Stijn Coenen

Most commented posts

  1. Resistor Decade Box — 5 comments
  2. Dead Battery — 2 comments
  3. IN-14 Nixie Clock — 2 comments
  4. 555 Contest Entry — 2 comments
  5. ESR-Meter – Update — 2 comments

Author's posts

Safety transformer V1 – Update

I have made an enclosure from an old tool box:

scheidingstransfo
scheidingstransfo
scheidingstransfo
scheidingstransfo

CNC drill/mill machine V2 – Mechanical Part – Update

I’ve got some things for my cnc today.

2 Z-axis:
z-as
z-as
3 Steppers:
motoren
motoren
motoren
3-axis stepper controllers
sturing
Thanks Rik :D z-as

CNC drill/mill machine V2 – Electronics Part – Update

I’m going to drive the steppers with a chopper steering. I’m going to build my design around the L297 and L298 ic’s. The parts I’m going to recycle from the driverpcb’s I got from Rik (See the picture bellow). The reason I don’t use these pcb’s like this is because if I connect a stepper motor then it already starts to turn without a signal. And the input signals are not universal.

Stappenmotor sturing

CNC drill/mill machine V2 – Electronics Part – Update

I went shopping today icon_twisted.gif. I bought a pci card with a parallel port to drive my cnc.

PCI Par-poort

Etching Tank Heating – Update

The triac broke because my heating element pulls almost 5A and the triac is a 4A model. Therefore I replaced it with a BT139 triac.

Symmetric Power Supply 0-70V @ 5A

I want to build a new symmetrical power supply with the following demands:

-PC controlled via USB

-Current limited

-Symmetric

-The set value and the actual value of the voltage and current can be read on lcd displays.

My order of transformers at pollin:
pollin bestelling

The start of the build (I mounted the transformers on a piece of treaded rod and mounted it on a angle bracket)
pollin bestelling
pollin bestelling

UV-Exposure box V2

The previous version of my exposure box didn’t work good enough for my purposes, so I made a new one in the enclosure of an HP scanner. I also made a chronometer to help me time the exposure, the chronometer switches the lamps with a relays.

 

Pictures:.

Belichtingsbak V2

Belichtingsbak V2

Belichtingsbak V2

Belichtingsbak V2

Belichtingsbak V2

 

The circuit:

schema

 

The program (picbasic):

Device 16F627
Config   WDT_OFF, PWRTE_ON, LVP_OFF, MCLRE_ON, INTRC_OSC_NOCLKOUT
Declare         LCD_INTERFACE 4
Declare         LCD_LINES 2
Symbol Lampen = PORTA.2

Symbol Start =  PORTB.0
Dim hondert As Byte
Dim seconden As Byte
Dim minuten As Byte
hondert     = 0
seconden    = 0
minuten     = 0
Cls
DelayMS 500

Print At 1,1, "C Elek"

Print At 2,1, "Stynus"
DelayMS 1000
Print At 1,1, "      "
Print At 2,1, "      "
Print At 2,1, "0 :0 :00"

GoTo Begin
Begin:
Print At 1,1, "OFF"
If Start = 1 Then
    bla:
    DelayMS 50
    If Start = 1 Then
        GoTo bla
    End If
    If Start = 0 Then
        High Lampen
        GoTo Loop:
    End If
End If
GoTo Begin

Loop:

Print At 1,1, "ON "
Loop2:

If Start = 1 Then
         DelayMS 50
    bla2:
    If Start = 1 Then
        GoTo bla2
    End If
    If Start = 0 Then
        Low Lampen
            hondert     = 0
            seconden    = 0
            minuten     = 0         
        GoTo Begin
   End If
End If

'tijd op Lcd:
DelayMS 3.98
hondert = hondert + 1
If hondert = 100 Then
    hondert = 0
    seconden = seconden + 1
End If
If seconden = 60 Then
    seconden = 0
    minuten = minuten + 1
End If
Print At 2,1,"  :  :"
Print At 2,1,@minuten

Print At 2,4,@seconden
Print At 2,7,@hondert
GoTo Loop2   
End

 

The HEX-file: Download.

PIC Controlled Robotcar

This is a project I started 1 year ago but I never finished because I could not program pic microcontrollers. The goal was to build a car with 2 micro switches on the front. If these switches hit something the car should reverse and continue in another direction. As an extra difficulty I’ve put some leds on it (head lights, indicators, brake light) that have to be lighted on the correct time. I’m restarting this project because I’m learning picbasic now.

 

Some pictures from what I have already:

PIC bestuurde robotwagen

On this picture you can see the micro switch.:

PIC bestuurde robotwagen

The leds:

PIC bestuurde robotwagen
PIC bestuurde robotwagen

The motors:

PIC bestuurde robotwagen

PIC bestuurde robotwagen

Update: This project is stopped because the car is lost somewhere in my junk. I didn’t search for it because it didn’t work very good (The front axle is solid, so the car cannot turn good).

TDA2005 Amplifier

For this amplifier I used a amplifier board from a tv. The circuit drawings can be found here: Circuit right, Circuit Left, Pcb.

This amplifier needs a DC voltage of 33V. To create this voltage I used a transformer from an old printer, it delivers 21VAC (50VA). I’ve put a rectifier and some caps after the transformer. The case is recycled from an old vcr.

Some pictures:
Versterker
Versterker
Versterker

The transformer
Versterker

The rectifier + capacitors (7500µF in total):
Versterker

The speaker terminals:
Versterker

I wanted a volume control with buttons, so I made this circuit that generates analogue voltages with PWM.
schema

The pcb with the pic on it:

(On the left is a 5V power supply for the pic 30V ==> 15V ==> 5V)
Versterker
Versterker

This experimental pcb is not really reliable, so I made an etched pcb of it. When building it in I was a bit to enthusiast so I forgot to take pictures. However I do have the print-layout (which contains a fault at the pull-down resistors). Download pcb lay-out.

As you can see, I left 1 voltage regulator of the board. This is because I found a 15V regulator on the amplifier pcb.

The front panel:
frontplaat

(The panel looks crooked, but that’s just from pasting 2 images together)

Tube Amp

I had a lot of tubes lying around, so I decided to build a tube amplifier. The circuit diagram is drawn by Mat Jansen on “elektronicaforum” (Thanks Mat!). Link.

schema
A drawing of how the amplifier is going to be looking:
3D tekening