- 2023
- Sep
- 29
Did Espressif fix their RF spurs?
Some time ago, I wrote about my experiences with the ESP8266 line of microcontrollers. Specifically, that they had a giant RF spur at 319.98MHz. This wasn’t an unknown issue, the FCC documentation (had I read it beforehand) clearly called that out. See this post: https://wereboar.com … of-cheap-technology/ for more info on that.
Recently, I picked up this little gadget from a well-known overseas marketer. It works amazingly well, although I suspect this one of having hacked firmware… The MAC it gives to the router clearly identifies it as an Espressif device.
One of the things I immediately noticed, however, was that there isn’t a spur. I was running my devices in a similar manner, they were simply consuming data while being connected to a WiFi interface. I have to wonder if Espressif has fixed that issue, or if the firmware is doing something odd to keep that in check. More investigation is needed here, and perhaps a new look at my old designs is in order.
- 2023
- Sep
- 28
An infrared camera for about $40
Within the last 10 years, low resolution and correspondingly cheap IR sensors have come on to the market. Ranging in size from 8×8 to 32×32 pixels, these devices have shown up in many projects and purchasable items.
This type of IR sensor isn’t a camera per se, but instead is a grid of temperature sensors that a processor assembles into a visible image. You could just as easily have a grid of temperature readings instead of the visible image.
One such series of sensors is the AMG88xx series from Panasonic, and probably other vendors with less recognizable names. Costing around $20 from various sites, this 8×8 sensor is cheap enough for the hobbyist.
They’re available direct from the Chinese assemblers: https://www.aliexpre … 256804493110749.html
However, for not much more you can get one assembled into a small package with a screen: https://www.aliexpre … 255801147595884.html
(These are not suggested purchase links, but examples of item cost. I’ve used Aliexpress quite a bit over the years, you generally get what the listing shows - just be careful and make sure you’ve selected the correct item, as they tend to have multiple items in the same listing and sometimes you don’t pay attention and get the wrong item.)
I purchased one of the fully assembled units, received it the other day, and gave it a try. I received exactly what was shown in the listing, a camera module, a screen and CPU unit, all assembled into a couple of pieces of plastic sheet.
There’s no battery, so you have to plug it in to a USB or other 5V source via the Micro USB on the side. It comes up immediately with the image.
Here’s a hot cup of tea. You can clearly see the hot spot, even if it’s not well defined. The temperature reading is in °C, and there’s no way to change that. Not a big deal.
A glass of cold water from the tap.
And a cold drink that’s set out for a while.
This, like most devices of it’s kind, auto-scales the temperature colors so the hottest spot, regardless of actual temp, is red. That’s a nice feature and gives you a telltale as to what you’re looking at.
Physically, the device fits in the palm of your hand. There’s no focusing lenses or frills on this device, it’s as basic as you can get and still have an operational device that’s not just exposed circuitry.
The front with screen.
The side, showing the USB port and the open frame construction.
The back of the unit with the business end of the device.
Overall? This is a pretty amazing tool for $40. It’s not going to show you detailed images of something, but it’s just enough that you could spot a hotspot on a board or piece of equipment, helping you pinpoint things for further troubleshooting.
Beyond that? It’s just a cool toy and an amazing piece of tech.
- 2023
- Sep
- 22
Pictures from Findlay 2023
The Findlay Radio Club 2023 Hamfest was just a bit muted this year - the skies threatened rain but none appeared, so there were quite a few vendors. This year, a lot of late-model Hallicrafters SW radios showed up, I assume because people who purchased them in the 1960s are finally letting them go for various reasons. Unfortunately, with nothing to listen to on shortwave except Radio Havana, these radios aren’t of much use other than as a curiosity. The proliferation of SDR boxes hasn’t helped, considering you can get a direct entry radio that sounds good and runs on a common LiIon prismatic cell for a bill.
There was plenty of good stuff to look at regardless, and some good things to take home. Here’s my memories of the show, some of which were of unique pieces where the photo ended up on other sites.
One of those shots was a relatively rare signal generator from a long-dead company, Measurements Corporation of Boonton, NJ. According to the site admins, this was the only in-the-flesh image they’ve seen. I was happy to contribute to the community’s knowledge base. Check that entry out here: https://www.radiomus … rd_generator_82.html
Now, on to the good stuff!
- 2023
- Sep
- 17
A Supercapacitor UPS? Does it work?
I picked up a couple of cheap ($25ish) Supercapacitor UPS devices from AliExpress. I wasn’t sure what to expect from them, but they work surprisingly well. This is a true UPS, and stores enough power to shut your device down gracefully - not hold it up for hours.
I’m doing some testing and will post my results in a few weeks. Stay tuned!
- 2023
- Sep
- 14
Findlay 2023 has come and gone.
Rain threatened but didn’t invade this year, so there was a decent number of vendors and some good stuff to see. Pictures from the show are coming soon, I’m processing them and hope to have them up next week.
I find myself bringing home less and less each year, as I’ve already accumulated as many boat anchors as I can handle, and I didn’t see the few I’d like to acquire at the show. I limited myself to some meters, some oddball parts, and a few collectible items that looked interesting. Nothing really special, just neat.
A couple of Weston meters, an antenna for a scanner, some carbon resistors, a weather radio clock, some wall warts that were 50 cents each, and a couple of old UK radio magazines. I’ll probably go back for more magazines, since that guy was local to my home area.
Stand by for the show pictures…
- 2023
- Sep
- 7
Neat things at the Johnstown Swapper’s Day 2023
I usually don’t take any photos at this event, because it’s just a general flea market - but things of interest do show up there from time to time. While these items aren’t all related to electronics, I still found them interesting enough to snap a shot.
Someone found some a variety of late 1960s and early 1970s Skidoo snowmobiles and brought them for sale.
A “Mercedes Gazelle” built on a VW chassis. The Bug was a popular platform for modification and, at one point, you could make it look like just about anything you wanted.
A nice Sparton 667 radio. Everything was present, and the chassis looked unmodified and clean. It had what appeared to be a number of gel electrolytics, so hopefully whomever brought this home doesn’t just plug it in.
I didn’t get the model of this Zenith console, but the chassis was similarly clean and unmodified. The record player had been removed, however, but that’s not a terrible loss - chances are the stylus was long dead and unobtanium.
The rest of the trip was just your standard flea-market stuff, and I ended up going home with a small album of 78s and a few tools.