Following on from Incony's work on detecting water leaks on the coolant system, and my previous thermal imaging of the coolant tank, I have now completed testing an alternative sensor that I hope to use to detect low coolant level.
The sensor is made by Balluff, a well known automation sensor manufacturer, and was kindly given to me by the company's local rep as a free sample. They retail at about £40.
It is an ultrasonic device and will detect liquids through non metallic containers, using an effect similar to radar.
I have made a mock up system using a spare expansion tank and a spare instrument console (kindly given to me by Darren at Bitz).
The device works great on 12v, so it can be used directly on the car without any voltage conversion, however the signal is normally open (off) when liquids are not detected, so I used a relay to inverse the switched output of the sensor so it will light up a lamp when the sensor turns off.
I used the gearbox fault indicator lamp on the instrument console, as it does not have the low level warning indicator, being from a 2003 car. The instrument console on my TF is a similar unit, so I will probably wire this the same way when on the car.
When the coolant level drops to about 5mm below the low level line the sensor switches off and the alarm light comes on.
It is connected to the IGN terminal on the console for +12v and GND for 0v so the whole circuit switches off when the ignition is turned off, saving the battery drain that the sensor would cause.
As the gearbox sensor lamp is connected permanently to the IGN supply and switches 0v to light the lamp, I used the relay to switch a 0v to the lamp when the level drops.
Here is the sensor on the tank, sitting in a useful rig knocked up out of Meccano
This is when the coolant level is ok....note the green led on the sensor for power on and the yellow led for liquid sensed.....
Now drain a bit of coolant out with my turkey baster coolant tester...
And then when the level drops below the sensor trigger level, the warning lamp comes on.
The next step is to now fit on to my TF and hopefully the sensor will be able to stand the ambient temperatures around the coolant reservoir. The sensor is rated at 85 degC but the rep said it will take more, so it will be interesting to see how it performs.
The main advantages of this sensor is that if the sensor fails, the light will come on automatically, saying there is a problem, also the sensor clips onto the tank, so can be fitted without removing the tank and draining out coolant.
On the minus side, I have to get a cable to my instrument unit, which is not that bad a job really and I have to fetch out the unit anyway, as I have to replace the binnacle soon as mine has a few cracks in it.
Sundance
The sensor is made by Balluff, a well known automation sensor manufacturer, and was kindly given to me by the company's local rep as a free sample. They retail at about £40.
It is an ultrasonic device and will detect liquids through non metallic containers, using an effect similar to radar.
I have made a mock up system using a spare expansion tank and a spare instrument console (kindly given to me by Darren at Bitz).
The device works great on 12v, so it can be used directly on the car without any voltage conversion, however the signal is normally open (off) when liquids are not detected, so I used a relay to inverse the switched output of the sensor so it will light up a lamp when the sensor turns off.
I used the gearbox fault indicator lamp on the instrument console, as it does not have the low level warning indicator, being from a 2003 car. The instrument console on my TF is a similar unit, so I will probably wire this the same way when on the car.
When the coolant level drops to about 5mm below the low level line the sensor switches off and the alarm light comes on.
It is connected to the IGN terminal on the console for +12v and GND for 0v so the whole circuit switches off when the ignition is turned off, saving the battery drain that the sensor would cause.
As the gearbox sensor lamp is connected permanently to the IGN supply and switches 0v to light the lamp, I used the relay to switch a 0v to the lamp when the level drops.
Here is the sensor on the tank, sitting in a useful rig knocked up out of Meccano
This is when the coolant level is ok....note the green led on the sensor for power on and the yellow led for liquid sensed.....
Now drain a bit of coolant out with my turkey baster coolant tester...
And then when the level drops below the sensor trigger level, the warning lamp comes on.
The next step is to now fit on to my TF and hopefully the sensor will be able to stand the ambient temperatures around the coolant reservoir. The sensor is rated at 85 degC but the rep said it will take more, so it will be interesting to see how it performs.
The main advantages of this sensor is that if the sensor fails, the light will come on automatically, saying there is a problem, also the sensor clips onto the tank, so can be fitted without removing the tank and draining out coolant.
On the minus side, I have to get a cable to my instrument unit, which is not that bad a job really and I have to fetch out the unit anyway, as I have to replace the binnacle soon as mine has a few cracks in it.
Sundance