www.oihdesigns.com/mannvoltmete...

(Short answer, I open a MOSFET after a 0 reading to break a bridge and that puts a 2.5vdc through a 500k resistor to one probe, and I check if the other probe sees it.)

Thanks!

I have a long write-up here, which also links to a GitHub where I’ve published my designs: www.oihdesigns.com/arduino-

Video of my DMM showing voltage - floating leads - closed leads measurements.

(No spoken audio.)

#arduino
#electronics

A DMM screen reporting "V Floating" when the leads aren't touching anything.

A DMM screen reporting 9vdc when connected to 9vdc battery.

A DMM screen reporting "V Closed" when the leads are touching each other.

My custom DMM can now report the difference between "0 Volts - they're floating" and "0 Volts - same potential."

Pretty stoked to get this working. Should save a lot of "is it off or am I measuring in the wrong place?" when troubleshooting.

#arduino #electronics

You can get remote control relays for this. I was adding some light switches in my house and using remote controls saved a lot of wire and hassle.

Giga DMM showing a reading of 5.0008vdc off a 5.0000 source (because of the divider this is within 2 steps of the ADC smallest unit). Also a plot showing the actual reported voltage by the ADC is bouncing between 4.996 and 5.003

Normal Version, showing 5.0004vdc off a 5.0000 source.

Giga DMM, rearside

Just got calibrated voltage references for my DMMs. Now I can official know how accurate they are.
I also modded one of my PCBs to work with 3.3vdc boards (level shifting the SDA/SLC lines). Now have an Arduino Giga version, where I can plot the voltage readings.

#Arduino #Electronics

I don’t know why Bluesky hates my photos… *sigh*

Photos that didn't upload correctly before.

Showing the internals

Photo day for my most recent Arduino / XIAO board-based DMMs.

My very detailed write up on how awesome this DMM is: www.oihdesigns.com/arduino-mult...

I have also published my designs on GitHub: github.com/oihdesigns/M...

#electronics #instrumentation

I have a circuit that uses an LM317 to source a constant 20mA signal. I keep researching if there’s a better option, but any circuit that’s more accurate is far more expensive and/or takes up a lot more board space. The LM317 just works obnoxiously well.

The DMM reading a 1 ohm resistor.

The blank PCB.

KiCAD pcb design.

PCB schematic.

Just got the most recent Arduino/ XIAO DMM PCBs. It works! It’s precise! I’m happy!

Unlike previous designs, on this one:
-All the power rail conversions are done on the board instead of 3rd party breakouts.
-Precision voltage references for better accuracy.
-Over volt/current protection.

It’ll probably come down to prosecutorial / police discretion even more than it currently does. It’s not like committing petty crimes is particularly hidden right now (see: driving). Might just be “yeah we have the evidence but who cares?”

I mean, might be the least hassle method of summoning someone to help you up.

1/4w. YOLO.

(In all seriousness, I would probably use 2x the required rating unless I was space constrained. Then I would probably test some from the batch first to see how hot they got.)

Electronics benchtop

Oscilloscope screenshot with a small heartbeat signal.

Trying to build a homemade EKG machine. I see a heartbeat! Yay! Now to try and control the noise…

I made a game called “Oscilloscope.” You use a joystick (smoothed by a cap) to try to match a DAC output. Rounds are one minute and it gets harder as you go.
Nothing fancy but still fun Hoping it will entertain my toddlers / stealth teach my stepson electronics.

A shiny holographic sticker with black thermal printing over it saying you can just make a circuit board and no one will stop you with a circuit board trace print in the background

Playing with my new best $10 thermal label printer friend.

I won a trophy at work for being the most competitive.

A small DMM in a printed housing, about 2x3x1" big

A small DMM in a printed housing, about 2x3x1" big, with a 1 Ohm resistor connected to resistance circuit.

The base circuit board.

Another build, this one uses a charge pump for the higher (~9vdc) rail.

Preparing the photos for an upcoming update to my Arduino (well, now Seeed Studio, but same MCU) super compact and useful DMM guide.

You know. It would maybe be useful if these SMD components had pre-soldered wires on them. Wait. Umm. I am not smart sometimes.

Can’t really say yet (I see lots of noise, but I haven’t set up a shielded connection or stable enough source).

Meme with the 24 bit ADC all fancy while the 16 bit looks plain.

ADS1256 module PCB with lots of supporting components next to a ADS1115 smaller PCB with fewer components.

Experimenting with fancy ADCs.

An electronics breadboard with circuity surrounded by a homemade DMM, a normal DMM, and a handheld scope, showing 20mA running through the circuit.

It works! I'm happy! My emotions are driven by circuits functioning or not in possibly an unhealthy way!

But in this case I've discovered an inexpensive IC (MIC4801) that will drive a constant 20mA (or more, but that's what I need) up to 4.8vdc off a 4.9vdc supply. Useful for instrumentation. :D

Figured out how to dim my lights from the TV. Also toggle them on and off. Pretty stoked.

(No Internet involved, just an Arduino with a relay and a digital potentiometer to control the power supply.)

Arduino Uno sized PCB in a small box, turned on with the display reading 0.

Side view, with connectors through the panel.

Other side view of the box.

New redesigned multimeter PCBs arrived yesterday. The barrel jacks for input, buttons, and screen all mount directly to the board to save space and assembly time.

Soldered it up and it works(!). Yay!

An Arduino DMM reading a battery and connected to an ammeter module.

Two Arduino DMM versions with their PCB between them.

An Arduino DMM (small screen version).

The Arduino DMM with the cover folded away, showing the custom shield.

Most recent Arduino DMM revisions. Works pretty great. Almost done writing updated documentation on how they work.

Mono Lake and Yosemite from the air

Bryce Canyon area, I think, from the air

Shiprock from the air

Escalante area from the air.

Today’s first flight was SAC to DFW. Pretty great geologically. Yosemite, Bryce Canyon / Escalante, and Shiprock, among others. #geology

Sitting at the gate for a flight while maintenance addresses something.

…They just turned the plane off and back on again as part of the troubleshooting process.

Screenshot of run results

Running up a hill selfie.

The view up that hill. It went on for awhile.

Just pretty California running trail.

First official event half marathon* (actually a 0.58 marathon because oops) in the books. I am happy about this. The California hills are as steep as they are pretty. Feel good though.