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Tools

This section is not about tool collecting.

It is about the minimal set that helps you safely assemble a device, verify connections, and find simple errors without guessing.

In homemade devices around iDryer and 3D printers, tools are needed for practical tasks:

  • check if 24V is present on the power supply;
  • understand if plus and minus are swapped;
  • check continuity on a wire;
  • test a thermistor;
  • see if UART signal arrives;
  • flash a controller;
  • make a proper connector;
  • find power supply sag;
  • understand why a fan or heater doesn't turn on.

Minimal set

For most simple builds, useful tools include:

  • multimeter;
  • USB-UART or USB-TTL adapter;
  • soldering iron;
  • crimping tool;
  • wire cutters and stripper;
  • heat shrink tubing;
  • proper terminals and connectors;
  • ST-Link if you work with STM32;
  • oscilloscope or at least a multimeter with frequency counter for more complex diagnostics.

Not everything needs to be purchased at once. But a multimeter and proper wire tools usually pay for themselves quickly.

Tools don't replace understanding

A multimeter does not make the mains part safe.

A soldering iron does not fix a bad schematic.

An oscilloscope is not needed if plus and minus are swapped.

So the order is:

  1. Understand what should be connected.
  2. Check power supply.
  3. Check wiring.
  4. Check sensors and signals.
  5. Only then look for complex problems.

What will be in this section

  • 02-multimeter.md - measuring DC voltage, continuity, resistance, fuses and why current measurement is more dangerous.
  • 03-usb-ttl-adapter.md - USB-UART adapters, TX/RX/GND, 3.3V/5V logic levels, flashing and logs.
  • 04-soldering.md - soldering wires, pads, modules, cold solder joints, heat shrink and strain relief.
  • 05-crimping-connectors.md - Dupont, JST, ferrules, Faston, terminals and crimp quality checks.
  • 06-st-link.md - ST-Link, STM32, SWD, board recovery after failed flashing.
  • 07-oscilloscope.md - PWM, UART, power sag, noise and critical safety warning about mains voltage.

What's worth buying properly

There are things you should not economize on:

  • a multimeter with proper probes and continuity mode;
  • a soldering iron with temperature control;
  • quality solder and flux;
  • a crimping tool for specific terminals;
  • connectors and terminals rated for the needed current;
  • heat shrink tubing;
  • wires of correct gauge.

Poor crimping or weak terminals can cause more problems than bad firmware.

What you cannot do

You cannot:

  • measure resistance on an energized circuit;
  • measure current the same way you measure voltage;
  • poke a multimeter into 110-230V AC without understanding safety;
  • solder the power part "somehow";
  • use Dupont for a heater;
  • change wires while power is on;
  • keep open mains parts on the table;
  • think that if a wire "holds", the contact is good.

The essentials

  • Multimeter is the first diagnostic tool.
  • USB-UART is needed for logs, flashing and communication with UART devices.
  • Soldering and crimping are different tasks, and for connectors, crimping is often better.
  • ST-Link is needed when you work with STM32 and SWD.
  • Oscilloscope is not needed by everyone, but it quickly shows signals, sag and noise.
  • For the power part, contact quality, wire gauge and safety matter more than assembly looks.

Reference materials