Wiring

Attach Resistor to female JST connector

To start this project, we'll begin by attaching the 10K resistor to the famle JST connector. The resistor will allow the circuit to drain the voltage from the LCD panel when the switch is set off (so it's necessary if you want to be able to turn the tint on and off!). This resistor will need to be wired across the negative AND positive electrodes on the female JST connector.

Prep Female JST Connector

To fit the resistor onto the female JST connector we'll need to bend the right angle pins straight. We used flat pliers to straighten each pin. Now we can bend the pins away from each other so the resistor has enough space to fit between the two pins.

 

Prep Resistor 

We'll need to bend the legs from the resistor near the beginning of the body. Use flat pliers to shape both pins like shown in the pictures. We're basically wrapping the legs from the resistor around the two eletrodes on the female JST connector. This way, the resistor can stay in place while soldering them together.

 

Lay the bent resistor pins onto the JST pins and solder the pin together. With both resistor pins soldered to the JST pins we can shorten the resistor pins by trimming off the excess with flush cutters. But leave some metal because we need to attach wires to them.

It doesn't matter which leg of the resistor is soldered to which electrode on the female JST connector. The resistor is not polarized.

 

Once we're finished, we can set this aside. Moving forward, we'll work on using a second female JST connector for building the slide switch adapter.

Measuring Wires

It's a good idea to visualize how the components will be wired together. Here, we have the battery, slide switch, female JST connector, and male JST connector. When placed near the 3D printed enclosure arm piece, you can see how they'll fit into the enclosure. Using this visual, you can get an idea for long the wires will actually need to be. 

It's important to connect the male JST connector from the battery to the correct wires on the slide switch adapter. So we'll need to take note of were the positive and negative wires will connect.

Female JST Connector

Here's how to tell which electrode (or Pin) is positive and negative on the female JST connector. On the top side of the JST connector is a little notch on the edge – This is the positive side. Use this little notch as an indicator for seeing how to correctly wire the female JST connector.

It's suport important that the wiring is connected to the correct electrode!

Cut JST Extension Cable

Next, we'll need to cut off a portion from the JST extension cable so that we can attach the male JST connector to the slide switch. Measure the length of the cable so it's about 24mm long. Then, cut the wire (the side with the male JST connector) down to size.

Prep male JST Connector

Next up, we’ll need to attach the positive wire from the male JST cable to one of the electrodes on the slide switch. Using wire strippers, remove a small amount of insulation from the tip of the wire to expose it. Then, apply a small amount of solder to the strands of wire to “tin” them. This will make it easier to attach the wire to the metal electrode on the slide switch. Repeat this process for the negative wire.

Prep Slide Switch

Grab the slide switch and remove one of the electrodes (either the far left or right, but NOT the middle!) using flush snips. Then, “tin” the two remaining electrodes with a bit of solder.

Attach male JST Connector to Switch

Now we can work on attaching the positive wire from the male JST cable to one of the electrodes on the slide switch. Before we do any soldering, go ahead and slip on a piece of heat shrink tubing over the wires – This will allow us to insulate the exposed bare metal from the slide switch. Bring the tip of the positive wire close to an electrode on the switch so they're touching. Then use the tip of the soldering iron to heat them together, essentially soldering them together.

Male JST to Female JST Connector

Next, we'll need to connect the negative wire from the male JST cable to the negative electrode on the female JST connector. Remember, the positive side of the female JST connector has the notch. Solder the negative wire from the male JST cable to the negative electrode (the side with no notch) on the female JST connector. Be sure to slip on a piece of heat shrink tubing before soldering.

 

We’ll need to connect the remaining electrode from the slide switch to the positive electrode on the female JST connector. To do this, we’ll need a new piece of wire. This can be from the excess cable we cut from the JST extension cable from earlier. Cut it down to size and then strip and tin the wire. Now we can we solder this wire from the positive electrode on the female JST connector to the remaining electrode on the slide switch.

 

 

Slide Switch Adapter

And now we have a “Slide Switch Adapter”. So why did we make this? We’ll, it’ll make recharging the battery much easier because we can disconnect it from the circuit. We basically avoided having to cut the positive wire from the battery to wire in a slide switch. So, why not use a JST extension cable with a built in switch? Well, they’re super large compared to the enclosure, so it simply won’t fit. This is the smallest we could get this component, so it’s pretty important to make it as small as possible.

Dry Fit LCD Panel

Next, we'll work on attaching wires to the electrodes on the LCD Panel. First, do a "dry fit" and place the LCD glass panel over the 3D printed frame. This will allow us to guage the lengths of wire necessary for connecting it to the rest of the circuit. Grab the right arm (with built-in enclosure) and fit it into the hinge of the frame on the right side.

Measure Wires for LCD Panel

Now we can measure out how long the positive and negative wires will need to be. The 3D printed right side arm has the built-in enclosure, so the wires will need to reach it. They're two sets of positive and negative electrodes on the side of the glass panel. The negative wire will connect to the top left electrode, while the positive wire will connect to the electrode on the top right. Because of this, the negative wire will be longer than the positive wire. Cut the wires down to size.

Tin Wires for LCD Panel

Now we can work on preping the wires for connecting them to the electrodes on the LCD panel. Use wire strippers to remove a bit of insulation from the tips of each wire. Then, secure the wires to third helping hands so we you tin the tips by applying a small amount of solder.

Connect Wires to LCD Panel

Next, we'll trim the electrodes on the LCD panel short. Then, tin the two electrode with a small amount of solder. Now we can connect the negative wire to the top left electrode on the LCD panel. Then, connect the positive wire to the top right electrode on the LCD panel.

Connect Positive Wire

Now grab the female JST connector (the one with the 10k resistor) and secure it to third helping hands. We'll need to connect the positive and negative wires from the LCD panel to the electrodes on the female JST connector. Remember, the side of the female JST connector with the notch is the positive side!

 

That's it for the wiring! Now we can work on install the components into the 3D printed parts.

This guide was first published on Mar 15, 2017. It was last updated on Mar 15, 2017. This page (Wiring) was last updated on Sep 14, 2019.