Mr Blinky

Solar Monitor 5 Million I have been meaning to write this up for a couple of weeks now, and I finally do it. This is an experiment I am conducting (very loosely at present) that came about from leaving my CAJOE RadiationD-v1.1 with J305by on my window sill for a week and noticed a strange pattern with the 'excess' counts. They were stronger in the morning than in the afternoon, even to the point they were stronger than in direct sunlight. I mentioned this to a couple of members here and we all agree that it is strange, and that we all expected there to be more counts in direct sunlight than

I knocked up a simple monitor to easily see if radmon.org is up or down. It uses an ESP8266 (Wemos D1 mini clone) and a single RGB LED. It simply polls radmon.org by asking for a response from the server. If it gets the reply it is expecting in a timely manner it lights the LED green. If it doesn't get the reply it wants, or times out, the LED changes to orange and sets a fail counter +1. If it receives the correct reply again it goes back to green, but after 3 consecutive failures the LED lights red. There really isn't much more to it. There are positions in the code where an alarm or

I have been testing a new GM tube for the past few days, a Robotron 70 013. Its quite a sensitive tube at around 100 CPM for background count. I got to thinking "would a more sensitive tube last as long as a less sensitive tube" so threw some numbers together to find out. My Initial thought was "if the more sensitive tube clicks more, then surely it wears out faster." I'm comparing the SBM-20 (~20 CPM background) with the Robotron 70 013 (~100 CPM background) The SBM-20 has a life of around 20,000,000,000 pulses. The Robotron has a life of around 60,000,000,000 pulses. That settles it, right?

Below is a list of conversion factors for GM tubes that I have been collating over time. They may come in handy if you are building your own Geiger counter and want to convert from CPM (counts per minute) to μSv/h (micro sieverts per hour.) RH = values from RH Geiger SBM20 0.006315; SBM20 0.0057; - RH SI29BG 0.010000; SI29BG 0.0082; - RH SBM19 0.001500; SBM19 0.0021; - RH STS5 0.006666; STS5 0.0057; - RH SI22G 0.001714; = 583.43 SI3BG 0.631578; SBM21 0.048000; LND712 0.005940; SBT9 0.010900; SBT9 0.0117; - RH SI1G 0.006000; SBM-20 - conversion factor 220 CPM -> 1uSv/h (working voltage-

I wanted to see if there was much difference between the sensitivity between a SBM-20 and STS-5 tubes. For a background test I had an SBM-20 running for a while then swapped it for a STS-5. I think the graph says it all. (Note - there was a discrepancy with the initial background test (below). The test was repeated later and the results are shown towards the end.) I took this a step further and compared the two tubes using 13 different sources. In hindsight I should have tested a J305 at the same time. It took a surprisingly long time, so I might set up some kind of testing jig and program an

It seems of late that getting hold of good GM tubes, for reasonable money is a thing of the past. A single SBM-20 on eBay is going for in excess of £150 ($182) and there are hardly any suppliers left for them. Some years back I paid about £13 for a NOS SBM-20. I wish I had the nous back then to buy a large stock of them. I'd have made good money these days! eBay used to be awash with good GM tubes. Lots of regular types, SBM-20, STS-5, LND-712, SBT10A, SBT11A, pancakes, a bunch of Mullard and then a load of quite exotic tubes. Today there is hardly any of those and is covered with cheap

If you are interested in Chernobyl you will love this video. I had only heard of SKALA in the past, but nothing actually about it. This video gives a really good look into SKALA and it's operations. In this episode of Computers of Chornobyl series, we will talk about the mighty SKALA system, that controlled the RBMK reactors. This is the first-ever documentary about its design, architecture, operation, and software. It also tells the story of how it was preserved for posterity and reveals, what is common between it... and a control computer of Apollo spacecrafts. It took us nearly half a year

I bought one of these cases from my local Asda for about £14 a few years back. I thought it was that good I went back a week later and they had sold out and they never came back into stock again. I had a little search about on the internet and found them on eBay and Amazon - links below. I bought one from eBay to see if it was the same quality, and it is exactly the same. It is a really neat case. Appears to be very waterproof, even air tight and strong. I think it is made from Polycarbonate. I used mine to house a GPS Geiger counter project some time ago. I think I will use another for an

For all of the posts in the Negative Ion Energy Ju-Ju series, click here. I found a new variation of the pendant. A white Ju-Ju pendant. I think there are loads of variations but this seems a new one. I have one on the way so will let you know about it when it arrives. https://www.aliexpress.com/item/4000030351480.html Update: It has landed! This is the latest Negative Ion Energy Ju-Ju pendant. It's kind of pretty. File Attachment: It has some extra goodness on the back - some Germanium stone and FIR stone little dot kind of things. One of the previous stone coloured pendants has 4 little dot

I was asked by Gissio to try and download the original firmware from my HFS-P3, so I tried. Alas, no joy so far. ☹️ Under the battery (stuck down with sticky tape) is a pin header. Probably designed to have a pogo pin connector connect to it as there is no room to solder on an actual pin header. I just soldered wires to it directly. I managed to work out the pins by tracing the circuit, but I had to use my microscope as the connections on the MCU really are that small! I took photos of both sides and flipped one then overlaied one over the other so I could line up the vias on the board. You