CPU Thermal Sensor and Display for Accelerator

[eva]

Hi, I just finished a mod to the Amiga case that displays the temperature and wanted to share it. My Blizzard gets hot - some WHDLoad games make it get hotter than I like, so I added a thermal sensor for the accelerator with a nice gauge-like display and happy with the results. The installation is very simple actually. The only annoying thing is cutting the Amiga case which is REALLY annoying.

Preliminaries

It may be worthwhile to mention that I am using a modded PC power supply so I did not expect any issues when performing this mod. This mod should work alright on the standard power supply shipped with the Amiga but you may want to grab a display that has a very low power rating (in Watts). The LCD displays do not need that much power, but, as always, it is best to get a device that consumes as little power as possible.

Temperature Display with Sensor

First you need a display with a flat sensor:



This is not too much of a big deal, you just need to find one on e-bay. Most of them are ready-made! You get a display along with a temperature sensor. There are very many of them on ebay, especially if you can order from China. Here are a few I can find:

• http://www.ebay.com/itm/LCD-C-F-Rang...-/190582667306
• http://www.ebay.com/itm/DC-AC-12-24V...-/371267625030
• http://www.ebay.com/itm/Red-LED-Digi...-/371249920086

You would need a 12V or 5V DC display and make sure that it will fit in the case.

Tapping from Power Socket

The second step is to tap some current. I have tapped into the main power plug by soldering the wires directly (in parallel) onto the power leads. A good idea is to use an Ohm-meter to check that the leads are correct. A sketch of the power plug is:

           +-----+     +-----+
           |      \___/      |
  +12V ------>*           * <----- GND (0V)
           |        *        |
           |        ^        |
           |     *  |  *     |
           |     ^  |  ^     |
           +-----|--|--|-----+
                 |  |  |
                 |  |  |
                 |  |
             Shield | +5V
                    |
                  -12V

So you will have to measure to see which pin on the connector corresponds to which pin on the interior of the socket.



You may need to check the display and it should have three wires: red (+12V or +5V), black (GND) and the wire that goes to the temperature sensor.

If you have a 12V display (like me) then you will connect the red 12V wire from the display to the +12V pin. If you have a 5V display, then you would connect the red 5V wire to the +5V pin. Finally, the black ground wire goes to the GND pin on the socket.

Cutting the Case

Cutting the case so you can fit the display on it is quite the pain. I guess the best way to cut would be to get a Dremel hand-held flex.

http://www.ebay.com/itm/Dremel-Model...-/381162345525
http://www.ebay.com/itm/For-Dremel-C...-/361153631316

Not having one, I have used some callipers, a cutter, a triangular file, another small knife and loads of free time. I spent like 90% of the time on this mod just to cut the case and to make sure it is straight. I measured the size of the display, then placed a few dots and lines on the case and then had fun with my makeup kit. Really nasty method but it worked after spending an hour or two on it.

Fitting the Display

When you fit the display in the case, I suggest resisting the urge to use superglue. A better method is to use a plastic glue gun:

http://www.ebay.com/itm/1Set-DIY-Jew.../221610182835?

This is because if you ever want to change the display, the plastic from the glue gun is easy to cut - it is actually more like "rubber" than plastic even though it is called a "plastic glue gun". It does hold the display in-place, but if you apply force to remove it, you can easily do so.

Fitting the Sensor Probe

You need a flat sensor probe. Then you can take the wire, pass it over the circuits and slide it under the accelerator. I sticky-taped it with some thermal tape to the CPU of the accelerator.

Sealing the Light Bleed

One thing that I added in the end was the dish that you can see in the later shots. Also, I have used some black silicone (also on e-bay). Here is one I could find with a search:

http://www.ebay.com/itm/CAR-BLACK-SI...-/151516810165

If you compare the first pictures I posted, to the later ones, you will see that in the first pictures the light "bleeds". This is because the display I bought was not isolated properly. It had a few slits that were open so I used the black silicone to seal them and prevent the light from escaping.



Be careful with that black silicone - it smells like vinegar, dries up pretty fast, it is toxic. In any case have plenty of wet wipes ready and be prepared to take a break and go to the bathroom and wash your hands (soap works fine).

You will need to let it dry up for approx 2 hours before attempting to fit the display. After that give it peace another 24 hours and the solvent in the silicone will evaporate and you will be done.

[crazyc]

This is fantastic - more pics of all of it please!

[BigFan]

Cool stuff. Did you add fan control, or is it just reporting?

[eva]

Thanks! I'm still not happy with it because I should have added a thin layer of plastic between the indicator and the case - I'll just need to find some plastic at some point.

It just indicates the temperature with a sensor that is attached to the CPU of the accelerator. There is no fan control yet. So far I am happy because the CPU on normal usage seems to stay between 45-50.

I know one game for example that I recently played: Legend of Kyrandia and for some reason during that game the accelerator seemed to burn up! So after some scary sweaty hot flashes I decided to add this temperature indicator so I can keep an eye on things.

Perhaps I could add a potentiometer next to control the fan speed. :-) Not sure yet. The problem with these assertors is that the CPU is facing downward.. I have already cut a small slice to give it more air, but there's just a limited number of things you can do if you want to keep the original wedge shape.

[eva]

Attached another shot. I took care of the light bleed with some black silicone. I also mounted a small white frame for the display. I am happy with it now. :-)

[UncleSpam]

If your CPU is running too cool, you need a fancier screen saver

Good job!

[crazyc]

Can we have full pics and instructions?????

[source]

How can we make this for ourselves? That looks great. I have wanted this for my machines, but did not know how to make it.

[eva]

Hi! Thanks for the heads-up. I posted some notes from my install. I hope that's helpful. I am going to end-up opening my Amiga sooner or later so I will update the thread with some pictures.