Thread: How to convert your ashtray into a digital engine alarm for $39

Ok so my first post with some decent pics.

I loved this idea as its exactly what I wanted. I thought about engine watch dog but price prohibitive and low coolant alarm but other things can go wrong IE: broken fan belt and still have sufficient coolant. So I settled on this.

I made mine a little different so here is my description.

I bought this Temp Display.
DC 12V Digital Temperature Controller Room Thermostat Heating Cooling | eBay

Then I bought the thermo couple as recommended by simonmelb
Thermocouple Sensors K Type With Washer | eBay

Even though the unit came with a one metre sensor it was way too short and very light weight.

I went to Jaycar and bought a small buzzer for $4

So I set it all up as a bench test but the thermo-couple wouldn't work. The display says error.

So I ordered a 2 mtr sensor.
2M NTC 10K Temperature Sensor Probe Extension Cable FOR Temperature Controller | eBay

I ended up cutting the sensor of the end of the new 2mrt cable and attaching the 1 meter original to it so I had 3 mtr in total plenty to get around engine bay fuse box area and dash.

I used the power from the plug under the driver seat as I dont know how to tap into the fuse box. The only issue with this is its constant power even with the key turned off so I run the risk of leaving the unit turned on when exiting the vehicle.

I then removed the face plate from the coin tray used a digital vernier caliper to scratch and mark out the dimensions of the display unit.

I took a renovator tool and cut it out. WARNING: I broke the first one because the tool was blunt it vibrated too much in the vice.

So I bought a new one from someone wrecking a D2 and a new blade.. So more expensive than I had budgeted. $22 total.

The sensor has been fixed to the area right were the temp sensor goes. Photo shows how I did it. I used a small clip drilled slightly to clamp it in place it makes perfect contact with engine.

So after several prototypes I used a hacksaw blade with rescue tape on the ends (Cut to size) as the piece that keeps it all in place.. It clips in underneath the display in the rail that the coin tray used to slide on.

I used a butter knife to shimmy the unit in place it has come up a treat.

PS I would have pasted photos within the post but I don't know how so I have used them as attachments Im sure you'll get the drift.

So total cost.+- $50

Display $14.
Thermocouple(not used)$6
Second 2mtr Sensor $4.50
Buzzer$4
Extra Face Plate and Blade$22
Wire, Tape, Sensor Clamp, $0

Tested today and it registered just on 80 degree so I set the high temp alarm to buzz at 87.

I really am very happy with the outcome.. Took a while to get bits together.

After doing the head on my D1 I purchased a TM4 watch dog. I purchased a new head from Turners and I asked them what the Max temp I should allow.

They told me 110 degrees is ok so I set my alarm at 115. On really hot days and when towing the alarm often goes off.