5 inexpensive measuring tools I use when designing digital hardware
What are your favourite tools when building hardware?
If you're working with electronics, you need to be able to measure voltages, current, resistance and continuity. I mostly use a $10 multimeter to check if voltages are at the right levels and if there's continuity between various parts of the circuit. You'll notice there's no oscilloscope on this list. If you're only working with digital electronics, an oscilloscope feels like an unnecessary luxury. Most of what you need to figure out can be done with a multimeter and a logic analyser.
My $10 logic analyser from eBay only measures up to 24MHz, but I've been able to successfully decode USB traffic that typically would be done with a USB analyser costing 50 times as much. The open-source Sigrok PulseView software supports a wide range of protocols for decoding, and is surprisingly easy to use.
If you have a 3D printer, you're going to find digital calipers useful. It makes it so much easier to measure the dimensions of enclosures, components and circuit boards. I bought a super-cheap plastic digital caliper for $7, and so far it's been working just fine. I find myself using it so often that I could easily spend a little bit more on one that allows for finer adjustments.
If there's any kind of UART serial communication between your microcontroller and peripherals, a $5 USB-to-TTL converter is a very useful addition to your toolbox.
This may sound like an unusual addition to this list, but being able to use a $10 DVB-T USB stick as a software-defined radio is priceless if you're working on a wireless project. I've used mine to measure the length of pulses while building a circuit to communicate with a remote control socket, and to check that what I'm building is actually sending data over the air.