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--- robotic:turbo [2020/03/05 23:59] – tony
+++ robotic:turbo [2026/09/26 22:01] (current) – [Conclusion] tony
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-{{:pilone.png |Cone icon by Fornax, CC-BY-SA 3.0, wikimedia commons}} ((PAGE UNDER CONSTRUCTION))
 <html><p style="text-align:right;">Published 18 Feb 2020</p></html>
 <html><p style="text-align:center;"><b><font size="6">Turbo Explorer</font></b></p></html>
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 ===== Overview =====
-I needed a platform to try out the Dagu //[[:robotic:explorer|Explorer]]// robot control board.  So I built one using a plastic plate from an old CD Rom drive, a couple of geared motors, wheels from a "Turbo Diesel" dump truck toy (a knock-off of the //Tonka// Dump Truck?), and an //Arduino Uno//.  I always try to avoid buying any parts, so recycle whatever is available.
+I needed a platform to try out the Dagu //[[:robotic:explorer|Explorer]]// robot control board.  So I built one using a plastic plate from an old CD ROM drive, a couple of geared motors, wheels from a "Turbo Diesel" dump truck toy (a knock-off of the //Tonka// Dump Truck?), and an //Arduino Uno//.  I always try to avoid buying any parts, so recycle whatever is available.
 ===== Hardware description =====
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 {{:robotic:explorer:dsc_0200a.jpg?300|Base plate cut to size}} {{robotic:explorer:dsc_0201a.jpg?300|Base plate with mounting bolts}}
-Originally I was going to use a broken toy dump truck as the platform, but the //Explorer// board did not really fit (and the corner sensors would not have been any use).  So I ended up just using two of its wheels.
+Originally I was going to use a broken toy dump truck as the platform, but the //Explorer// board did not really fit (and the corner sensors would not have been of any use).  So I ended up just using two of its wheels.
 {{robotic:explorer:dsc_0180a.jpg?200|Dump truck overview}}
-{{:robotic:explorer:dsc_0181a.jpg?200|Dump truck side }} {{robotic:explorer:dsc_0183a.jpg?200|Dump truck topside}}
+| |{{robotic:explorer:dsc_0183a.jpg?200|Dump truck topside}}| |
+|{{robotic:explorer:dsc_0186a.jpg?200|Dump truck front}}|{{:robotic:explorer:dsc_0181a.jpg?200|Dump truck side }}|{{robotic:explorer:dsc_0185a.jpg?200|Dump truck back}}|
-{{robotic:explorer:dsc_0184a.jpg?200|Dump truck underside}} {{robotic:explorer:dsc_0185a.jpg?200|Dump truck back}} {{robotic:explorer:dsc_0186a.jpg?200|Dump truck front}}
+| |{{robotic:explorer:dsc_0184a.jpg?200|Dump truck underside}}| |
 {{robotic:explorer:dsc_0188a.jpg?200|Disassembled dump truck}}
-The two, 50 year old, 6V geared motors ([[:electronic:actuator:dcmotor:richard|Marx "mini Richard"]]) were bolted to the plate and a single old furniture castor wheel was mounted using old Meccano L brackets on the front.  As they are mounted 180° relative to each other, one motor has to run in reverse, this will probably accentuate any differences between them, the software will have to compensate for their different rotational speeds.  The geared motors were bought to use in building a toy long before micro processors or micro controllers were ever invented, but never used.  They have an adjustable gearbox that allows selecting gear ratios from 3:1 to 60:1.    The wheels were mounted on the axles with their outsides facing in.   As the hubs were recessed this allows the gearbox on the end of the motor to fit inside.  This results in the wheels being mounted on the axles closer to the platform (the gearboxes extend beyond the edge of the platform).
+The two, 50 year old, 6V geared motors ([[:electronic:actuator:geared:richard|Marx "mini Richard"]]) were bolted to the plate and a single old furniture castor wheel was mounted using old Meccano L brackets on the front.  As they are mounted 180° relative to each other, one motor has to run in reverse, this will probably accentuate any differences between them, the software will have to compensate for their different rotational speeds.  The geared motors were bought to use in building a toy long before microprocessors or microcontrollers were ever invented, but never used.  They have an adjustable gearbox that allows selecting gear ratios from 3:1 to 60:1.    The wheels were mounted on the axles with their outsides facing in.   As the hubs were recessed this allows the gearbox on the end of the motor to fit inside.  This results in the wheels being mounted on the axles closer to the platform (the gearboxes extend beyond the edge of the platform).
 {{electronic:actuator:dcmotor:dsc_0237a.jpg?300|Motor and wheel assembly}}
+{{robotic:explorer:dsc_4967a.jpg?200|Castor wheel}}{{robotic:explorer:dsc_4969a.jpg?200|Castor wheel}}{{robotic:explorer:dsc_4973a.jpg?200|Castor wheel}}
 {{robotic:explorer:dsc_0202a.jpg?300|Mounting standoffs, motors, and wheels - underside}} {{robotic:explorer:dsc_0203a.jpg?300|Mounting standoffs, motors, and wheels - topside}}
-The castor wheel has a ball-bearing axle, so rotates freely and is capable of operating with a far greater load that this robot will ever impose on it.  The positioning of the components was dictated by the hardware - the motors were mounted facing opposite directions, not quite touching, which left their gearboxes and axles protruding beyond the edge of the platform.  The wheels needed to be far enough forward to that they did not impede the corner sensors.  The front castor wheel was mounted in the centre, as far forward as possible.  Meccano L brackets that resulted in the platform being level were chosen to mount the castor wheel.  The positioning of the standoffs to mount the Explorer board was dictated by the mounting holes of that board (a template was used).  Washers were used so as to not stress the plastic parts too much, fibre washers were used in a couple of places as it is easy to trim a tangential flat along an edge of them to get them to fit against pre-molded protrusions on the platform (could have just filed down the edge of a metal washer instead).
+The castor wheel has a ball-bearing axle, so rotates freely and is capable of operating with a far greater load than this robot will ever impose on it.  The positioning of the components was dictated by the hardware - the motors were mounted facing opposite directions, not quite touching, which left their gearboxes and axles protruding beyond the edge of the platform.  The wheels needed to be far enough forward so that they did not impede the corner sensors.  The front castor wheel was mounted in the centre, as far forward as possible.  Meccano L brackets that resulted in the platform being level were chosen to mount the castor wheel.  The positioning of the standoffs to mount the Explorer board was dictated by the mounting holes of that board (a template was used).  Washers were used so as to not stress the plastic parts too much, fibre washers were used in a couple of places as it is easy to trim a tangential flat along an edge of them to get them to fit against pre-moulded protrusions on the platform (could have just filed down the edge of a metal washer instead).
 {{robotic:explorer:dsc_0204a.jpg?800|Assembled platform overview}}
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-=====Assembled robot======
+===== Assembled robot =====
 I then mounted the //Explorer// board together with an //Arduino Uno// and battery pack.
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 For the motors, the //Explorer// board uses 2 pin Molex connectors the same as found in many PC power supplies (internal plug connecting the mains wires, c0mes with high current wires attached).   I modified an 8 AA cell battery pack to accommodate just 6 AA cells to provide a 7.2 to 8.4V battery for the system, found a plug (ex PC speaker I think) that matched the //Explorer// power jack.   Strangely the //Explorer// board has large-pinned sockets for the outgoing power to the motors, but only a tiny battery socket through which all that power has to come!
-=====Software=====
+===== Software =====
 The Dagu example software was useful in understanding how to drive the edge sensors.
+===== Conclusions =====
+Experimentation with this robot platform was cut short by one of the motors stripping a gear, perhaps the motors were more worn out than I remember, or the plastic/nylon gears had simply dried out and become brittle with age.  Unfortunately I haven't got an alternative low geared motors to replace it with.
 ====== References and Additional Resources ======

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