Standard SAMrI Build Up

The JCM SAMrI minisumo Robot is straightforward to build, although we reccomend a minimum age of 12 for construction.

Below is a picture of our own completed SAMrI Robot, Tito. Notice he is waring aftermarket wheels. The axels and hubs will need modifing if he is to enter competition. Currently Tito is 115mm wide, so 15mm over the 100mm x 100mm minisumo regulations.

Please read the following alongside the contruction manual, this text is not intended to be comprehensive.

The total elapsed time for construction was 3 days, but total effort was in the region of 4 -5 hours, if you intend to complete the build in one session I suggest you read and re-read the construction manual and gather all tools and materials required for construction. This will save you a lot of time.

The picture below shows the SAMrI PCB part built, the order of construction was: Resistors, Capacitors, QRD1114 Sensors, Switches, LED

Note: If you intend to upgrade your SAMrI with the 3 additional short range proximity sensors, now is the time.. As you will see from the picture below the motors need to be removed to fit the center sensor should you wish to do this after construction is complete.

This picture shows the SAMrI completed Sensor PCB.

This picture shows the SAMrI completed Main PCB. Following the LED i added the IC Sockets, Motor Driver then D25 socket and battery connections. I added the brass connections between the main and sensor PCB last.

Take great care when soldering the Motor Driver IC, take the time to ensure it sits straight.. as you will see mine does not, I didn't really consider this when soldering the underside of the board. My next SAMrI will have a straight motor driver IC. Please note this is an asthetic issue only, the SAMrI functions perfectly.

Once the PCB is complete, you can move on to gearbox construction.. follow the instructions in the manual, greese the gearbox well outherwise they can be VERY noisy.

After the gearbox comes the chassis. fold the chassis as directed, my chassis plate was too short, to make the traditional SAMrI shape, however if you bend from the front as directed until you have the back piece sicking up vertically then bend over 90 degrees 25mm up you will form chasiss as pictured below.. I will upload a tempate for this design soon. Personally I prefer the look :

I also recommend that you take the extra time to drill both the gearbox mounting holes and the inspection / adjustment holes. Do this prior to bending the sheet. You may find it helpful to glue our template to the chassis plate prior to drilling or bending, I attached the battery box with a couple of cable ties, I intend to move to a perminently fixed rechargable battery pack and will add recharge circutry to the prototype area of the PCB.

If you are bolting the gearbox to the chassis insert the bolts so the head is to the underside of your SAMrI to prevent then catching on the ground, don't forget the washers.

Finished... now for some testing, incidentally Tito currently tips the scales at 346grams.

I am using a minisumo Dohyo pdf from minisumo.org, with the standard program an A3 Dohyo is too small for testing.. when the SAMri hits the outer edge, it backs up so fast that by time it goes straight again its out of the arena. I reduced the speed to 50% and reduced the times to allow testing with the small Dohyo. You may also need to adjust the sensitivity of the edge detectors, especialy if the Dohyo is poorly printed.

Another picture of Tito in the Dohyo, if your SAMrI is behaving oddly check the sensors for operation by holding your SAMrI in off the ground and moving an object to each sensor in turn to see if you SAMrI responds. If either sensor seems in operative check the guide in the build manual, and the soldering of all components used by that sensor.

Assuming both sensors are operative but your SAMrI is leaving the arena, check the ride height and adjust sensitivity of the sensors until all is well. It helps here to program your SAMrI to only turn a little when the edge is hit, in this way you can may min follow the edge and drive just around the inside of the Dohyo. Do this in both directions until you are happy the edge sensing is working properly.

Some pictures of Tito waring his new (currently illegal for competition) wheels..