I have been looking at the Rollplay Uprider for use indoors and was pleasantly surprised by the controller PCB in it. The PCB in the model I bought is marked W208J B-01g 2018-4-23. I investigated further to see if I can use the original PCB instead of having to replace it with another motor controller and processor, and so reduce the conversion cost.
The PCB is able to drive both motors independently in either direction with speed control, as well as having a battery voltage monitor and charging circuit. The PCB uses a Nuvoton N79E715AT28 microprocessor which is a 8051 based design with 16 KB of flash memory - plenty of room for lots of code.
The PCB connector J11 and processor include 2 analog connections (used for speed / direction control) and a switch used as a drive enable. It is easy to connect a joystick or direction buttons with minor changes to the wiring harness.
They kindly included a programming connector footprint on the PCB (marked J3). A little soldering work allows a 5 pin connector to be attached to the board, which connects to the ISP-ICP programmer available from the https://direct.nuvoton.com/en/isp-icp-programmer webpage for $20 + $6.99 shipping, but you will have to make up the programming cable.
There are some free C compilers (Keil up to 2KB of code, or SDCC) that can produce the required hex files for the programmer.
I ran my first program on the board this weekend using an Adafruit joystick and got very reasonable results. The speed was quite controllable and it was reasonably quiet. I want to make some more changes to the deceleration control.
So far I have found 2 issues:
- One of the motor controllers did not work in reverse on one of the motors. This appears to be a bad IC. I have a replacement part on order and will try it. The main issue is that the Uprider never uses the motors in reverse so this part of the PCB cannot be tested with the original Uprider software.
- The Uprider has two caster wheels, one in the front and one in the back, to prevent the uprider from tipping over forwards/backwards. The front caster is mounted vertically, but the back caster is mounted at a slight angle backwards. This seems to make it work well going forwards, but when moving in other directions the rear caster rotates and lifts the drive wheels slightly reducing their contact with the ground. There are a couple of washers where the casters are attached to the frame. Removing the washers seems to help but needs more testing.
Two questions for others who have used an Uprider chassis:
- Did you have a solution for the back caster wheel to allow it to turn and go backwards ?
- What seats have people used and how easily are they to attach to the uprider base ?