Scoot: The Kitten Bot
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Why did we make Scoot?
Inspired by many mini bots that the team and it's mentors have interacted with over the years, Scoot was developed for team 6762 as a minimal entry point to explore the feasibility of a swerve drive for a robotics in-season bot.
What is Scoot?
Scoot is a robot with a 3d printed chassis that uses 2 of Rev's swerve modules and a full FRC control system. This way, the team can experiment with many season-legal swerve libraries, or roll their own (we are definitely not ready for this). This also allows a team to purchase only two modules versus the 4 a typical swerve bot has.
Why only 2?
Swerve is expensive. Four Rev Swerve modules costs ~2282.50. That is a large investment for a design that may not be a good fit for a team. This solution allows a team to dip their toes in the waters of swerve relatively inexpensively.
How much will this cost?
We do not have a full BOM yet, but the general estimate is below.
The price of each swerve module, motors and controllers...
| Number | Item | Price | Desciption |
|---|---|---|---|
| 1 | Rev Swerve Module | 305.00 | this comes with the Rev Through Bore Encoder We purchased the plastic ones for testing, and the aluminum for competition. There is a known issue with the v1 plastic wheels. |
| 1 | Neo (no pinion) | 52.00 | |
| 1 | Neo 550 (no pinion) | 29.50 | |
| 2 | Spark Max | 92.00 | |
| Total | 570.50 |
Total General Cost
| Number | Item | approximate cost of the number listed |
|---|---|---|
| 1 | 1Full FRC Control System: Radio, PDP/PDH, POE for Radio, Rio 1 or 2, RSL, | ~950 |
| 1 | Optional: We substituted the Rev POE cable for the Rev Power Module. This is not tournament legal, but is working for us. | 11.99 |
| 1 | Optional: Small PDP. We used this one from Amazon | 19.99 |
| 1 | Optional: 12Ohm terminating resistor. If you substitute the PDP, you need a terminating resistor for the Can Bus. | .15 at Digikey, 5.00/3 at Amazon |
| 18 Gauge cable for the RSL | 11.99 | |
| 12 Guage cable for all motor and power connections | 12.98 | |
| 22 Guage cable for the rio and CAN | 10.48 | |
| cable connectors We used Anderson for the battery and Wago for all other power connectors molex/ dupont for CAN | 35.00 for 50; more than you need for this project | |
| 2 | swerve modules | 1141 |
| Ring or hook Connectors for our PDP | 14.99 | |
| ~801.81 g | 3d Fillament | 11.99 |
| Fasteners for control system (we used velcro) | 7-20 depending on the brand and length | |
| 4 | #10 bolts for the swerve modules and securing the base | 5.00 |
| 1 | 2 inch Swivel Caster; We used this one because we had it in our shop, but one without a brake would be even better | 7.50 |
| 1 | Limelight or other targeting camera, Optional | 200 - 400 |
| 1 | battery; We use one of the Studica batteries | 44.99 |
| Total | ~2303.05 |
That sounds like a lot, however, other than the swerve drives themselves, we were able to source all of the materials from team stock. So, for us, it cost us clocer to $650.00. Many of the materials are also reuseable. Another aspect of the design is that you could use scoot as the control board for a full-size bot with four swerve modules.
CADD
(https://cad.onshape.com/documents/dc911cfa8b3dccdac654b76b/w/eddf5a90f3b74427297dde25/e/3c74e6053ab6216a8b7a64ff)
Changes that have not made it into our CADD designs
- We are using the Amazon PDP and terminating resistor because it is smaller
- We put the PDP under the chassis to allow more flexibility on top
Some images of our current bot