Model Boat Mayhem
Technical, Techniques, Hints, and Tips => DC Motors (Brushed) and Speed Controllers => Topic started by: rathikrishna on December 21, 2010, 05:34:38 am
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Good morning Friends..when i was started to make RC crafts in all means,the speed controller was my ever nightmare.at begining i was using a simple on and go type controls like any cheaper RC cars.but as i progress i started to use my knowledge in electronics to my applications. as a result i made several types of speed controllers still working nicely after years of gruelling service.i am posting this article here because i know many of my friends are need it..when i asked for a speed controller here at Chennai Town,they gave me a price list.and was
shocking while looking in to it.for a single channel speed controller, the price was Rs 4500/00-!!!! (a Dollar is 45 Rupees now)..with that money,i can buy a good quality DVD player, or a 20 inch CTV, or a Dual Core Mother board, or a good digital camera.!!!!...
So again..see the instructional video here....http://www.youtube.com/watch?v=SS3gkDgQSz4
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and if you ask for a two channeled one its 6000/00-almost...and for a motor differential one..9000/00..ohhhh...and can only work as the home made one..so i decided to make my controllers even better than before.now all it works nicely and flawlessly...
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to make a good quality solid state speed controller, you need heavy and expensive equipents and ample of money and ultimately a good knowledge in electronics..? sure..? rethink..NOOOO....you need nothing, but some patience and mechanical mind with some time to spend. here we are...you need only some handy things from around you...and sure a soldering iron in to 25 watt, a three pinned one to avoid leakage. soldering flux and good solder wire.you need not even a multi meter !!!!!!!...
first of all find a sliding or rotating type volume controller can found at scrapyards or can buy at any electronics shop within half a dollar.if you are taking it from an old source the value of the potentio meter is not an issue...any value will work.so if you are buying one try to get it within 50 Kilo Ohms, and Linear type one.if you are using a conventional servo, the sliding one wll be the best bet.and if you are using a toy RC a rotating type will be best.but you can use either for either use.
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i took this old tape recorder main board to take needed parts to me.here you can see some good sliding controller looking at me.."hey Rachu we are waiting for you"...hi..hi..
desolder it from base carefully...now its free...now we got the main part of the controller..the variable resistor, or a potentio meter...its value here is 50 Kilo Ohms.
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now we need a power transistor to drive our motors, lights, or anything you need...here some inexpesive but ever classic silicon, and Germanium transistors, from, MJE 3055 up to 2 Amps..TIP 3055 up to 5 Amps..and 2N 3055 for 30 Amps or more as you can bridge it. the TIP 3055 also can be used instead of 2N 3055 to save space. you can place these or this transistor anywere you like so you can save space and weight.and a heatsink is a must for higher amps.no fan is needed to cool it as most of these PTs can withstand temperature up to 180 degree of heat..
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and here you have a second alternate for PT, is Darlington pairs..means two transistors in one..with this you can achieve a good soft start and stop..good for light crafts..
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now its fixed and wired..you can see how simple it is..here i have wired it in a rough way..but you can simply place and wire neatly as you can...so everything will be tidy..a 470 ohms resistor is used with controller to protect the transistors from stalling current,when a stalling of motor occurs.as the TIP 3055 is employs a thermal protection inside you need not worry about burning it out while a short circuit happens...no worry...reverse polarity is not a matter here as we use a diode in series with this circuits.there is nothing to go wrong
with it so you need not worry about splashes of water..if this goes to water nothing happen..wait untill dry..and then works again..no money loss...
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now i glued a piece of aluminium sheet on to the arm of servo, with many holes on it to adjust the stroke length of the actuating arm,as we need...
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Make a hole at the tip of the controller..carefully..dont tear it....
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now yo can simply fix it as shown,all with foam boards,because it can absorb excess throw and shock,made out of servo if you switched of the transmitter first...no steel or plastic structure is needed...i used a brass rod here..its only for a guidance..you can simply do on your way with your own ideas...
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now our controller is ready for the ordeal..but still lack one thing..a reverse switch..here i used a DPDT switch, can foud any land phones, or can buy at any electronics shops..much cheaper..here it costs only a 5 Rupees..(45 Rupees a Dollar).
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now wire a second line in reverse with wires from transitor out..and place the switch at the neutral position of the arm, after checking the play of servo arm..place the main throttle stick at this position as neutral...mark it or keep it in mind..
Now its ready...with a motor..this motor was actualy a toy motor, for 3 volts..and i reworked on it for 9 volts and 700 ma..and in to 6000 Rpm..for my KAAKKA..means the Raven,from strw board and bamboo sticks..a flying model of my own..have to compleate it..
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And here i am adding some useful proven circuits , all tested and with me now,is first one is simple but effective inexpensive but works almost same as professional one.its much simpler , and using the ever basic principle of transistor biasing.here the base voltage is controlled via a variable resistor, our volume controler in this case,so the out put will remain as constant untill we alters the base voltage.
Second one is based on MOSFET( Metal oxide semiconductor field effect transistor),for greater amperage handling.you can simply fix a RS 500 or more powerfull motor to it.if feel bad can bridge same one with exsisting one so it will handle your load nicely.here you can see that the circuit is more complicated, because this unit is based on PWM, or pulse width modulation. so it may generate some SAW, (Surface Accoustic waves)means some radio disturbances, so we must use good quality wires, and must use a shielded wire to connect
the variable resistor.
Third one is even more complicated because here we are using a CMOS Ic for making pulse.(Complimentary Metal Oxide semiconductor).the Ic is easily available, and cheap.
The next circuit is based on Darlington Pair transistor means two PTs in one.here is the circuit. its too easy to make and an ameter is connected in series to output, so you can simply determine the load current in output.this circuit is meant for only under 2 Amps.you can also use this circuit as a battery charger and voltage eliminator for electronics service...its based on BD679, a cheap PT to buy.
so..now its on the way..woooommmmm....try it...and you can save ample of money...and you can do many other things with those saved money...the main job that to do is...buying some good ice creams for me...and send me...hi..hi...ommm yummy..yummy...
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you can see a red marked potentiometer in all circuits, is meant to fix on the servo...you can also try with various value in the first basic circuit, from 470 Ohms, to 1 Meg Ohms, and can get various results with your SC. and one main thing is to remember that, all speed controllers consume some voltage itself..here in the basic circuit, the PT will drop a .7 volts as its junction barrier current. we cant eliminate this here as we need a brake or stop to our used motor. so if you need a 6 volts output, you must connect a 7.2 volt battery pack to the circuit.so it will work nicely...so try it...save money...and never forget to give some icecreams to me....ha..hi...so have a nice day...Merry Christmas...Happy new year...this New year may a good year to you all...with this speed controller...
Any suggestions , corrections and advice will be great , for this article, so we can simply upgrade our speed controller to a even more great extent...and i will post a MOTOR DIFFERENTIAL CONTROL, means controlling two motors with to servos as FWD, REV, LEFT, RIGHT,while first moor spins at CLOCKWISE, while second one is to ANTI CLOCKWISE...so we can control our crafts even more simply....
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hi rashi, (SUPERWOMEN) this is fantastic what you have shown many thanks,
i will try this in the new year, merry xmas
davidj
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Onw word Rathi BRILLIANT!!!!!!!
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Stunning. You are a genius, to come up with such gear from old stuff just lying around. Brilliant.. :-)) :-))
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Thank you all...but you must try such things yourself..its only a simple idea..and all you can make even better things..because making a craft from own idea will be more satisfying..indeed..and i know all you are veterans by all means..thanks once again..
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Hi Rathi, love to see these circuits, I used to use them and they are very satisfying to operate as you have made them yourself. Still have a small pilr of 2N3055's etc. I would make my own battery chargers etc.
I then got lazy although I would build from published circuits, but soon the technology started to pass me by. With surface mount and proms etc.
Still like to put a circuit together though, although I now need the magnifying glass to get to some of the small stuff.
Do you have vero board available?
I also used to use a small construction board where you can plug in integrated circuits and then do a try out of a circuit by plugging in the components and seeing if it worked.
Carry on the good work,
many regards Roy
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Hai Roy..all we know electronic, components are shrinking a lots now..and its so superb..sure..but here we can see all used components are big enough to se with naked eye..and very inexpensive to buy..if i buy all things from shop here, i can simply buy all components with a money of a cup of coffee with two cutlets.and all it works for a lifetime. and more satisfying..we know again, if any SMD, or COB accidentally drops on water...!!! it will be a mess but here nothing will happen..i have veroboards with me and bread boards..but no usage..i always make my own PCB s by chemical etching...thanks for the interest in this article..i hope i can expect a good posting from you, so many of our friends will arise from the laziness...and never forget to send me some icecreams with saved money...hi...hi...
Roy..we know we can also use these circuit to dim and bright a light source...or can change the pitch of a horn...so never be lazy...please post usefull circuits and goodies here..we all are waiting for such innovations...with great hope...rachu.
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Just outta curiosity how much amperage can one of these home made esc's actually cope with?
Its a great idea making one with the parts you have but the motor you have been using have been on the small size compared to some that we have available here.
What suggestions would you have, to say build an esc that can can support up to 20A's since this is the typical size most 'regularly' use here, or is the esc the mechanical type that can support anything you throw at it?
When it comes to esc mechanics i have no clue. I have always purchased mine with little regard for they construction.
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Friend..we can get all details about the parameters of used components at an electronics shop, or from the DATA MANUAL..i will post a video for your question...to night...i have tested my basic (shown) circuit with 30 amps load, along with a bigger heatsink, and a small fan from an old grapix card...only thing that we have to listen is the gauge of the wire...and if you are too nervous about your circuit, you can simply add on this circuit..that i will post tomorrow, as i do not have with me now..i am not at home now..but in a cafe..sure i will post the new video with a big motor, and short circuit protection.
The over load and short circuit protector can be made easily by two methods.one of the ever simplest possible method is using a thermistor.we can fix a thermistor on the heat sink of the PT, so it will acts as a sensor.you can decide it as PTC or NTC. and can simply wire accordance.basically its function is controlling the base bias of the given transistor, so the output.we can simply alter it again with simple PCB PRESET.so wait until tomorrow...i have to shoot the video tonight..after my parents sleep..sure..good night..
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Topic name changed...... shortened :-)
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very good and well explained
John
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Rathi,
Are there no limits to your talents?!!
Mike
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Good morning ..and Thank you ,Respected Administrator...here is the answer for the question from Roadrunner...here we are back...i do not have any much good power motor with me.i have, but still all reworked by me..so, there must be a problem of belief..so for you, i dismantelled my drill, for motor, and you can see here.
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Good morning ..and Thank you ,Respected Administrator...here is the answer for the question from Roadrunner...here we are back...i do not have any much good power motor with me.i have, but still all reworked by me..so, there must be a problem of belief..so for you, i dismantelled my drill, for motor, and you can see here.
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Oh..sorry i lost my connection at cafe..now 15 more kms away to answer you..back again...here you can see its motor, its number is RS 550..and named as JUNDI, but its flange shows its a motor from Mabchi...
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here is the fan to give the load to motor...from an A/C blower...
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here is the same circuit and same preset...only difference is the wires...
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as i do not have any good wires at home i turned to this burnt SMPS from a CPU...here it shows its capacity..but we know its only a theory..still it can hold more than 7 amps continuous...
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we never forget to add supressing capacitors with our motor, especially like this one can generate ample of back EMF, with SAW and Radio disturbances...
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and the set up is here..and its working...sure see an INSTRUCTIONAL VIDEO HERE....http://www.youtube.com/watch?v=9-HSQ1Ubeek
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sorry..here...
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by this video you can see how nice its...and its fully based on basic circuit...still you can go for even more nice one with MOSFETs...i will post it later...here you can see a mere TIP 3055 is driving the whole load here...if we add two or three at same pattern, means bridge together, it can pull up to 30 Amps..cool...here you can see i retained the same heatsink as before...nothing is happened...
OK...now i have one more thing to tell you all...here i am posting even more exciting thing about my next set up...you all told me , that if we want to get a high power, we need a good big powerful motor...!!! think again... here i show you a motor i got it from a junkyard, from the centre locking actuator of a car...actually it was based on 12 volts 3 amps.i reworked it for 5 volts 700 ma at load...
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and here you can see a mechanism, like before but witha great difference...its actuated by a TOY R/C...here you can see a toy gearbox is fixed in such a way to turn the potentio meter in to either directions...via two pulleys and a rubber belt.
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you can see the rec: here..based on 27.145 MHz. never feel inferior...it will gives us a range about 600 meters with a 5 meter antenna..(a piece of wire)...and here is the close ups for the sets up...the driven pulley is from a walkman idler while the driving pulley is a motor pulley from a taperecorder...a belt is used here , to drive..why..? yes we know a toy R/C can oly turn a motor in to two directions..so if we use a actuator arm, it will destroy our set ups...so here the belt will slips simply after the working perimeter...as a clutch..still powerful to hold the torque induced by the variable resistor...
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and i used a toy gear box here to reduce the motor speed and to generate a good torque...you can see here how nice and simple it is....!!!
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and the final set up here...you can see the instructional VIDEO HERE.....http://www.youtube.com/watch?v=sPelbpz7wBM never forget to see it..you can see my motor set up is just working as to the big powerful motor as RS550 rated at 5.5 Amps..!!!! and still it weighs more than 75 grams...but here you can see my motor is weighing only 25 grams after rework...but still it delivers the equal power as RS 550...and the current drainage is...merely..below 700 Mamps..!!!! feel inferior..? NOOO i will post a video of my Hover craft, later, made out of expanded polystrene and with this motor...it works ever nicely...ommmmmppssssssss...so i request you all , because i know, there are many , with a great knowhow, to do goodies like these....i hope with this article i could inspire some friends...like all you inspired me...we never sit with layness...think about Write Brothers...and Dr Abdul kalam Azad...President Trueman..and Churchil...all they taught us to DREAM BIG..THINK BIG..AND TRY FOR IT..AND REALIZE IT....so friends..never forget to post all of your goodies here...
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i have one more humble request...i posted here this set up, not to boast about me...or to show nothing...but to inspire all of my friends, as you all inspired me...i was in a lazy mood until i join this prestigious forum...i tried many at my home land..and all of them rejected my registration form...so i was even more desperate...so i got accidently this address from my elder brother Mr Krishna, and tried..then after joining, i saw amazing models and stuffs here...WWWOOOWWWW...all it are far beyond imagination...and lots of informative stuffs and lots of veterans...by then i shared many things from you all...many models..ideas..techs and tips...advices...suggestion..all once i thought impossible to overcome...now i am too happy...but still a request...i know some will make fun on me...because of my gender...here in my native people call me as "VATTU PENNU" means VATTU means MAD and PENNU means GIRL...some call me as "BHRANTHI" means again MAD WOMAN...some like "PENNAANU"..means half woman and half man...and at home my Maa call me as YAKSHI..means ghiest..when hearing this some time i feels funny but some time feel a deep pain..so i dont know why i born like this...
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Friends..i hope you also try some thing like this..and sure must share with us all...waiting for good ideas...now my hands are trembling with fear...heart is pumping a lots...sweating..its 1:50 noon here..my Maa never knows about my trip to here..i got enough at morning for avoiding sleep at last night to shoot videos for you...now my cheeks and ears are swelled..by pinch...from Maa...if she caught me for this she will slice me in to 7 pieces and will throw in 7 seas...ohh..i have a drive back of 1 hour again...so i hope this article will help you all..like you all helped me...suggestions and corrections are welcome, because we can make our efforts even better...so i am leaving now...its too late...good night...
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Cracking job Rathi, :-)) im gonna give this one a go some point in the near future
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Sure Road runner..thank you..must post your ideas here..i have to go now..its too late..my Mom is calling me...i think i am caught up by her...sorry will be back...Merry Christmas and Happy new year...you all....
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with talent like you have you should be running INDIA as president, never feel inferior .we grown men and women are called because we have big boys toys. but who cares we do as we please it is ower choice.
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Hi Rathi, please have a look at this:
http://www.modelboatmayhem.co.uk/forum/index.php?topic=27857.50;topicseen :} :-))
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Dear Rathikrishna,
Where I come from, a lady such as yourself, a lady who builds clever gadgets from discarded junk, and a lady who knows something about electronics, is regarded as a Goddess. You are indeed a huge inspiration to fellow members on this forum.
Just in case you are wondering, I am extremely handsome. I am also extremely rich.
I have also been known to exaggerate a bit.
What are you doing tonight? Do you fancy a date?
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Dear Rathikrishna,
Where I come from, a lady such as yourself, a lady who builds clever gadgets from discarded junk, and a lady who knows something about electronics, is regarded as a Goddess. You are indeed a huge inspiration to fellow members on this forum.
Just in case you are wondering, I am extremely handsome. I am also extremely rich.
I have also been known to exaggerate a bit.
What are you doing tonight? Do you fancy a date?
Now now PMk, behave yourself!!!!! What do you mean....You are very handsome.......I've seen the photos!! %% %% %%
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Ssshhh!... don't let Rathi know that.
Besides, the guitar in the photo is not really a guitar - it's a sitar in disguise. Perhaps I could gain her affection with a rendition of Indian-type serenades.
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Ssshhh!... don't let Rathi know that.
Besides, the guitar in the photo is not really a guitar - it's a sitar in disguise. Perhaps I could gain her affection with a rendition of Indian-type serenades.
Back are you :} :} %% leave my Favourite modeler alone
Peter {-)
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Hi..hi...thank you all...and wish all Merry Chrismas and Happy new year...
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Reading these posts I can only marvel at the talent of this young lady! Thankyou so much, I have thought of useing a volume control and a servo as a simple ESC but your ideas are brilliant!Never occurred to me to gut an electric drill for the motor and speed controller! It also makes me realise how lucky we are to beable to buy our bits and bobs, ready and and simple to use. Have a wonderful New Year, and only marry a Model Boat Builder!
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Nice...inspiring a lots...sure...
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So YOU are the legendary Rathikrishna ! :-) I heard about You after I posted a question and thought they were just jerking my chain ... Much like mythical stories about Atlantis, The Lost Cities of Gold and Mermaids ... {:-{
NEEDLESS to say, I'm ECSTATIC to see You are real!!! :} and am VERY impressed by what YOU can do!! :} (Sort of like MacGyver, only, the stuff you do is real!) :-))
THANK GOD YOU'RE ON OUR SIDE!!! ok2 :-) :-))
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"NEEDLESS to say, I'm ECSTATIC to see You are real!!!...." Hai RRS01.. sure i am real..why you all asking like this..? because of gender..? leave the gender issues behind us..i hope one day i will meet you all somewhere in a event of MBMH... but i am not a good modeller when compared to my just elder brother Mr Krishna, as you all may have seen many postings from him.sadly, now he is in bed due to a spinal injury, happened from a road accident...i hope he will be back with me soon...to help me...i have a kind request to you all..that is nothing, but please dont curse me because of my gender .. even at home i am too restricted beacuse..i am a girl...its a sad thing...so happy now..no way for sad thinkings...have a nice day...god may help us all...Rachu
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i think ther may have been a misunderstanding ime sure nobody would ever dream of criticising anybody on hear because of there gender sometimes some things get confused in translation :-))
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you may be a young lady but you have sure brightend up mayhem
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Well, I for one, don't hold your being a girl against you! :-) ( If anything, it's a PLUS!!!) ;)
What I'm ecstatic about is to see someone that can turn "junk" into something I find useful AND shows the steps to do it!! (what can I say, I am a product of the publik edjukasyun sistum of America <:( <:( and I need all the help I can get! %% %%)
;D :-))
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Good morning Friends...after joining in MBMH, i told you all i forget all sad aspects of my life..now i do not have any time o think sad things, as i am oo busy with my official responsibiliies along with modelmaking...thanks for the inspiration from you all....i told you still many of the postings are unexplored by me...i will take a int connection at home soon..so i know its a treasure is waiting for me as postings...in MBMH...its even more inspiring...yuuuuuummmmyyyyy........have a nice day..god may bless us..
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Just tried something, and it works! Take a Black and Decker Cordless Drill, one with Knackered Battery but with reverse and speed control. Take to pieces and seperate the various bits. Cobble up two servos to operate said Speed button and reverse switch. Fiddle around until the control throws are correct, Add 6 cell power pack, and EUREKA!!!! Motor with speed control and reverse, and robust to! If you wish you can use the gear box as well.Oh thankyou young lady for putting the idea in my head.( It was empty so there is plenty of room inside!)