Showing posts with label DIY. Show all posts
Showing posts with label DIY. Show all posts
Tuesday, October 20, 2015
Homemade Hobby CNC router part II
Updated now working with full threaded rod that will move the axis. Connecting the rod to the stepper motor, i used those rubber guide of old inkjet printers as shown.
The stepper is a low torque from old fax machines i salvaged from my junks, almost all parts that make this a complete, A not perfect machine.
the dremel tool was changed due to the old one not rotating fast and sometimes halt when trying to cut through the material, the latter perfect fit for engraving.
Video of the first run, and using KCAM 4 software instead of MACH3 for i cannot configure the latter to move the steppers correctly.
here, i am engraving my daughters name in a 2mm thick acrylic sheet, due the movement of the Y-axis and the tolerance of the shaft to its cradle, sometimes the position of the cut is out of position.
Needing to tweak the number of steps the motor must turn, finally i am up to engrave a full logo on a an acrylic sheet.
some of those first tries engrave.
the finished HOMEMADE Hobby CNC router out from salvaged parts out of my junk back home.
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Video of the first run, and using KCAM 4 software instead of MACH3 for i cannot configure the latter to move the steppers correctly.
here, i am engraving my daughters name in a 2mm thick acrylic sheet, due the movement of the Y-axis and the tolerance of the shaft to its cradle, sometimes the position of the cut is out of position.
Needing to tweak the number of steps the motor must turn, finally i am up to engrave a full logo on a an acrylic sheet.
some of those first tries engrave.
Battery Voltage Indicator
Many enthusiast and motorcycle rider ride their bike, using electric starter to start the engine undoubtly knowing the battery gone flat, charging system might have gone down but no visual indicator that the system indeed is not charging or have problems...so in the first place why not build one to visualize you anything bout battery voltage on board the bike.
Using pic microcontroller and little components, you can create one like as shown.
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Using pic microcontroller and little components, you can create one like as shown.
Motorcycle Voltage Regulator DIY
Introduction:
This project is a voltage regulator for a 3-phase, permanent-magnet alternator found on motorcycles. The same design can be used for single-phase alternators simply by eliminating some parts. This project only describes the regulator, even though a rectifier is typically integrated into the unit.
Circuit Analysis:
Please refer to the circuit diagram during the analysis of the circuit.
Overview:
The way this type of regulator controls the alternator’s output voltage is by simply shorting out the stator winding for one cycle of the ac waveform. This is called shunting. This is done because it is much easier to short-circuit an inductor (the stator winding is an inductor) than to open-circuit an inductor. Very high voltages are induced when an inductor circuit is opened. This may cause a breakdown in the winding’s insulator.
The device used to shunt one cycle of one phase is an SCR. A silicon-controlled rectifier acts as a diode when triggered at its gate. It stops conducting when the current drops below a very low threshold value. Once it stops conducting, it will not conduct again until it receives another gate signal.
A voltage detection circuit is used to trigger the gate on each of the three SCRs. The threshold voltage to trigger the gate is selected as 14.6volt (on the motorcycle’s system-voltage). This is when the gate would trigger if there were no capacitor as described in the next paragraph.
Since the voltage from an alternator fluctuates, the detection circuit will trigger during a peak in the waveform of one of the phases, but this causes the average voltage to be too low. To raise the average system-voltage without increasing the detection threshold, a simple capacitor is used to delay the triggering of the SCR gates. The capacitor acts as a filter to reduce the ac ripple going to the detection circuit. If the system voltage was strictly DC voltage (with no ripple) the gate would trigger at 14.6v and the average voltage would be 14.6v. In reality, the average voltage is always less than the threshold voltage and only approaches it as the ripple reduces. The actual trigger voltage is higher than 14.6v, but the average voltage is lower than 14.6v. As the ripple reduces, the average and trigger voltages approach 14.6v.
Another Motorcycle Voltage Regulator
The above picture in comparison with the other voltage regulator posted here SCR regulator was, this one uses differential amplifier to detect battery voltage and control SCR .This has a number of advantages over using a zener diode to directly trip the gate of the
SCR.
These are:
1)If the battery voltage is forced above 13.5V, the circuit limits the current into the gate of the SCR
preventing damage to the regulator when changing the battery
2)The circuit is more stable over temperature.
The main drawback is that the circuit is leaky. The differential pair should be connected after the ignition
switch to prevent the battery from draining when the engine is not used for a long period of time. This
connection is shown as MONITOR in the schematic. The output of the bridge rectifier ties to the battery at
the BATTERY connection.
With the differential pair, the base input for Q2 is connected to a voltage reference consisting of D1 and
R9. The base input for Q1 is connected to a voltage divider that monitors the battery voltage. When the
voltage on the base of Q2 is higher than the voltage on the base of Q1, Q1 will turn on shunting all of the
current from R5 to ground. When the voltage on the base of Q2 is lower than the voltage on the base of
Q1, then Q2 will turn on. This will shunt the current of R5 through the limiting resistors to the gates of the
SCR. The SCR will turn on and short out the phase. Since the stator voltages are AC, the SCR will reset at
the end of the cycle when the voltage reaches 0.
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