Tue, 31 Dec 2013
PF 2014
I wish a pleasant year 2014 to everyone who reads this blog.
Thu, 19 Dec 2013
Arduino SCX Digital to USB interface
I have a SCX Digital slot cars set, and some years ago I bought an interface box for connecting it to the PC using a RS-232 serial port. PC then can be used as a timer, lap counter, and race management. Now I wanted to make some modifications to the firmware (it uses AVR Tiny 2313 chip). I have discovered that the author does not sell this version anymore, it has been replaced by a newer version with USB. So I kindly asked the author whether he can provide me the source code for the firmware for the old version. I have got the following reply:
Hi Jan
Sorry, I do not share any of my software.
Well, whatever. It is of course his choice to keep the firmware of the abandoned version for himself. But in the meantime, I've got some experience with electronics and microcontrollers (see my other projects).
Introducing SCXreader, my own SCX-to-PC/USB interface, built with Arduino Nano. It is fully open, including the source code of the firmware. It costs about US$ 6.50, way less than the current SCX-to-USB SEB interface.
Sun, 15 Dec 2013
Slot Car Tyres
The tyres of our slot cars are not as good as they used to be, so I wanted to buy new ones. However, the local seller has been less than helpful, so I searched the Net. Apart from U.S. slot car supply sellers (tyres for US$ 7.50, shipping into the Czech republic for US$ 25+), I have found this page, so I have decided to create my own tyres. The original tyres look like this:
Firstly, I have created the box for a new mold, using heavier paper with smooth finish:
The tyres are fixed at the opposite sides using dual-side adhesive tape. This allowed me to make a single-part mold only, and provide the pouring and air escaping holes:
The mold is made from OOMOO 30 silicone, bought at www.silikonycz.cz. I have used parafine release agent to avoid the original tyres sticking to the mold, but I think it was not necessary after all.
The mold removed from the paper box:
Removing the original tyres from the mold. OOMOO is really stiff and soft, my previous experience with Lukopren 1522 silicone is worse - Lukopren would snap off when removing the models so deeply enclosed in the mold.
For the tyres I have used urethane rubber. I have tested two types with a different hardness. The red one is softer - Vytaflex 30, and the blue one is harder - Vytaflex 40. I have used So Strong pigments for making the rubber red and blue. All those materials were also acquired from www.silikonycz.cz.
And here is the final product:
It is much softer than the original tyres, and a bit looser on the rims (I have not used any glue so far, though). With the original tyres, the best lap time with F1 cars was slightly under 7 seconds. After the short testing ride with the Vytaflex tyres I clocked the best lap of 5.15 seconds, and average laps around 5.50 seconds. Impressive.