Practical PIC Projects


Terminator T800 LED Eyes
for PIC12F629 (#101T8)

  • Description
  • Operation
  • Circuit Description
  • Construction photos
  • Firmware



I'm a big fan of the Terminator film series and earlier this year I came across a T800 resin model in a shop and decided it would look good in my workshop.   These models are readily available from lots of sellers on eBay and elsewhere.

So it looked pretty cool but the eyes let it down, it just looked like a dead Terminator.  I did a bit of investigating and found the red eyes on the model were easy to remove, further investigation saw a couple of 5mm holes drilled through the eyes of the skull and a two red LEDs fitted - it looked really good but I thought it would look better if those LED eyes could be animated. I have a previous project that uses 3 channel PWM to control RGB LEDs so I took that and used two channels and some new sequence data to animate the Terminators LED eyes.

Follow the rest of this web page to see how it was done, and if you like it, there's a kit available with the electronic bits so you can make one yourself.



It uses a microcontroller with software based on the RGB Mood Light project and some custom sequences to animate the LEDs so they don't just glow red but can fade and flash independently.   The whole circuit operates from 3 volts using a couple of AAA batteries which will run for many hours.

A single push button switch is used to control it.

When off, Press for 2 seconds and release to bring it out of standby
When on, Press for 2 seconds and release to go into low power standby


A single short press will freeze / run the effect.

A double press (think double clicking a mouse) to switch to the next effect.  There are 6 effects and 3 markers so you can keep track of where you are as you double-click through the effects.

  • Effect #1
  • Marker: Slow blink right eye (as you look at it)
  • Effect #2
  • Effect #3
  • Effect #4
  • Marker: Slow blink left eye  (as you look at it)
  • Effect #5
  • Effect #6
  • Marker: Slow blink left+right eyes
  • ...returns to Effect #1

At 10 seconds after the last switch press, the current effect/mode is saved to NVRAM so it always powers up using the last saved effect, even if the power/batteries are removed.



Circuit Description

Since this is based on the RGB101 Mood Light project (see here for details) I'm not going to go into depth on the details of the circuit and operation.

The circuit used here is a cut down version of the RGB101 project.  Since we only need two Red LEDs and it operates from a 3 volt supply the original voltage regulator, driver transistors and multiple LEDs are not used.  The firmware is the same but the sequence data has been customised to generate suitable effects for the Terminators two eyes.

Power Supply

The project requires 3 to 4.5 volts to operate and as shown here it runs from two AAA batteries at a nominal 3 volts.  The power consumption is minimal and the circuit will run for many hours on a set of batteries.

If you wanted to run it from an external power supply, the PCB has the option to operate from 9-12 volt supply if a 5 volt regulator is used on the board. (See original RGB101 project for schematic)


Construction photos:

PCB Assembly

It's not too difficult to put this board together but a soldering iron suitable for electronic assembly and previous experience of soldering is advised.

Parts required to assemble kit

  • 2 x 330R resistor
  • 1 x 10K resistor
  • 1 x100nF capacitor
  • 1x 22uF capacitor
  • 1 x 6mm tactile switch
  • 1 x 8 pin socket
  • 1 x 12F629 pre-programmed
  • 2 x Red 5mm LEDs
  • 1 x AAA battery holder
  • wire for connections.
  • Picprojects PCB101

Buy this kit of parts from the Picprojects store


Fit the three resistors. These have coloured bands on them and it is important they are fitted in the correct positions.

R4 & R5: orange-orange-brown-gold


Also fit the two wire links (arrowed green in the photo) to positions D1 and IC2. Use the excess lead cut from the resistors for these links.

Fit IC socket, switch and capacitors C1 and C2. 

C2 must be fitted the correct way round as shown in the next photo.

Capacitor C2 has a white band down the side (arrowed green in photo).  It must be fitted so the white band is towards the outside edge of the PCB as shown here


Note wire links fitted to positions D1 and IC2.  Since the actual components aren't used in this application the wire links are required to jump the electrical connections.

Solder fly leads to each LED as shown.  Note the flat on one side of the LED plastic body.  This denotes the cathode terminal.  Solder a green wire to the pin nearest the flat and the red wire to the opposite pin

Solder the LED fly leads to the main PCB as shown.  It is important that the LED anode and cathode terminals are connected the correct way round.  If they are connected the opposite way round they won't light.

Pass the battery holder leads through the centre hole and solder to the positions show.  (although it is marked 12 volts you must not exceed 4.5volts since we are not using an onboard voltage regulator)


Install the PIC microcontroller into the socket.  It has a dot and notch in the plastic package at one end.  You must fit it with these towards capacitor C1 as shown above.

Overall view of the completed PCB


Modifying the Terminator model

Carefully lever the eyes away from the resin body use a flat blade


On all the ones I've done so far, they have come away quite easily.

Both eyes removed and ready for the head to be drilled

Take the eyes and use fine sand paper to remove the silver paint from the back. 

On two of the models I've done the back of the eyes were slightly concave.  In this case you may need to scrape the paint from the centre  otherwise you will sand away to much material. 


Drill a 5mm hole into the centre of each eye.  You may want to mark the centre before drilling as I found it difficult to keep it centred.

Drill from the front to the back.  You may find the resin blows out as the drill comes through the other side and you wont want this to happen on the front.

I used a Dremmel to remove some additional material at the back to allow the LEDs to seat fully in the holes.

Quick test with the LEDs installed before permanently gluing in place

Hot-melt glue is used to fix the PCB and LEDs into the top of the skull. 

 I've done a couple of these and found the resin shape inside varies quite a bit.  On this one the PCB seated okay but another one I did required some material removing with the Dremmel to allow the four corners of the PCB to seat better.


Glue the eyes back into the front of the skull.  You only want the glue on the very outside edge, not all over the back.  It's a bit tricky to do this with hot-melt glue so you might want to try some other adhesive or silicone sealant that allows more time to apply and position the eyes before setting.


The modified T800 complete and powered up.

The modification in the next two photos shows how a switch was fitted into the side of the skull.  It uses a tactile switch with a 9mm long button.  A hole was drilled through the skull and the back of the skull ground away with a Dremmel so the button just protrudes through.

(this additional switch is not supplied in the kit)


On the inside of the skull the switch is hot-melt glued into place.  Be careful not to get glue under this switch and onto the button itself.

It is wired in parallel with the switch on the main PCB.  Either switch can then be used to control it. 

Photos below show the larger T800 model.  The head is physically the same size as the one above but the top of the skull lifts off rather than the whole top and face of the other model.

With this one I used an external power supply connecting at the base of the skull so there are a couple of extra components on the PCB.  I used four plastic PCB pillars to space the PCB and hot-melt glued them to the inside of the skull.  This layout would work just as easily with a battery powered version above. 





The firmware is for use with a PIC12F629 microcontroller.

The HEX file is ready to program straight into the PIC. 

Not got a programmer?  Buy a pre-programmed PIC or kit with all the parts from the On-line store

Description Filename Download link
HEX file ready to program into the PIC
for use with
Checksum 0x


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