Ballistic Chronograph MK2 #DIY

DIY 3D Printed Ballistic Chronograph

A 3D Printed Ballistic Chronograph for $70 – $100 USD!

This ballistic chronograph is based on my original design, the MK1 (which can be viewed at https://td0g.ca/2016/07/28/ballistic-chronograph/). I’ve used the MK1 to take many high-speed photos, including a shot of a mach-2 bullet hitting a nice wine glass!  The new MK2 has the same performance as the original, but is much easier to construct.  It can be used for measuring high-powered rifles, paintball guns, and everything between!

3D Printed Ballistic Chronograph

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Edgerton, A High-Speed LED Flash #DIY

2019-07-25 – The list price of the well-designed Vela One has recently dropped.  I originally quoted it at about $1,750 CAD but unfortunately don’t have any proof.  As of today, the Vela website indicates it is exactly $1,526.70 CAD. The archive.org website shows that the price has indeed fluctuated over time.

2019-08-01 – A big THANK YOU to NQTRONIX who has kindly gifted me an active light probe of his own design.  The probe will be used with an oscilloscope to measure the flash duration, trigger response time, light output -v- current, and other helpful things.  I will update this post with the data once testing commences.  NQTRONIX put a TON of time into designing, testing, and optomizing his probe.  Please consider checking out his instructable page and leaving him a like or comment!

2020-03-20 – Main control boards are available at https://www.tindie.com/products/19592/.


EDGERTON

Named in honour of the legendary Papa Flash.

Some time ago I designed and built a ballistic chronograph and used it to take some high-speed photos of bullets striking glass. The results were great, but the photos were somewhat limited by the standard ‘speedlight’ flashes that I used – there was always some motion blur. Edgerton is a ‘High-Speed Flash’ which uses LED’s to make one-microsecond flashes to freeze motion.

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Simple Tally Light for OBS Studio

A FULLY Plug-and-Play Tally Light

My church (like many others) recently began streaming sunday services.  The staff had quite a job on their hands adjusting from a live audience with a small online presence to an online-only presence.  Subtle communication between the ‘techies’ and ‘actors’ was difficult, but a simple tally light made it simple to send a queue to the staff on camera automatically.  A tally light is simply a light that turns on when the camera is recording.

This tally light is a simple Raspberry Pi-based system which connects with OBS Studio over the network and illuminates a lamp when the camera is live.  The system does not need any external input – it will find OBS studio and save its address for future sessions.  If OBS studio moves to another PC, it will still find it.  The camera illumination is configured in OBS studio, so no need to change anything on the tally light.  Finally, if OBS Studio gets disconnected for whatever reason, the tally light will turn off and the Pi will immediately begin searching for OBS Studio again.

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High-Voltage FLASH Programming on ATTINY85

ATTINY85 High-Voltage Programmer

The Bubblegum Chip, Now With Steroids!

The Atmel ATTINY85 is a great chip (cheap, easy to use, supported in the Arduino IDE).  Unfortunately it only has 5 IO pins, which limits its usability.  There are guides on using a High-Voltage Programmer (HVP) to change the Reset pin into an IO pin.  However, that prevents you from programming the Flash (Program Memory) until you re-enable the Reset pin.

Thankfully the Flash can be programmed with an HVP, but the commands and protocol are different.  My USBtinyISP simply cannot be modified to be an HVP.  Using an Arduino as ISP (In-Service Programmer) on an ATTINY85 is fairly simple but doesn’t work if the Reset pin is disabled.

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Simple Sonic Anemometer #DIY

DIY Sonic Anomemoter

Measuring Air Flow – Made Easy

A sonic anemometer is a device that measures air velocity using sound. A speaker on one end of the device emits a ‘ping’, and a sensor waits for the ping to arrive. If the air is not moving, then the delay between ‘pinging’ and ‘receiving’ is always the same (kinda).

If the air is moving from the sensor toward the emitter, then the delay gets longer since the ping is traveling upstream. Conversely, if the air is moving from the emitter toward the sensor, then the delay gets shorter since the ping is traveling downstream.

I built this anemometer to measure airflow rates of various small fans.

Ingredients

All you need is an Arduino, an HC-SR04 ultrasonic distance sensor, a piece of 3/4″ PVC conduit, and a 3D printer. The 3D print file and firmware is available on Github.

3D Printed Sonic Anemometer

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PCB Jig + Lab Power Supply #DIY

I recently added a couple home-build devices to my home lab. The first is a well-designed PCB jig engineered by an electronics forensic expert. The second is a very cheap lab power supply using a Chinese step-down converter and an old battery charger.

The Jig

It seems I never have enough hands, especially while testing and troubleshooting a fresh PCB. As frustration was mounting recently, Thingiverse member Giufini seemingly heard my prayers – and shared his design for a PCB probe jig!

Thingiverse photo

At first glance, it looks somewhat hap-hazard. I built one, and must say that it is very well designed! The layout of the board is perfect for the PCB’s I work with. The towers and arms are easy to adjust and have a well-tuned flexibility to them. Finally, the acupuncture needles were simply genius! This design was even reviewed (and quite well received) on Superhouse.

PCB Probing Jig DIY

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500W Spindle Controller – Fixed!

You Get What You Pay For

While building my CNC mill, I bought a 500W spindle with a motor controller off eBay for less than $80 CAD.  The spindle and power supply needed some TLC right out of the box, but seemed to work fine.

Image From eBay of 500W Spindle & Controller

Then the incident happened… I was adjusting the ‘MAX’ potentiometer when suddenly the motor speed dropped to 5,000 RPM and wouldn’t increase!  I may have accidentally shorted the potentiometer with my screwdriver, but that shouldn’t have caused a problem.  This potentiometer is basically shorted to 0 ohms at one end anyways.

No adjustments to any of the potentiometers would change the motor speed more than a few hundred RPM.  I considered buying a replacement controller, but for $50 CAD I decided to have a crack at repairing this unit.  I ended up writing an almost-complete schematic of the controller and determining what one of the three IC’s are.

Schematic for 500W Spindle Controller / Power Supply

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High-Speed LED Pulsing Experiments

This page is currently being populated with past experiment data.  All future experiments will be added shortly after their completion.

The plans for Edgerton are available for anyone to build their own high-speed flash.  I designed the flash by building a prototype and doing lots of testing.  Until now, I haven’t kept an updated log of all the experiments performed on the LED’s.  Maybe some people would like to see all the details behind the designing and prototyping of the flash.  Others may be interested in designing their own high-speed LED flash.

The complete experiment logs can be found at github.com.

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Cheap Spindles & Power Fluctuations

While building my CNC mini-mill, I purchased a 500W air-cooled spindle from eBay.  It came with a power supply, which looked great and I (falsely) assumed it would work perfectly on my home-built mill.

Boy was I wrong!  The mill worked great as long as the spindle was turned off.  Whenever the spindle was on, there was a chance that the mill’s microcontroller would reset (bad), lock up (worse), or would suddenly enter an infinite loop (really really bad!) and an axis motor would begin moving in some direction until I noticed and stopped it.

After much work identifying and rectifying the causes, the power supply has finally been tamed.  Here’s a guide for anyone having the same issues.

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Cheap Trigger for High-Speed Photography

A simple trigger for high-speed photography is the ‘tripwire’ trigger.  Unfortunately few (if any) commercially available flashes are configured for this trigger.  Thankfully, an Arduino-based trigger controller is very easy to make.  I will also shamelessly plug Edgerton, an open-source LED flash specifically designed for high-speed photography, that can be tripwire-triggered without any major hardware!

How It Works:

A small bracket must be built for the muzzle of your rifle (or whatever you are using).  Two pins protrude from the end of the bracket and a fine wire is wrapped between the pins.  The pins are connected to a port (I use a 3.5mm audio port) which can be connected to Edgerton or the trigger controller by an extension cable.

When the projectile exits the muzzle, it passes through the wire and breaks it.  The two pins, which were once connected by the wire, are now ‘open’.  Edgerton or the flash controller detects that the pins are separated and a timer is started.  After the timer finishes, the flash is triggered.

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