Krazatchu Design Systems

Arduino Compatible Line Following Robot

20 April, 2011 krazatchu

An Arduino compatible line following robot was designed and built in conjunction with the Ottawa Robotics Enthusiasts group: http://www.ottawarobotics.org/.

The robot uses QRE1111 reflective IR sensors for line detecting, an ATmega328 running the Arduino bootloader, an on board USB to serial converter based on the FTDI232RL, a TB6552 H-bridge driving gear motors and battery power is boosted by an LTC3401 boost regulator. The motor mount/batter holder was CNC machined from a single block of one inch nylon stock. The wheels were courtesy of a dollar store toy truck, four rubber wheels for one dollar.

In the video seen below, the robot is running some rudimentary Arduino code for testing purposes. More information, schematics, Eagle files as well as PIC based designs by Aaron of http://aaronramsey.com/ can be found on the Ottawa Robotic Enthusiasts Wiki at: http://wiki.ottawarobotics.org/index.php?title=Line_Follower

1) PCB 2) Schematic 3) Video below

Solder Hotplate

22 November, 2010 krazatchu

To perform low temperature soldering of laser diodes a hotplate is being designed and built. It consists of two parts, the heater and the controller.

The heat source is four 5 ohm 25 watt resisters attached to a half inch aluminum plate.
The base of the heater was milled from a solid block of maple. An NTC is glued into a hole in the back of the plate for temperature feedback.

The controller is sporting an AtMega8 running from it’s internal RC oscillator at 8MHz.
It features a PID loop for fast acquisition and control of temperature. An LCD as well as serial (RS232) connectivity are being used for debugging and visual feedback.

Currently it is being used as a thermal data logging test platform to investigate the behavior of heat transfer, thermodynamics…

1) Schematic 2) CAD model 3) Resistive heating 4) Hotplate surface
5) Sensor Calibration 6) Experimental data 7) Simulation data 8 ) PCB

Soldering Hotplate Version II

It was found that the initial version took an undesirably long time to reach a given temperature as the 50VA transformer limited the applied power. It was decided that the DC power scheme be revised to eliminate the bulky transformer and AC phase angle control be implemented instead.

A hairdryer consisting of 3 heating coils and an axial DC fan was salvaged for version two. A new heating plate was designed and CNC milled to accommodate one of the salvaged heating coils. An 8mm trough, 300 mm long, lined with fire cement for electrical insulation, now holds a 25 ohm coil. Utilizing phase angle control, this should equate to a maximum power of 575 watts.

The axial DC fan will be added to the design to assist in rapid cooling for faster solder setting times. As well, a new temperature sensing system will use two thermocouples, one internal and one external to provide more accurate feedback via a pair of MAX6675?s. The circuit layout is currently under review and parts are awaiting arrival.

Blog Electronics old content

Hexapod Leg with capacitive postional feedback

8 November, 2010 krazatchu

A leg system driven by screw coupled to a DC motor. The circuit board consists of rotary capacitive feedback mechanism, micro-controller and DC motor drive.

1) Side View 2) Capacitive feedback (active side) 3) Capacitive feedback (passive side)
4) Perspective view

Blog old content Robotics

3.5Hp Leaf Vacuum

30 October, 2010 krazatchu

Updates: The leaf vacuum was recently featured on woodgears.ca. You can find more pictures and details at http://woodgears.ca/misc/leaf_vacuum.html

A leaf vacuum was designed and built as a tribute to the endless pursuit of conserving one’s energy. Based on a material handling fan, the unit was designed as an attachment to a riding lawn mower. Utilizing a second hand Briggs and Stratton 3.5hp vertical push mower as a power source allowed for a low total project cost of under $40.

The impeller was designed in CAD with specific attention to the centrifugally induced stress on the assembly. The impeller base was CNC cut from 1/4″ 6061-T6 aluminum and the blades were CNC cut from 1/2″ nylon. The blower housing was constructed from plywood and aluminum fascia.

1) Impeller CAD model 2) Inside Housing 3) Impeller Blade 4) Video by Matthias Wandel

Blog CNC old content

Candle holder

30 October, 2010 krazatchu

This candle stick was turned by hand on a lathe more than ten years ago. The inspiration came from a glass candlestick of similar proportions at a department store.

Blog old content Wood

High Speed Router Mount

29 October, 2010 krazatchu

A router mount was designed and built to address the shortcomings of my milling machine’s low spindle speed (3600 rpm) for PCB machining. The mount bolts to the head of the mill and accepts a Proxxon router capable of 20,00 rpm with 1/8 inch bits. The mount was milled from hardwood and assembled with glue.

1) Bottom view 2) Side view 3) Perspective view

Blog CNC old content

SX3 CNC Milling Machine

29 October, 2010 krazatchu

My CNC milling machine is controlled via parallel cable from an old P4 laptop running Mach3. Spindle speed is 0-3600 rpm. The linear drive consists of C6 precision ball screws driven by steppers.

1) SX3 CNC mill 2) T-slot dimensions 3) Cutting 6063-T6 (below)

Blog CNC old content

LED Flashlight with 1w Constant Current Drive

30 August, 2010 krazatchu

A constant current LED driver was implemented to power a 1 Watt Cree P4 XR-E providing roughly 85 Lumens @ 350 mA. The constant current SMPS was based on the LTC3490 allowing operation from an input as low as 1 Volt. The entire assembly was retro-fitted into a late 1950’s Eveready flashlight housing.