This metal box is not exactly the prettiest Project Box I have seen, but it cost 17.- USD including P&P and measure 250x190x110mm. I ordered one for testing because the more fancy alternatives cost closer to 100.- USD. What we now miss is the mains adapter with fuse, which is a 3.- USD component. We…
I did not add much capacitors on any of the boards simply because they take to much space + I wanted a separate capacitor board to be able to scale up/Down and be more flexible about mounting them due to their size.. I found some very nice sized 10,000uF/50V that I am using that have…
In part 1 I created an analogue linear regulator that can be used stand-alone as is. But, the drawback with a linear regulator is that it regulate by splitting voltage out between the load and the transistors. This means that if you short-cut the load you have 36V * 10A = 360W heating up the…
I desperately need more lab PSU’s and I have a bunch of LM723 and TIP3055 transistors that are excellent for creating an old-fashioned Linear PSU module. Thinking a bit ahead I want to create the analogue regulator as a small, separate module with knobs on the front, heat-sink & transistors on the back and connectors…
This drawing illustrate a water detector. A water detector is basically a standard ADC reading between two resistors where the 2nd resistor is a PCB as illustrated above. As the water raises the PCB will start leading current and the ADC reading will move from 3.3V to GND. This is the same principle as used…
One major issue is how to identify units in a network. I used STM32F030F4 on these and I absolutely love this little MCU costing 50 cent in TSSOP20 package, but it lack the serial number that is burned into other STM32 MCU’s. This serial number is crucial as it present a factory set ID allowing…
My grandparents passed away some years ago leaving a beautifully mountain farm behind. As no-one lives up there we have to leave the farm unattended for months at the time. This is a challenge in winter time as we fear the water pipes with freeze. The farm actually got internet installed so it is possible…
I just uploaded a design doc for the Universal Motor Controller on the downloads page. I used LibreOffice 5.3 since it could export to PDF, but believe me this is the last time I use that. I had so many problems importing drawings that I ended up importing everything to Word and then copy &…
This is the front and back 3D model of the Rev 1.0 of my Universal Motor Controller. I will be leaving the non-isolated RS485 for now. I want to do some changes around the MCU layout later anyway as I actually have a lot of spare pins here, but lack space to support a com…
The HEXFET on my Universal Motor Controller is 30V, so I decided to change my existing DC-DC to 12V out and add a classing LM1117 for the 3.3V. The LMR14206 based DC-DC is basically so small that it is not much larger than LM1117 on PCB space. It is restricted to ca 800mA, but it…