USB device for controller a shift register

This simple USB HID device is connected up to a shift register which is used to control a number of LED outputs. It proves the principle of using the shift-register as a serial-to-parallel interface. Data is sent from the PC via USB to the PIC microcontroller, which in turn clocks serial data into the shift register.

The shift register displays a series of 8 bits, as received on the serial line, on the output pins. We're simply showing the state of the output pins by connecting a surface mount LED

Scalexercise at BuildBrighton

Here's Other Chris and Mike at BuildBrighton Hackspace, testing the Scalexercise racing cars for the Dublin Mini MakerFaire.

 A few tweaks here and there may be needed for the final version, but as a proof-of-concept, it's looking really exciting. Pedal faster and the car zooms around the track.

Braking is proving a bit of a sore point, at the onboard mcu effectively has to wait for a timeout from the exercise machine before reducing speed which is why there's a delay between stopping pedalling and the car stopping.

 Perhaps it's time someone fitted a brake to an exercise machine?

 

Fuzz face distortion pedal effects

Video showing a home-made fuzzface distortion pedal effect. The PCB was deliberately made as small as possible so that the final circuit could be embedded inside the guitar, behind the scratchplate. At about 0:45 the video pauses while a second pedal is replaced. This second pedal uses the same circuit but different transistors and capacitor/resistor values to create a different tone. The first pedal is based on the older, original "fuzzy overdrive" circuit. The second uses components often seen in louder, fuzzier "distortion" effects.

Serial LCD with Flash eeprom

This is part of a larger project, for an electronic Blood Bowl board. Testing a number of ideas in one project - converting a parallel interface LCD into a serial interface, using a shift register and reading data from Flash-based eeprom to display on the LCD.

Sorry about the blurry image, but you should just be able to make out the string of characters as it cycles through a list of names, stored in the external Flash eeprom chip. The characters should read

• Blood Bowl
• Griff Overwald
• Varag Ghoulchew (ran out of characters!)
• The Mighty Zug

then cycle through them all again.

PIC controlled traffic lights

Here's a pretty cool set of microcontroller-powered miniature traffics lights from one of our youngest members. He's building an electronic toy set for his younger brother for Xmas and is using these to get starting with PIC programming.

Note how the sequence accurately follows a real set of lights - including that frustrating delay when both sets of lights stay red for a second or so - just in case any last-second idiots are trying to jump the amber light and squeeze through before the second stream of traffic is released!

Continuous rotation servo hack

In preparation for Robot Week Wales on 5th December, we're putting together some robot kits. And that means messing about with continuous rotation servos. Most of the off-the-shelf servos are pretty big and lumpy - we'd like to use the little micro servos, to keep the robot size small. So we hacked some micro servos from Oomlout

Stepper motor controller with jog function

This is a PIC18F4550 and a ULN2803A darlington relay controlling a stepper motor.
The PIC provides a USB interface to the host PC, allowing you to send a specific number of steps and a rotation direction. The motor can also be turned using the "forwards" and "backwards" jog buttons.

The noise in the video is not rowing neighbours, as suggested by some viewers, but a Radio4 play and my partner on a sewing machine in the other room!

In this example, I'm using a 1.8 degree stepper motor. I'm driving it using half-step rotation, so one rotation = (360/1.8)*2 = 400 steps. You can see this value being entered into the USB/HID app on the laptop - 400 as two bytes is 1(HB) and 145(LB)
Working this back, 1*255 + 145 = 400

When the "send data" button is pushed, the stepper completes one single, full rotation.