A few weeks ago, I discussed how to calibrate middle to low end DMMs using a precision voltage reference such as REF01. Of course, you can perform similar calibrations using a precision current reference as well. And in many cases…
After I completed the filament driver and the circuit to drive the multiplexed VFD segments, it is time to finish the VFD clock project I had in mind earlier.
In my previous post, I showed a simple vacuum fluorescent display filament driver built using a 555 timer and a custom hand-wound, center-tapped toroidal pulse transformer. And as promised in my earlier comment, I am going to show you the…
I recently salvaged a vacuum fluorescent display (VFD) from a piece of old test gear. The VFD is a 13 digit 7-segment multiplexed display and I thought it would look great in a custom digital clock or something similar. While…
Having a decent digital multimeters is an absolute necessity if you are doing any types of electronics work (see Dave’s DMM Buying Guide). Those cheap sub-$10 multimeters are usually too inaccurate to be trust-worthy for any kind of serious measurements.…
Avalanche transistors can be used to generate fast rise time pulses. Their usage in the hobby world was made popular following an application note (AN72) by Jim Williams and was further publicized via this EEVBlog video. Many people have built…
I wrote a tutorial a while ago on how to hand solder fine pitched LGA/QFN chips using perfboards. While The technique illustrated works well with low pin count chips, for many people it is still a rather daunting task to…
My seven year old 24 inch LCD monitor (Westinghouse L2410NM) started to flicker recently, so I decided to take a look inside to see what was wrong. Even before I opened it up, I had a pretty good idea of…
I bought an old Tektronix 2445 150 Mhz oscilloscope on eBay the other day. It was listed under “For Parts/Not Working” condition. Since the pictures in the auction listing suggested that the scope powers up and shows traces on all…
I did a teardown of a BK Precision 4011 5MHz function generator a few weeks ago. Like most of basic function generators in old days, BK 4011 does not offer frequency sweep as an option. What it does include is…
The current sourcing/sinking capability of the I/O pins on Raspberry Pi is quite limited. According to the Wiki page, the current limit for each I/O block (e.g. GPIO0 through GPIO27 combined) comes at only 26 mA maximum, which is only…
I got a used BK Precision 4011 5MHz function generator recently. The 4011 model is rather old and this particular unit was manufactured back in 1996. But BK precision still makes a similar model (4011A) which is identical to the…
Neal from SchmartBoard sent me an MSP430F5172 development board to check out. This board, according to the website, was co-designed with the University of Colorado for itw educational needs. It is actually just a breakout board for TI’s MSP430F5172 mixed…
Last week, I discussed the construction of a network-capable temperature and humidity sensor using SHT21 and ENC28J60 with an ATmega328P microcontroller. In this post, I will show the results obtained so far and the techniques used to chart the data.
I did a project on temperature/humidity logging a couple of years ago. In that project I logged the temperature and humidity readings in my basement lab over the course of a year. One issue with the approach I took back…