In my previous post, I designed and 3D printed a high voltage connector for my Bertan 225-20R high voltage power supply. The silicone high voltage wire I ordered had finally arrived so I made a couple of cables using the connectors I printed. A few of my viewers had questioned the suitability of using PLA as printing material in high voltage applications so I decided to measure the dielectric breakdown voltage of PLA and gather some real-world data.
CurrentRanger is a nanoAmp current meter featuring auto-ranging, uni/bi-directional modes, bluetooth data logging options and more.
It is a highly hackable and affordable ultra low-burden-voltage ammeter, appropriate for hobby and professional use where capturing fast current transients and measurement precision are important.
I have been using the OSH Park’s 4 layer process a lot on my own projects. It has FR408 substrate that has better controlled permittivity and lower losses than ordinary FR-4 that other low cost PCB manufacturers use. In my opinion currently it is the best low cost process for making RF PCBs. My previous boards have worked pretty well, but I decided to make a test board that I can use to characterize the process better.
In the above picture is the test board that I made. It has two 50 ohm microstrip lines of different length, one open microstrip line, one microstrip line terminated with 50 ohm resistor and line with 0402 footprint that I populated with a 1 nF capacitor. I’m using this same type of capacitor as a general DC blocking capacitor in my VNA so I’m interested in finding out how it performs at high frequencies.
Thinking about what values I would like to display, I came up with three basic items. A S-meter when in receive, and a power output display when in transmit. In transmit, I would also like to have the capability of measuring VSWR. Thinking about the switching functions required for this I will need one control line that monitors transmit/receive, this can come from the PTT or key line in the transceiver. Then I use a second control line to select either power or VSWR when the T/R line is in transmit. Another control line can do the same for the S-meter or some other display when in receive. Since this is based on a VU meter, I will use that for the secondary function in receive. Now looking at the signal lines I need to measure, they are the AGC line for S-meter, audio signal for VU meter. And in transmit, the forward and reverse power levels will take care of power and a computed VSWR reading.
The clever solution seemed to be clever, at least for a few minutes. Suddenly the light turned off. I thought maybe there was a timeout for the manual button. Annoying, but workable. The lamp remained off for about another 2 minutes when I started to smell that unmistakeable burning plastic odor. Touching the case of the SONOFF identified the culprit immediately.
Great. So I have an AC mains switch that isn’t working, but I do not want to go poking my multimeter into it. What do I do?
Turns out, that SONOFF module was defective. I wanted to debug it, but I did not want to measure anything while connected to AC. Here’s how I used a thermal camera to debug my SONOFF.
This started when one of my raspberry pi projects failed due to voltage drop on the USB power cable that I was using, so I set out with my power supply and DC Load to measure the voltage drop of various cables that I use in my lab
After successfully building the single-phase energy monitor with the ATM90E26 there has been lots of interest in the 3-phase version. Being an open-hardware project, many people have created remixed and derived versions as well. After a while I started receiving requests to assist with the code for ATM90E36, the 3-phase version of the Energy Monitor chip. However I did not have the hardware to test the code, so I put together this basic devkit to access the SPI bus and easily inject voltage and CT signals to take the ATM90E36 through its paces. This is the first board I have designed based purely on user demand rather than to scratch my own itch, since I don’t have 3-phase supply at home.
I just completed building a device capable of measuring temperature to one hundredth of a degree Celsius and pressure to one ten-thousandth of a PSI! This project is centered around an ICstation MS5611 temperature sensor breakout board which was small enough to fit inside of a plastic syringe. The result is a small and inexpensive pressure sensor in a convenient form factor with a twist connector (a Luer-Lok fitting) that can be rapidly attached to existing tubing setups. Although the screw attachment would work well for industrial or scientific applications, I found that the inner connector (the non-threaded plastic nub with 6% taper) made a snug and air-tight connection with my CO2-impermanent aquarium tubing.
He was looking enviously at the squareness comparator that [Tom Lipton] had made when somone on Instagram posted a photo of the comparator they use every day. [Stefan] loved the design and set out to build one of his own. He copied it shamelessly, made a set of drawings, and got to work.
[Stefan]’s videos are always a trove of good machine shop habits and skills. He always shows how being careful, patient, and doing things the right way can result in really astoundingly precise work out of a home machine shop. The workmanship is beautiful and his knack for machining is apparent throughout. We chuckled at one section where he informed the viewer that you could break a tap on the mill when tapping under power if you bottom out. To avoid this he stopped at a distance he felt was safe: 0.5 mm away.
The construction and finishing complete, [Stefan] shows how to use the comparator at the end of the video, viewable after the break.