Arc Welding Effect for Model Railway Layouts Schematic Circuit Diagram
Now and again modelers looking to add something special and individual to their layout will want a miniature arc welding simulator. This project demonstrates that you need barely anything more than a microcontroller and the right software.
The circuit shown here uses a PIC10F200 microcontroller to illuminate LEDs D1 and D2 with differing frequencies and time lags. To ensure the effect produces the characteristic flashes of arc welding the two LEDs should be fixed as close together as possible. The insertion and removal of the welding electrode are represented by short breaks in the flickering. To cut off the welding light the circuit must either remove the supply voltage or else ground pin 8 (GP3). J1 provides an elegant approach to the latter solution. The welding effect is active with the jumper removed.
The software for the microcontroller can be downloaded free from the web at [1]. The configuration of the PIC is included in the ASM file but can also be carried out by setting all configuration bits to zero manually.
The PIC10F200 is a low-cost, high-performance, 8-bit, fullystatic, Flash-based CMOS microcontroller. It employs a RISC architecture with only 33 single-word/ single-cycle instructions. All instructions are single cycle (1 µs) except for program branches, which take two cycles. It delivers performance in an order of magnitude higher than competitors in the same price category. The easy-to-use and easy to remember instruction set reduces development time significantly.
High-Performance RISC CPU:
Special Microcontroller Features:
- 4 MHz Precision Internal Oscillator:
- in-Circuit Serial Programming™ (ICSP™)
- In-Circuit Debugging (ICD) Support
- Power-on Reset (POR)
- Device Reset Timer (DRT)
- Watchdog Timer (WDT) with Dedicated On-Chip RC Oscillator for Reliable Operation
- Programmable Code Protection
- Multiplexed MCLR Input Pin
- Internal Weak Pull-ups on I/O Pins
- Power-Saving Sleep mode
- Wake-up from Sleep on Pin Change
