I bought this noname kit, from somewhere in China. I may want two of these in the end, to compare radiation near one site compared with the general background, so getting cost down1 is worth having, and I can’t moan about the price, delivered for < £25 including tube. But I can moan about the total absence of documentation! You pays yer money, you takes yer choice. I looked at some of the offerings from Banggood to see if I could match it. Maybe I should have paid an extra £5 and got someone in China to assemble it for me but the board looks the same. Bangood’s board says RadiationD v1.1 (CAJOE).
It’s a tough life in Chinese electronics, even the copiers get copied. The write up is on Github – it’s a little bit obscure, the PDF overall schematic isn’t that useful but the more detailed schematic in blocks is.
Not a kit for beginners
If you are new to electronics, this kit is not for you due to the amount of guesswork and component ID required, buy it built, the difference isn’t that much. There’s nothing that special or earth-shattering in the parts however, all are easily available, and the board is a reasonably decent construction and easy to solder. There was some satisfaction in second-guessing our Chinese friends but really, how hard would it be to provide the link in a slip of paper or even on the original ad? Investigation of the original designer CAJOE with the Wayback machine at the URL indicated on the PDF didn’t deliver much enlightenment, but there’s enough in Github to give it a go. I used the block schematic with values, thankfully the screenprinting reference numbers on the board match the components in the PDF, which the exception of C5 which is MIA on the schematic, at a guess a 100nF decoupling cap.
The kit prep is a bit slapdash. The classic way to drive a mechanic bonkers is tossing some spare screws in his tin of screws taken out of the engine, and here they lob in some spare components – on populating the resistors I was left with a few over, same for the caps and a couple of transistors. Continue reading “CAJOE ebay geiger counter kit”