Hello EEVblogers!
This is actually my first post on this forum. I ocasionally watch Dave on youtube, and ofc, he recomends his forum, so that is the reason I wanted to share my master thesis project with you. The project I'm going to talk about has been in my mind for quite a while now, but since i had classes and exams, I never really had the time to do it. I recomended this project to my mentor at my university and he agreed I should do it as my master thesis. At first, the project didn't seem that hard to do and I was afraid it was too easy of a project for a master thesis, but now that I am a couple of months in, I think its quite OK. Anyway, this is it, please dont shit on it, I want your honest opinion.
Being a person from Croatia, interested in engineering, never had money, I allways found a way to do a project cheap and easy. Doing the projects, I never had any good equipment. Cheap soldering iron and multimeter from China were, and still are my best equipment. A friend has a SMD oven so I dont have to worry about SMD components. The next thing, in my opinion, a young engineer needs a good adjustable power supply. Since power supplies on the market are mainly big and bulky, but also non user-friendly and can be expensive, and me, never really needing more than 12V, 1A, I've set a goal to make myself a cheaper, smaller and portable power supply, instead of constantlly using 9V batteries or 5V USB power banks or buying a bulky power supply.
The first thing was to set some rules. I followed Dave on some, but I have also made some of my own:
- 12V 1A supply (1A @ 12V max)
- constant voltage, 100mV step, can be more precise down to 10mV
- current limit/constant current (0-1000mA), 1mA step
- current draw measurement (0-1000mA)
- linear voltage output (low noise)
- output down to 0V
- button for load disconnect
- battery powered/uninterupted portable supply (Li-ion)
- 12x12x5 cm max
- touchscreen for ease of use(can be used to set everything, cheap resistive ts)
- incremental encoder for smooth parameter setting (infinite turns,Dave: encoder is a must, better than pot)
- 4mm banana female connector (OUT and GND)
- bottom breadboard connector (you can plug breadboard on the bottom of the supply)
Picture you can see on a link below is a rough sketch of it, so you get a basic feeling for it. It is not a final design.
https://prnt.sc/jtyy3fhttp://prntscr.com/jtzrnzI got the touchscreen and wrote a lib for it, I'm using STM32L4 MCU, wrote a lib for encoder, and after all, in a couple weeks or a month, I've made a detailed schematic, simulated it, drawed it in the pcb designer and sent it to be made. Before I continue, I have to say, whenever making a project that requiered a PCB, I went with a local manufacturer in Croatia, payed 40$ for 5 PCB, waited a week and had to pick them up. Now for the first time I tried something else and I was pleasantly suprised. I saw on Great Scotts channel on youtube, JLC PCB manufacturers, and decided to give it a try. They have an offer on 10 PCBs for 2$!!!! DHL costed me 23$ and everything came to my doorstep in 5 days time. It is odd to pay 10 times more for the shipping, but the PCBs are high quality. I never before used 0.3mm vias
They are really great and you should check them out.
https://jlcpcb.com/PCB:
https://prnt.sc/jtzopcNow I'm just waiting for the components, Ill solder them on and test everything with a MCU i have on a separate board.
Anyways, what do you think about my project? Is there something to add or remove? Is is good and would you like to have one of these?