To finalize the story of our hardware development, let me show you the budget, i.e. the money we spent on building the robot in the table below. There are two numbers for each expense. The “nominal price” denotes the approximate minimum amount of money one should expect to spend on a particular item. The “we paid” price denotes the actual amount we had to pay. It is nearly always different from the nominal price for two reasons:
- In some things, such as the smartphone and CNC manufacturing we got help from the sponsors (Nokia, Tööstusplast, Tartu University Institute of Technology and the Robotics club of the University of Tartu). Thus, we spent less than the nominal price.
- For other things, we spent more either because we bought back-up items (you never know when something is going to burn so this is always a good idea) or because we did not know exactly which particular option we would need and had to try different options.
I might have forgotten or left out something, but the table below should give a reasonable impression of a minimal expense sheet for a robot like Telliskivi. The prices are in euros.
|Item||Nominal price||We paid||Remarks|
|Electronics (275.00 | 325.73)|
|Miscellaneous (55.00 | 37.28)|
|Sockets, pinheaders, buttons, etc||15||18.18|
|LiPo 3-cell battery||30||0||Provided by the Robotics club|
|Battery voltage converter circuit||10||19.10|
|Main PCB & motors (140.00 | 217.70)|
|Main (motor control) PCB||35||0||Provided by the Robotics club|
|Motors||60||122.20||We ordered two pairs, just in case|
|Wheels, wheel mounting hubs, motor mounting brackets||15||49.70||In the end we did not use the wheels nor the motor brackets. We did need two sets of wheel tires and mounting hubs.|
|Coilgun (50.00 | 39.60)|
|Coilgun PCB||35||0||Provided by the Robotics club|
|Capacitor with mount||5||9.60||We bought two, just in case|
|Coilgun wire||10||30.00||We tried several options|
|Bluetooth module (30.00 | 31.15)|
|Mechanics (130.00 | 114.34)|
|Nuts and bolts, spacers, rubber bands, springs, ball bearings, grease, …||30||92.52|
|Sheet plastic and CNC cutting||50||14.07||Tööstusplast sponsored most of the manufacturing. The “nominal price” is an optimistic guess.|
|Sheet aluminium and laser cutting||50||7.75||Metec sponsored most of the manufacturing. The “nominal price” is an optimistic guess. The “we paid” price includes the price for restoring a lathe and a drill broken by us.|
|Other (0.00 | 105.51)|
|Postage and taxes on stuff ordered from Pololu and Proto-pic||0||105.51|
|+ Nokia N9||600||0||Provided by Nokia|
Let me summarize this to those of you not interested in detailed numbers.
- If you are willing to make a similar robot, be prepared to spend at least 400 euros. Out of those, you will spend about 100 on raw materials and manufacturing, 100 on microcontrollers and PCBs, 100 on “large” components (motors, capacitors, battery) and 100 on all kinds of nuts, bolts, connectors and wires. If you plan to order stuff from abroad, prepare another 100 for shipping and taxes.
- You might easily end up spending at least twice the nominal amount on some articles either for experimenting or for safeguarding against failures on the last moment. This can double your numbers up to 1000 euros.
If you now include expenses on junkfood, transport and the sleepless nights spent by the four team members making and programming the robot, you’ll see that participation in Robotex is, in fact, a very expensive project (for a student, at least). But it’s worth it none the less!