It’s hard to find good resources of electronic components and sensors for your projects, especially if you are just starting hardware hacking. Well, this is at least the way I felt a few months back, so here is my list of best UK based electronics hardware stores online where you can find pretty much everything you need for you next Arduino project.
www.coolcomponents.co.uk – great resource for Arduino shields, sensors and wireless communication hardware.
www.robotbits.co.uk – wheels, chassis, gearboxes and various robotic kits ready for you to assemble based on Arduino.
oomlout.co.uk – great store for Arduino stuff, value starter bundles, essential tools, outstanding customer service and prompt delivery. With every component purchased you will get a very nice bonus – printed schematic for breadboard with instructions on how to connect the component to Arduino like this one.
www.rapidonline.com – if you are more a do-it-yourself guy, this is an ideal resource for you. Store features everything from microcontroler ICs, LEDs to discrete semiconductors, sensors, gearboxes and complete robotic kits. Very competitive prices and free shipping for orders over £40.
I’d be very happy to hear of any resources that you know in the comments. :)
Started thinking about the logic for the robot. The first one that I used in my prototype from LuckyLarry’s website seems to be too basic, so I did a quick brainstorm and came up with the flowchart above. The logic adds the complexity of using a range finder sensor on top of the servo. Robot should drive forward, unless it encounters an obstacle closer than 20cm. Then it should stop, look around and determine the next free path it should go. The most challenging bits are the ones that I colored in red: this requires some sort of sensory “knowledge” of the direction of the robot. If I had a spare accelerometer, everything should seem more simple: just get the data from the accelerometer and calculate the direction of the robot when it turns. All I have now is just SRF05 range finder so another thought came to my mind. At the point after robot scans the surrounding area, it should know the distance to the surrounding area with 10 degree resolution. For example:
- -90 deg | 70 cm
- -80 deg | 60 cm
- -70 deg | 50 cm
- -60 deg | 50 cm
- -50 deg | 40 cm
- -40 deg | 40 cm
- -30 deg | 30 cm
- -20 deg | 20 cm
- -10 deg | 20 cm
- 0 deg | 20 cm
- 10 deg | 20 cm
- 20 deg | 20 cm
- 30 deg | 20 cm
According to the logic, robot should choose path (1) by turning -90 degrees. Considering that before the turning head is facing 0 degrees, it should continue turning, until it determines that the distance is more than 70cm to the closes object, so the range finder should read all the way from 20cm to 70cm with a threshold of +-5cm.
Huh, seems that hardware setup was the easiest bit. Building smart software to run the robot is a bigger challenge and that’s what makes this project so interesting. :)