I use CubeMX to verify the wiring of my Boards and one of the features I like is that it auto-generate a report like the one below. Just click on the link and you can see the full report of the 7xStepper Hat. 7x5WStepper This is basically information that is very handy to have available…
My STM32 Tester finally arrived, and 12 rejected MCU’s which is ca 40% of all STM32F405’s I had is the result. The sent me a different tester than I ordered, but it did the trick. One MCU broke under testing as well. 10 x STM32F405RG cost va 45.- USD from China and ca 90.- USD…
To effectively have a small production line you need to have 3 pieces of equipment/processes. First step is using a stencil to apply solder paste. this can be done with a stencil alone as a mask on top of a PCB, but a better way is to use a 200.- USD stencil printer. This pic…
One of the challenges I face is that I would like to start producing electronics in volumes, but assembling at an factory is expensive. It easily add 50-100.- USD to unit cost at low volumes and I don’t have the financial backing to go high volumes. One alternative is to use an Asian factory, rather…
I do at present have 8 PCB’s + 3 designs I have not ordered yet in my modular control system, so I have a far to large backlog of electronics that need testing and code. The difference with my last 12 x PWM Hat is however that it target a project – my upgraded 3D…
I decided to Change the 12 x PWM Hat to use High Side Current Sensors. Below is the schematics of the new sensors. This means I measure current out on each PWM signal. Using high side sensors actually simplified the routing so it was a straight forward change. The reason I started with low side…
The 2 blue signals crossing the bigger, red Power lane is asking for trouble. The blue lanes are 0-3V ADC signals, while the power lane is feeding PWM MOSFET’s. What will happen is that PWM noise from current spikes will jump over to ADC signals and create a false current signature. But, I believe it…
I must admit that sourcing for STM32F405RG is an issue. I have bought batches from China and I am rejecting a lot of MCU’s. The worst is actually the time to solder them on before I can test, so I seriously need the tester shown in my last article. This is worst as I like…
Finally – I just discovered test boards with sockets for STM32 LQFP64 and LQFP100. They are a bit pricy – ca 65.- USD yet, but it is a start. These are on the list of things I planned to make because I could not buy them.
I currently plan using INA194 that have a 50x gain. As our max voltage in is 3.3V this means the max voltage over the shunt need to be 3.3/50= 66mV. Given a max current of 2.5A that gives a Shunt resistor R = V/A = 0.066/2.5 = 0,0264 R or 25mOhm. Now – 2.5A over…