A breadboard with an Arduino Nano and various other components documented in the project write up.
Recent Project: The Minimum Viable Voltmeter
This design has an isolated differential input and outputs a single-ended valve to your development board. The GUI is via computer or Android app.
Project write up: www.oihdesigns.com/the-minimum-...
A breadboard populated with an Arduino and various modules has four different voltage rails coming in off a power supply.
Prototyping a process controller. I have accomplished using all four outputs on a recently purchased very nice power supply. I think this justifies the cost…
This is a great idea. Fewer wires for quick prototype tests, and (I assume) no ground loops to avoid.
If you don’t find one LensRentals is great for equipment you want to test before you buy (they will often give a discount on buying the exact piece of equipment you rented).
Nope, I just drew a trace wrong in the schematic, and putting a resistor under the transistor pin corrects the error...
PCB where I have to stick a resistor under a MOSFET because I made a mistake.
No mistakes. Just “happy little accidents.”
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
