A couple of days ago, JBkiwi commented that the dinghy was "fully loaded" so I decided to weigh it again.

The original plan for a full size version of the dinghy quotes a fully loaded weight of 700kgs. At 1/6th scale that equates to a target of 3.24kgs. Last time I weighed it, it came in at less than 3Kgs. Now everything is installed, the total weight is 4.2Kgs.Somewhat over the target weight, but it looks fine on the water. (I knew Ben needed to loose some weight !😂)

Now that everything is installed, I've included a photo showing all the internal fittings. Access to everything is relatively straightforward as it is all spread out flat, under the floorboards. The maximum clearance under the floor is 30mm and much less than that under most of it.

No, not the RC gear, but Bill and Ben's on-board entertainment system. 😆

The original installation used an FM radio and 22mm speaker hidden below the floorboards of the dinghy. Control from a switched channel on the Transmitter allowed it to be turned on/off, tuned to different stations and the volume to be adjusted. It worked well in the workshop but was not effective out on the lake. It was difficult to hear and difficult to control. So, time for an upgrade.

The first issue to address was the speaker. There is no room under the floorboards for a larger speaker, but with a bit of thought I was able to fit a decent sized speaker under the foredeck. The speaker is mounted on a plywood panel which can be juggled into place past the forward frame. A block of foam rubber under the foredeck presses on the back of the speaker and holds the ply mount up against the frame. With this upgrade there was enough volume to hear the radio out on the lake.

However, many of the radio stations were barely audible owing to poor reception caused by the FM aerial also being below the floorboards. This meant that the aerial was at or below the water level. Not a good position for an aerial 🤔 There wasn't a simple solution to this one, as I didn't want anything sticking up in the air. I did consider adapting the fishing rod, but decided against it. Finally, the radio doesn't retain it's settings when switched off which compounded the difficulties by requiring the radio to be tuned in each time it was switched on.

Time for a rethink. RobBob suggested an MP3 player. I had been looking at these devices for a while, with a view to building a sound unit for the Crash Tender, so time to give it a try. These tiny units are widely available, at very modest cost. The part number is WTV020-16. Putting that into Google will bring up lots of vendors. They are often described as MP3 players, which they are not! What is meant by that description is that they have controls for on/off, next/previous track and volume up/down like an MP3 player (which they don't). They do not play MP3 audio files. They play audio files in an ADPCM format known as .AD4. Fortunately, it is easy to convert MP3 or WAV files into the AD4 format using a free downloaded application on the PC The audio files are stored on a micro SD card which can be loaded from the PC.

The documentation available for these players is very poor. That is compounded by having several different types of these players available which work in different ways and it isn't always clear which one is being offered for sale. They are specified to operate from a 3.3V supply, although mine needs 3.45V to get it going! After many hours of frustration, and one fried micro SD card, I finally got it to work. Having got it working, it has so far been very reliable and simple to operate.

It connects directly to the speaker and has an adequate volume level without the need for a separate amplifier. An RC switch with three outputs allows selection of next/previous track and on/off. The volume up/down inputs don't work as described in the documentation, but that hasn't been a problem.

The end result is that Bill and Ben now have a selection of Sea Shanties to listen to while out on the lake. 👍😊

Having completed Ben's surgery, it's time to bring him to 'life' 😂

There are 5 items to control, three servos for his head, arm and body movement plus two switched channels for the e-cig smoke generator and the air pump. Whilst in theory all this could be controlled from separate channels on the Transmitter, it would be beyond my manual dexterity to control it all at once and produce any sort of realistic actions, not forgetting there are already two channels in use to control Bill's rowing. So, Ben needed a brain.🤓

The block diagram gives a high level overview. Ben's brain is an 8pin PIC microprocessor. It has a single input from the receiver, and five outputs to control his actions. The single input is driven from a switched channel on the Transmitter. A single quick flick of the transmitter switch triggers him into action.

Once triggered, Ben's brain follows a series of simple steps defined in a lookup table. An example is shown in the photo. The delay column defines how long Ben is to pause for (in 0.1sec increments) at various points in the sequence. The three servo columns define where the servos are to go to at each step. The numbers in the columns relate to servo pulse widths. A value of 20 equates to a servo pulse width of 1mS. A value of 120 gives a pulse width of 2mS. Thus values in the range 20 to 120 will give the full range of movement for each servo. The last two columns simply define when the e-cig coil and the air pump should be turned on or off.
Once his brain reaches the end of the table it stops and waits for another trigger from the Transmitter.

The video clip corresponds to the movements/actions defined in the table provided, so if you have time to spare, you can follow the table steps while watching the video.🙄

The e-cig and air pump signals from the 'brain' connect to the coil and pump driver. This driver provides separate PWM signals to the coil and pump to drive them at a reasonable power.

A separate table, which can be selected when switching the dinghy on, puts Ben into 'fishing' mode rather than 'smoking'.

I hope this might help anyone thinking of trying something similar, perhaps using an Arduino to control gun turrets, winches etc.

The smoke generator is based on experiments I did earlier this year with JBkiwi.

An e-cig mouthpiece was modified by making a polycarbonate plug which fits the end of the e-cig in place of the normal e-cig battery. This plug enables connections to be made to the e-cig coil as well as providing an air inlet from the air pump. With the e-cig coil powered up, the air pump pushes air through the e-cig and out through the mouthpiece.

The smoke liquid is glycerine diluted to approximately 25% water/75% glycerine. I found that some of the smoke liquid can escape the e-cig and travel down the exit tube. This is especially the case as the e-cig reservoir gets close to empty. As the tube which runs up to Ben's mouth is only 1.5mm ID this liquid caused some problems with blockages. A 'smoke dryer' was added to the outlet tube to solve this problem. It comprises a small circular container made from acrylic with an inlet and outlet tube. The internal space is divided into two by a fine stainless mesh which runs across the centre diagonal. The mesh catches any liquid in the smoke which then collects at the bottom of the container. It needs to be emptied between outings.

The second photo shows the smoke generator installed in the dinghy. The battery was originally installed symetrically either side of the keel but has now been moved to the starboard side of the hull to offset Ben's weight on the port side and maintain an overall even keel. This made some room for the smoker components.

Work on Ben started by building a mock-up of the stern of the dinghy so that I could sort out his position, seat height etc.

Ben, just like his older brother Bill, is a modified Action Man. These are readily available second hand on internet auction sites at low cost provided you are not trying to buy one of the early 'vintage' models. They are made from very thick plastic which makes them durable, but heavy.

Using a cutting wheel in my Dremel, the first step was to remove the head by cutting through the neck. This was followed by splitting the body front and rear. A piece of 0.8mm brass sheet was cut to the shape of the body and then trimmed/drilled and extra pieces silver soldered in place to fit the servos until it ended up as you can see in the photo. There was no drawing for this, it just evolved bit by bit as I worked out how to fit everything in.

There are three servos inside the body, the first rotates the body on a pivot epoxied into Ben's hips. The second servo is mounted on the back of the brass plate and is connected to the left arm with a pushrod so that the arm can be raised and lowered. The head is mounted on third servo at the top of the brass 'skeleton'. Unfortunately, there wasn't enough room to animate the right arm.

Once the mountings for the servos were complete, extra holes were drilled in the brass plate wherever possible to reduce the weight. Ben's arms and legs were also drilled to reduce the weight. As Ben sits at the stern of the dinghy, and to one side, I was concerned about his weight causing problems for Bill when rowing. Drilling all the holes reduced the total weight by over 50g.

The pipe was carved from a length of hardwood. It has a small magnet let in to the side of the bowl which attaches to a corresponding magnet set into Ben's palm. I don't want him dropping his pipe in the lake 😊. The smoke is carried by a small bore silicone tube which runs up the back of Bens body. It connects to a copper tube soldered to the head mounting plate attached to the head servo. The smoke travels up through the neck into the head and out through a series of small holes drilled between the lips. There is no smoke from the pipe itself, although this is barely noticeable in practice.

Ben's head was sent off to the same 'reflocker' as used for Bill. He did an excellent job on it. The moustache hides the holes in the mouth.

The smoke is generated from an e-cig mounted under the flooring of the dinghy. More on this in the next post.

Bill’s younger brother Ben had his first outing today.

Philcaretaker has put this excellent video together and posted it in the Media Gallery. I’ve copied the link here to keep it with the rest of the blog.

Thanks Phil 👍👍

Graham93

With the recent relaxation of Covid19 lockdown rules, Bill's younger brother Ben came to visit. 😂

Details of Ben's bionic surgery to follow later.

(Apologies for the poor quality of the video - not enough light)

Having provided Bill with a radio in the dinghy, I thought it would be fun to make it work.

A search of the Web turned up an FM radio kit for £1.50 plus £1 postage. I don't understand how they can make these for so little. It included a battery holder for 2 AA batteries, a headphone jack, and five pushbuttons for controlling the tuning, volume and on/off. I didn't use any of these items, so they are now in my spares box in case they come in useful in the future. The remaining components were mounted onto the circuit board.

Bill isn't able to control the radio in the dinghy as he has his hands full with the oars 😉, so I decided I would have to do it for him remotely. An RC switch with 5 outputs was built using a PIC microprocessor. This is controlled from the three position toggle switch on my FlySky Tx using the pulse counting technique.
Switch up and hold, tunes the radio frequency up.
Switch down and hold tunes the radio frequency down
Switch up, centre, up and hold increases the volume
Switch down, centre, down and hold reduces the volume
Switch up, centre, up, centre, up and hold turns the radio on or off

Although larger, an Arduino could be used to provide this sort of functionality.

Also on the RC switch circuit board is a 3.3v BEC to power the radio and an audio amplifier.

The speaker is 22mm diameter. Unmounted there is little sound to be heard from it so I mounted it into one end of a 25mm acrylic tube. The tube is filled with cotton wool and the other end sealed off with an acrylic disc. The volume that can be achieved is quite surprising for such a small speaker and while the quality of the sound isn't great, it is only intended to provide low level background sound.

Having returned to the hobby last year and with lockdown this year, I haven't had many opportunities to visit model boat shows. However, when I have been to a show, I always felt that the models on display that were 'doing something' were the most interesting. Lights on, smoke from the funnel, rotating radars, etc just help to bring the model to life. I have thought about how to achieve this with my Crash Tender, but with a standard receiver with 10 separate channel outputs it isn't easy. However, the rowing boat is a different proposition.

The rowing boat uses a receiver with a single PPM output rather than the usual separate PWM outputs to individual servos. The PPM signal is carried on a single wire between the receiver and the rowing controller. There are eight channels carried as a series of sequential timing pulses along the single wire. Only three channels are currently used for the rowing boat, speed, turning and head movement.

I have put together a PIC based 'demo adapter' which fits between the receiver and the rowing controller. When the rowing boat is switched on, the adapter checks for a PPM signal from the receiver. If the signal is present, indicating that the transmitter is switched on, then the adapter goes into idle mode and simply lets the receiver signal pass to the rowing controller as normal. However, if no signal is detected from the receiver, (i.e. transmitter switched off) then the adapter takes over and sends a PPM signal to the controller. A lookup table in the adapter adjusts the PPM signal over time to simulate changes in transmitter stick positions, hence operating the dinghy as though it was being remotely controlled.

The video shows the boat being switched on using the magnetic on/off switch, with the transmitter off. After a few seconds, Bionic Bill starts rowing, turning and looking left and right. The program runs for about 3 minutes, and then loops back to the start and repeats.

If I ever get the opportunity to take Bill to a show, I can simply leave him on the bench to row all day.

Following suggestions from Colin, and from Doug, I took pity on Bionic Bill and made him some lunch before his next trip out.

The flask is made from a short length of 12mm acrylic tube and bits of plasticard. The 'sandwiches' are a block of wood wrapped in foil - sorry Bill, not very tasty 🤣.

The bottle was a challenge. I hadn't been able to find one at the right scale, so used another piece of acrylic tube. One end was plugged with a length of acrylic rod and then turned on the lathe to produce the bottle neck. The bottle was then part filled with alcohol from the base before a piece of clear acrylic was glued on to seal it. The full sized bottle label was photographed and reduced to 1/6th scale before printing onto a self adhesive label.

Apples were moulded from 'polymorph' - a plastic which becomes like plasticene when heated but sets hard when cooled. (Useful for making moulds).

I considered making a cool box, but decided a wooden crate would look better, and was easier to make.

While I was making lunch, I also decided to spoil Bill and give him a radio to row by. Made from plasticard based on a 'Roberts' design, with a photographically reduced control panel. The telescopic aerial is brass tubing in two diameters. It doesn't actually work ...... yet 😁