Friday, 12 March 2010

Shine On Harvest Moon

As part of my long term commitment to the owner of Harvest, my last task in the Harvest ECO boat project is to get the remote control installed and working.

Back in 2005, as an interesting theoretical challenge, I started designing Harvest with Paul.

The design brief was that the boat would be capable of being remote controlled.

In 2007, the agreement was made that no money would change hands, but I would be allowed to publish details of the project on the Just Canals forum, in exchange for my efforts.

The main problem is that everything was purchased in 2006 and has been sitting around on the boat ever since.

Luckily, I tend to keep copious notes and drawings.

The batteries in the remote control (transmitter) have been discharged for four years and Paul, the boat owner, couldn't find the key for the switch which is needed to switch it on.

No problem.

I managed to hot-wire the key switch and put the batteries on charge.

There are basically 3 steps to full remote control:

1. Bow Thruster
2. Propulsion
3. Rudder Steering

Paul is still busy getting the hydraulics bled and sorted, so we elected to leave the rudder steering for another day.

So, I installed the receiver unit to the 24VDC supply and got that to power up. The receiver was then connected to the thruster panel first. 

We had a little debate about whether the thruster arrows should indicate thrust or boat direction, but in the end, agreed to mimic the set-up on the hard wired control panel.

When all was powered up, it was quite amazing to stand on the towpath next to a securely moored boat, press the thruster buttons on the yellow transmitter box and watch the bow surge against its tethers.

The system appears to be quite safe. If the radio signal drops out or one of the buttons malfunctions, a microprocessor in the receiver unit senses this and drops an interlock relay so that nothing moves.

This was inadvertently tested because we have a teething problem with either the power of the transmitter or the aerial location.

The receiving aerial is currently inside the console and cannot stay there. Also, we are not sure if the rechargeable batteries are goosed as they have been sitting around for so long.

When you start to walk away down the towpath from the wheelhouse, the radio link is lost after about 3-4 metres. 

The contactor drops out in the receiver and all control is switched off so everything stops.

On my next visit, I will have to replace the batteries and try to rig up a remote aerial that can be seen at all times, in order to maintain the "line of sight" contact needed by radio systems.

Before I left the boat, I also managed to interface the remote control to the electrical propulsion.

So thats two out of three - to be continued....

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