RC Tank Warfare community hobby forum

Thanks Midlife!

Did a bit of modding today. Received a TARR III smoker for RC tanks, etc. Consists of a few diodes and a 7805 voltage regulator , a DC 5v fan, a cast metal box, and a plug to go into Heng Long smoke control RX18 or similar.

But the smoke output was minimal. Not enough current to the heating resistor. However, 3 amps supplied by the TCB should be enough to get a small coil hot. So I tested a spare Burn Effect V3 coil. Sure enough, got hot enough to make much smoke. The power transistor on the TCB did not get hot, but the power wires did warm up a bit.

So next plan, mod the system. Using throttle forward ESC output 1 on the TCB to burn effect esc control module. Then to the heating element. The fan switches on and off via the TCB 'Smoke' plug. The fan speed is controlled by the 7805. 3D printed a mount for the heating coil and put her all back together. Works like a champ. Fairly decent proportional control of the 5V fan. However, the coil only heats up in forward. No big deal as it makes much smoke.

dgm. is of the control board for fan speed. NOTE: I had to use the positive out on channel 1 off the TCB to power the burn effect smoker board. It does not run off the esc. That means middle red wire is connected at the servo out on the TCB. However, on the other end, where the signal passes through the burn effect board, the ESC red wire is obviously disconnected. see pic of messy wiring.

Vid:
https://www.youtube.com/watch?v=W_K2Q_FW-Vw

It was bothering me to have an easy problem unsolved. Power to smoker problem is now solved (temporarily I was using 5v off TCB servo out). However, I could not turn off the smoker board using the 'smoker OFF' switch in the OPConfig. Only the fan turned off due to my hacking of the smoker/fan unit.

Using a 3906 transistor and 18k resistor, I tapped into the power from the TCB at the smoker (currently 7.4v) and using the smoker on-off ground, I am able to power the burn effect board on and off , at same time as the fan, using a single radio Tx switch. I thought that I had to decrease voltage to the burn effect board to 5-6v to make all components happy , but I did not. And I now at 7.4v, I have smoke in reverse. I am guessing that the smoker control board needs at least 6v to work well.

The reason I could not use one of the other TCB switchable power ports is that there is that there is no ground 'out' on the burn effect board, so I could not close the 'load' loop. I could tap into the 5v supplied throughout the TCB ports for 5v if needed. And I could configure say a 'secondary' light port to activate ground at same time and with same trigger source and same trigger action. But I am still left with only a 'ground' turning on or off, while the smoker board requires 'power' turned on or off. Power remains constant at these spare ports, so I needed to build the 'grounding' trigger with a 3906 transistor, which then supplies power to the burn effect board when ground in activated through really any TCB port I choose. I chose the smoker port because it makes sense.

I did run a test with the second light port on the TCB. Nice regulated 5v. But not enough to run the Burn Effect board in reverse for some reason. Back to 7.4v off the smoker tap and all is well again.

Or, you could just run a 5v relay off the TCB aux port to power the burn effect board, and then configure TCB aux out to switch on and off with the smoker and forget the whole transistor/resistor thing, but where's the fun in that?

Hehe, you lost me after thanks Midlife lol
Oh how I wish I understood electronics
Cheers
Wayne


Sent from my iPhone using Tapatalk

Nice work xrad, I'm glad to see the TCB starting to pick up in popularity. It's a great board, and so flexible too.

With regards to the smoker, I'm not sure that Tarr's quality control (or maybe inventory control) is what it should be. I've had a Mk1 Tarr that was supposed to run off the 7.4 V from the battery that needed to be stepped up to 11 V before I got any smoke out of it, and I had a Mk1 12V that was supposed to run off 12 V but would melt its solder joints when it was run above 7.4 V. I have separated the fan and heater element off both of them, and run the heater element directly off the battery so the board controls the fan only. That way the smoke output is still proportional but doesn't struggle at lower engine power or at startup.

Food for thought, might save you some trouble with the additional circuit; especially since that looks like it's for a standard Heng Long smoker on a stock RX18. You shouldn't need the diodes (since the TCB can control proportionality without splicing it through the motors), and I assume that voltage regulator is unnecessary since you're using a fan and not a pump.

Good idea about running the fan directly off the TCB! Did you use one of the low amp motor drivers? What is your set-up? If I alter the 'heng long' plug on TCB to a modulated power supply, I will lose the current 'on-off' function, and therefore lose the 'on-off' function of the current smoker set-up. Unless I find another 7.4v capable ground on the TCB (maybe one of the motor drivers? will have to research some more.

The diodes are only for running the fan off the motors. If I run off the TCB, the voltage regulator 7805 on the fan could then be eliminated. This whole circuit would be unnecessary using a TCB control function. However, the fan seems more proportional with the 7805 . I may try to go directly to 7.4v and forget the fan voltage regulator.

The Burn effect board needs 7.4 v and runs off the 'Heng Long' plug on the TCB. This supplies full battery voltage from the battery 'in' on the TCB. I know this because you can run power into the TCB if you plug battery power into the 'HL' smoker plug(oops).

Agree about TARR quality. Lacking. poor solder connections and poor wire quality. But the price of the metal box and the diodes, transistor, and the fan would have cost me ~20$ anyway.

The Ferdinand is a menacing vehicle. Great to see you pushing it forward. It will bi interesting to see how you deal with the gun assembly.

xrad wrote:Good idea about running the fan directly off the TCB! Did you use one of the low amp motor drivers? What is your set-up? If I alter the 'heng long' plug on TCB to a modulated power supply, I will lose the current 'on-off' function, and therefore lose the 'on-off' function of the current smoker set-up. Unless I find another 7.4v capable ground on the TCB (maybe one of the motor drivers? will have to research some more.

I haven't set got my TCB installed yet, but I had the Tarrs set up like that on both an IBU2 and Elmod. The fan is/was plugged into the smoker port on the control board, while the heater element is wired directly to the battery through a simple switch. It's probably not the best for battery life, but I haven't run them long enough for it to be an issue. Yet!

xrad wrote:Agree about TARR quality. Lacking. poor solder connections and poor wire quality. But the price of the metal box and the diodes, transistor, and the fan would have cost me ~20$ anyway.

Yeah, definitely. I'll still buy more of them, they're better than the Heng Long units by a long shot!

Question, I read on forebears site? that the power cable for the heater should be in line with the motor power cable for the proportional production of smoke. Would this be the same as in your choice?

Hi Soren, You could do it that way, but you lose fan modulation (speed control) if TCB set to smoker ON or OFF . But you would probably just be turning the coil ON/OFF via the motor power. Not a good method. Best to run the coil off it's own battery power. Or, you could modulate the smoker via the OPConfig, through the smoker port on the TCB. http://openpanzer.org/wiki/doku.php?id= ... all:smoker

I have to run my smoker coil at a different voltage than supplied with the TCB, and with a different controller. the the nice thing about the burn effect separate control board is that there is an easy analog adjustment to set smoker function on/off point and it has a very important 9 sec latch, then times out so that I do not over heat the coil.

The fan is not really an issue as it can be run off the motor power wires or via the TCB on a separate aux port. I just get the best speed modulation of the 5v brushless motor with my current set-up. I am trying to find a way to better modulate fan speed to follow throttle via the TCB smoker at 7.4v, and then route the ground switch of the burn effect board to another aux channel negative on the TCB.

Raminator, maybe I just got a dud unit from TARR.

Ok, got the wiring sorted. Eliminated the 5v 7805 regulator. Not needed when my max V is 7.4v, and allows better modulation of fan speed. I kept the 6 diodes as the fan still will run off L+R motor power supply. Keep the 3906 transistor switch and resistor to operate the smoker board.

I redesigned a baffled inlet duct for a smaller 5v DC brushless motor. The new one has a 15 mm or so fan diameter. I was getting blow back from the bigger fan and shorter inlet duct even with a single baffle(in addition to the small outlet tubes). The smoke fluid was gumming up the fan. So now a new double baffle taller inlet and lower intake pressure and all seems well. Here is the final version of the new RC smoker for the Elefant.

Might be a bit too much smoke!!
https://www.youtube.com/watch?v=UCVbqiFf070