Anyone that has had to traverse an area of soft sand with his vehicle, and possibly trailer, knows that an essential part of that process is aggressive deflation of all tyres. And that means re-inflation as soon as possible after the process is complete, since driving with wheels deflated to 1,1 bar will quickly lead to sidewall damage and tread separation. Anyone who does this regularly knows that it stops being fun after the first time, sometimes even sooner. Squatting beside each wheel for long minutes on protesting knees while the air bleeds out ever more slowly is something that only young people should indulge in.
To relieve me of this unwelcome duty I created a microcomputer device that could:
· Communicated with my mobile phone via Bluetooth.
· Switch the heavy 12V DC current required by the compressor
· Operated a solenoid-activated deflator valve
· Measure and report air pressure within the inflator hose
· Do some arithmetic
I then wrote an app for my mobile phone that could:
· Display the air pressure measured by the remote device
· Command the remote device to switch the compressor
· Command the remote device to activate the deflator valve
· Send a user-defined target pressure to the remote device
· Command the remote device to seek this target pressure
· Operate the flashlight.
The compressor and deflator valve can both be activated from the mobile phone or a target pressure can be dialled in and the remote control commanded to seek this pressure. Since the pressure measured in the hose does not reflect that in the tyre once air starts to flow in either direction, the remote device estimates the time required to reach the target pressure and initiates a cycle with the remaining time displayed on the mobile phone. The size of the tyre (large, medium, or small) is specified to assist with this. If the target pressure is not reached at the end of that cycle subsequent cycles are initiated automatically until the tyre pressure is within 50 mbar of target.
The whole system needed to be housed in a container, for which purpose a high-lid ammo box proved eminently suitable, after the lid was hinged into place and those pesky snap-clips were done away with. Should the remote control not be operational for any reason it can be bypassed by connecting the IN and OUT Anderson plugs directly to each other. Similarly the quick-disconnect coupler can isolate the remote device from the air hose.
That annoying always-too-short spiral plastic hose is discarded and replaced with a generous length of silicone rubber compressor hose. A good quality deflator and pressure gauge to use as back-up is also a good investment.
There are undoubtedly many cheaper methods of achieving the same end – I’ve used most of them myself – but this is my most elegant solution thus far. Aside from the remote control all of the components are available from camping and 4×4 shops and the app is available for download from my website http://www.dactyltech.co.za.