How many hours in your life have you spent troubleshooting a project?
Knowing your I2C from your SPI
You've spent ages connecting a bolognese of wires on your breadboard, making sure to distinguish your MISO from your MOSI, your SDA from your SCK, your DIN from your SDA, and your VCC from GND. You've already flashed your sketch to your ESP or pasted your python to your Pi.
Eagerly, you want to see your little display show the temperature of your sensor, or the stepper motor turn its gear.
You attach your power and....
Nothing.
You check your code and pinouts.
Power up again...
Nothing.
You check again.
Still nothing.
A loose connection obviously. Right? A faulty Dupont wire?
So you change the wires one at a time, laboriously disconnecting your spaghetti, making sure to place each new wire into precisely the right breadboard hole. As you do so, it disconnects from the other end, then you laboriously do the same with your device's pins.
How many times have you discovered that it was, in fact, a faulty wire? I know I have. Dozens of times. I must have spent scores of hours fault-finding, only to find that some stupid wire was invisibly disconnected from its little pin.
The Pianist within us all
You check your Duponts with your multimeter, right? You grip the pin against the probe, then fidget with your unfree hand to find the other pin, and press it to the other probe. Which works fine if it's a male to male. But what do you do with the females? The probe won't go in the hole, so you need to find the little metal tab at the side. Of course, you need to do it at both ends simultaneously - requiring the dexterity of a concert pianist.
It's just all one big mess
The Tool you Need
Wouldn't it be wonderful if we had an easy way to check our Dupont wires for faults before we put then on the breadboard?
Surely such a tool exists, right?
Where else to look but Aliexpress - that has tools for problems that don't even exist.
Nada.
Nope, no Dupont wire tester.
DIY
How hard can it be? Well, suffice to say, finding the parts in my bins of bits took longer than it took to build the tool.
And what a tool it is!
A buzzer, a breadboard, an LED and some headers. That's it. Designed to cater for male, female, transgender, and other types of politically incorrect Dupont wires. This thing checks my wires - visually and audibly - in an instant, and I'm sure it's going to save me decades of troubleshooting.
I won't insult you with a circuit diagram.
If anyone comments about my missing LED resistor, I'll just ignore you; I have a million of them lying around and a split-second three volts isn't about to fry its little crown.