MONGOOSE Assembly Instructions Introduction Mongoose was designed as an introduction to Mechatronics Page 1 of 12
Before you start The Mongoose is a complex kit and skipping instructions is not advised, the method below is the quickest and easiest method we could find. If you take your time the kit will provide you with a reliable, durable and fun robot chassis for your experiments. The main stages of assembly are mechanical, electrical and electronic. An x2 means you have to repeat this step twice for both the left and right halves. The Mongoose contains many small parts and it s advisable to keep any loose parts in a tray to prevent loss. MECHANICAL Chassis PreAssembly Modifing the gearbox frame The center frame piece must me modified before assembly. The front opening on both sides must be enlarged towards the center as shown in RED by approximately 5mm and is easily accomplished by carefully trimming the plastic with a small modeling knife or filing the material away. This makes room for the optical sensors. Apply foam spacers to the gearbox x2 Apply a self-adhesive foam spacer to both left and right gearbox halves. Apply optical interrupters to two encoder gears x2 Two of the BLUE gears require the addition of self-adhesive foil illustrated in RED to act as light blockers for the optical sensors. With a sharp x-acto knife carefully trim the excess foil along the shown with the GREEN line. The foil blocks IR light from the normally transparent to IR gears. Page 2 of 12
Assembling the axles x2 Short 28mm axle (round) Press fit the long yellow bushing as shown in the image. Hint: the small brass bushings are 4mm Long 50mm axle (hex) Thread a small silver grub screw into a brass hex hub. Slide the hub assembly over the hex axle and tighten (very tight) at 29mm from one end of the axle. Hint: An easier method than measuring is to preassemble the long axle. From right to left you need a brass spacer, silver collar, blue gear then yellow drive gear. When the brass bushing is flush with the end of the axle tighten the grub screw with the small Allen wrench included with the Mongoose kit. Installing the motor pinion gear x2 On a flat surface simply press a small purple pinion gear on to each motor as shown, do not press on the motor but instead apply gradual pressure to the motor shaft. Attach metal chassis sides to gearbox halves x2 Using a 10mm screw mount as shown, do not tighten yet. Using a single 10mm screw mount as shown, do not tighten yet. This short screw Page 3 of 12
ELECTRICAL The motor wiring harness x2 There are two sets of blue & yellow #22guage wire, they are approximately 13cm long with 12cm of insulation, 2mm of insulation is removed at the connector end and 8mm at the motor end. Each motor requires one large 0.1uf noise suppression capacitor, be careful not to mount the capacitor too close to the motor as it will be difficult to slide to motor into the gearbox later in assembly. A simple method is to line the top of the cap with the front of the motor housing. Now insert the 10mm bare end of the blue and yellow wires with the capacitor as shown below. Carefully solder the capacitor and wires to the motor terminals. With you wire cutters clip off the excess wire and capacitor leads. Make sure you put the blue and yellow wires on as shown; else your motors will run backwards. You can crimp the connector terminals to the 2mm bare end of the both wires. Hint if you are good at soldering; a very small dab of solder to the crimp terminal after crimping will improve the reliability of the harness. Page 4 of 12
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ELECTRONIC Necessary Tools (not included in kit) As with any electronic kit the following tools are essential: Low wattage fine tip soldering iron <50W Resin core solder Wire cutters or side cutters (small) Needle nose pliers (small) Slotted screwdriver (small) Phillips screwdriver (#1) Multimeter (Ohms, Volts) Assembly Final Assembly Initial Testing Page 6 of 12
Parts List Mongoose Controller Board Capacitors C1,C2,C3 0.1uf Small Monolithic Capacitor C4,C5 470uf Electrolytic 6.3V Resistors ¼W 5% Carbon (tan body, 4 color bands) R1,R5 220 Red, Red, Brown, Gold R2,R3 4.7K Yellow, Violet, Red, Gold R4 10K Brown, Black, Orange, Gold VR1 10K Variable Resistor (Horizontal) Semiconductors D1 1N5817 Schottky Diode D2 1N4148 Switching Diode IR1,IR2 LTE-302 IR Emitter Q1,Q2 LTE-301 IR Detector U1 PIC18F2525 Microcontroller U2 SN754410 Quad Half Bridge with internal diodes Connectors CON1 10 pin inline female connector CON2 20 pin R/A inline female connector CON3 2x5 R/A header CON4,6 4 pin Molex KK male connector CON3 2x5 R/A header 2x Spacers for Opto-Coupler pair Miscellaneous J1 Ferrite Bead 2x AA Battery Holder 1x 28pin Socket 1x 16pin Socket Motors Cx,Cx 0.1uf Large Green Motor Noise Suppressors Page 7 of 12
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Mongoose Gearbox Drive Train The Page 9 of 12
Mongoose Rotation Sensors The Mongoose is equipped with two independent wheel rotation sensors (one set per drive wheel). They are located on the gearbox and rotate 27x faster than the drive wheels. The pair of light and dark zones will transition 4x per gear rotation remember it s the transitions we re counting so a single rotation of a drive wheel will transition 108 times per rotation. The sensors are connected directly to PORTB,4 (right) and PORTB,5 (left) Page 10 of 12
Differential Drive Page 11 of 12
Mongoose and other projects are available at Retail Sales 255 College St. Toronto Ontario, Canada Tel (416) 977-9258 Fax (416) 977-4700 creatronpart@hotmail.com http://www.creatroninc.com Online Sales Dealer Sales & Technical Inquiries 4550 Dufferin St. Toronto Ontario, Canada Tel (416) 897-1962 sales@blueroomelectronics.com http://www.blueroomelectronics.com Info and all other inquiries info@blueroomelectronics.com Page 12 of 12