The latest articles on DEV Community by Cyber (@cyber1998). https://dev.to/cyber1998 https://media2.dev.to/dynamic/image/width=90,height=90,fit=cover,gravity=auto,format=auto/https:%2F%2Fdev-to-uploads.s3.us-east-2.amazonaws.com%2Fuploads%2Fuser%2Fprofile_image%2F235953%2F8f80d9df-cb06-4a41-ac59-b39f8f8495a5.png https://dev.to/cyber1998 en Cyber Sat, 17 Oct 2026 00:00:00 +0000 https://dev.to/cyber1998/why-i-built-a-raspberry-pi-simulator-c8i https://dev.to/cyber1998/why-i-built-a-raspberry-pi-simulator-c8i <p>I'm a backend engineer. I've wanted to go deeper into Raspberry Pi hardware for a long time, but between work and personal life I never had the time, or the budget, to keep buying parts, wiring them up and working out why they didn't behave.</p> <p>So I built the thing I wanted: a simulator that gets the electrical side right enough that what I learn in it carries over to a real Pi.</p> <h2> What "right enough" means </h2> <p>A lot of simulators treat a pin as on or off. PyRasp solves the circuit instead. Every step runs nodal analysis on a netlist of resistors, sources and diodes, so an LED's brightness comes from the current through it, and a GPIO pin sags when you load it, because it's a source behind about 40 Ω.</p> <p>That also means you can get things wrong the way you would on a bench. Pull more than 16 mA from a pin and you get a warning; pull more than 50 mA for half a second and the pin is damaged for the rest of the run.</p> <h2> Real Python, real libraries </h2> <p>Your <code>main.py</code> runs in CPython in the browser, with the real gpiozero library. RPi.GPIO, smbus2, spidev and the rest talk to simulated I2C, SPI, UART and 1-Wire buses, so a sensor driver reads registers the way it would on hardware.</p> <h2> What's next </h2> <p>It's a DC solver today: no capacitors or inductors yet. The next big piece is a transient solver, checked against ngspice, so RC timing and the spike a relay coil makes when it switches off can be simulated too.</p> <p>You can <a href="https://pyrasp.com/try" rel="noopener noreferrer">try it without an account</a>. If you've built these circuits on a real Pi and something behaves differently in PyRasp, I'd like to hear about it.</p> raspberrypi python electronics showdev