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Simple Smoke Generator

In discussion with jbkiwi, we felt it would be a good idea to bring together into one post the different smoker experiments we have each conducted to make them easier to find for anyone interested in having a go. Here is a summary of my experiments. JB will add his in time. My implementation is based on an e-cig H2 atomizer. These are readily available at low cost. The unit as purchased comprises a 2ml tank, heating coil, and a coupling which would normally connect to the e-cig electronics/battery. I made a simple end cap from acrylic which is a push fit into the coupling. Any insulating material could be used for this, even a piece of hardwood could be carved to shape. The end cap is held in place with a couple of small screws through the side of the coupling. Before fitting, it was smeared with silicone sealant to ensure an airtight seal. A central screw in the endcap can be adjusted to make electrical contact with the coil. The other contact to the coil is via the body of the coupling, using one of the endcap retaining screws. A brass tube fitted through the side of the endcap allows air to be pushed through the atomizer. For installation in my Crash Tender, I increased the capacity of the smoke fluid tank by adding an additional tank around the outside of the original atomizer tank. The smoker fluid I use is 3:1 glycerine:water. The coil seems to work best when energised with around 5 watts of power. This can be achieved by using a DC-DC converer to drop the battery voltage to around 3volts. Simple low cost buck converters are available on-line. As an alternative, a PWM electronic circuit can be used to power the coil direct from the battery voltage, provided the power to the coil does not greatly exceed 5w. I found to my cost that feeding 25w of power into the coil (circuit error!) vaporises the coil in the blink of an eye! Fortunately, replacement coils are readily available. The exposed metalwork of the atomizer typically reaches a temperature of 30 -35C while it is running but that depends on how much power you feed into it.😉 The air pump is not critical. I have tried a couple of different types and the both work well. It is useful to be able to adjust the pump speed, and hence the volume of air being pushed through the atomizer. Small motor are easily obtainable. The atomizer works best mounted in a horizontal position. if mounted vertically, as shown in part of the video, it has a tendancy to flood the coil. By adjusting the pump speed and the coil power a range of different effects are possible. The video shows several examples of different settings. It is possible to generate just a gentle waft of smoke suitable for a funnel on a tug or a quick pulse of thick smoke possibly suitable to simulate gunfire on a destroyer. For my Crash Tender I mix pulsed smoke with water using a venturi type connector and then feed the resulting mix out through the exhaust ports. More details of the installation in the Crash Tender can be found in my Crash Tender Refit blog. Happy to try an answer any questions. Graham93

4 years ago by Graham93

Response

Re: Exhaust Smoker

Hi Michael, Thanks, glad you like it.👍 Re: Is the electronic controller based on PIC microchips a commercially available item? The controller is my design based on three baseline PIC microchips. Not the most elegant of designs, as this could all be implemented in one mid range PIC with a bit more effort, but it was quick to do this way, and I have a stock of the baseline parts. PIC1 acts as a simple RCswitch monitoring the throttle channel to turn the smoker on/off. PIC2 provides the smoke pulses by turning the air pump on/off at a rate determined by the throttle channel. PIC3 implements two motor , one for the water pump, and one for the air pump. This latter speed controller is modulated by the on/off pulses from PIC2. The circuit board shows the three PICs. On the underside of the board there are three surface mount power FETs to drive the smoker coil and the two pumps. I'm happy to share more details on my current implementation of this, but it is not very configurable/transferrable unless you have experience with PICs and the necessary tools. For example, following the trial on the lake yesterday, I think it would work better if the water pump was running a bit faster. To make that happen I have to change some values in the software, and then reprogram the appropriate PIC. It was just easier to put together this way, but its not very practical on the lake.🙄 I have it in mind to redevelop the software on a better PIC and to add some buttons on the circuit board so that various parameters could be adjusted without having to reprogram the PICs. It will be an interesting challenge, but will take a little while as I'll have to fit it in around everything else 😉. Graham93

5 years ago by Graham93

Forum

Mtronics ESC's

I have used these for many years and never had a problem. Just recently there seems to be a few now that have burnt out or have just gone pop. I am wondering if there has been a change in the manufacturing process. It could be a good question to ask them! Martin555.

5 years ago by Martin555

Forum

Electronics 43x esc

Hi. These are really excellent quality and can handle a high degree of voltage and amps. I use two in my vosper which each handle 24 volts. Be warned though you can seriously damage them if you reverse the polarity when connecting to the battery. There are two adjustments on them. I think one is sensitivity around the low speed response which improves greater low speed control. The other is speed range which gives you adjustment on the range of speed in relation to your radio stick throw. I have found these to be excellent high quality controllers giving excellent service and performance. You can wire in an anti reverse polarity circuit using a diode which is described in the instructions. Regards Kevin

5 years ago by kevinsharpe

Forum

Fairmile c class maiden voyage

hi there Chewi having read through your postings and watching your video - I am not sure if you have the ACTion P94 set up correctly. You should be able to spin that model round on the spot as the P94 contains a rudder motor mixer built into it. However, be warned, the P94 doesnt like certain 2.4 transmitter sets. Basically, you have to set your transmitter back to zero manufacture settings with no mixing at all on your transmitter to get it working - and - its all done in the ESC - I have built several triple screw vessels myself - the RAF63and the MTBs and basically what I used to do there is use the old Electronize from the 90s which dont have the pre-programmed chips in them so that I could switch the signal on and off to the speed controller, thus allowing me to control the centre prop by switching the signal off and on. So, when I wanted speed I ran on all 3 props but when I wanted to manouvre I switched the centre prop off and allowed the 2 outboard motors to spin the vessel with the rudders, using mixers. In this particular model - I would ditch the gelcel battery and go for a Ni-MH battery and the 9.6 volt 500 mAh - 3 of these batteries one for each motor should give you ample run time. John

5 years ago by JOHN

Forum

What batteries?

HI all, I am building a 1/24th Perkasa wooden kit. And I have no idea how to power it. I have bought two Graupner Speed 700BB turbos that run from 9.6v to 12v. I don't want to use a 12v gel battery as the boat will sail like a brick! I want to use two coupled 50 amp with Lipos, but I dont think I can use them with these controllers as they are for brushed motors and have a bec 5v / 1amp which I think would destroy the Lipo. What size Nimh battery pack would you recommend, and would I need two packs or would one pack be enough. I have other boats that only have one motor and are smaller than this one so have not had this sort of conundrum! I am on a limited budget so cant afford to waste money on trial and error combinations. I would be very grateful for any suggestions.😭

5 years ago by Daveyboy