A look at Rejent Tool in 2013

Well things are proceeding apace in the shop these days. Over the last two years we’ve been pushing ahead and growing the shop in terms of equipment and technology.

I have a couple of photo’s, taken from the same spot over a difference of a little over 2 years.

A look at rejent too in November 2010
A look at rejent too in November 2010. a little empty looking.
A look at Rejent in February 2013
A look at Rejent in February 2013. A Bit messy since the machine on the right has just been moved in.

You can see that the shop is much fuller and has much different machines in it. We’ll see what the next couple of years brings, perhaps a new shop?!?

A Simple Die

Just posting some images of a die I made. It came in for servicing and so I decided it’s be prudent to post some images of it for posterity.

A broad view of the simple die, it just simple accepts conduit and punches a couple of slotted holes in it. nothing special.
A broad view of the simple die, it just simple accepts conduit and punches a couple of slotted holes in it. nothing special.
A closer view of the die. As you can see, the punches and dies are both insertable. Since the material it punches is quite thick, the gap is quite large, like .006"
A closer view of the die. As you can see, the punches and dies are both insertable. Since the material it punches is quite thick, the gap is quite large, like .006″

Anyways, nothing too special but I figured I’d keep it here for posterity.

The YIHUA PS-3010D DC Power supply – Quick Review

The glorious PS3010D with its blinking segment and cracked screen. The front panel to the screen was cracked because I flicked it with my fingernail seeing if I could shake it a bit to make the segment work. Nope, just cracked the screen.
The glorious PS3010D with its blinking segment and cracked screen. The front panel to the screen was cracked because I flicked it with my fingernail seeing if I could shake it a bit to make the segment work. Nope, just cracked the screen.

Having needed an adjustable power supply with a bit more current, I decided to buy this guy for about $140 off Ebay. I’ve played around with it a bit and I decided to review it because I’m sure there are a lot of people like me who buy cheap test equipment. You don’t pay much and you can’t expect much, but you can just hope it does the job.

I performed a few tests that you can see below:

So, if you looked at the values shown, you’ll see it works OK. Anyways, here are some pros and cons to this device.


  • Cheap
  • Reasonably effective
  • Knobs and switched feel good
  • Nice high current for a unit like this
  • Nice grill effect over the LED’s make it look like a dot matrix LED
  • Standard size case


  • LOUD LOUD LOUD! Not quite vacuum cleaner loud but louder than anything else in my office.
  • Front power connectors are kind of flimsy and cheap
  • Displayed and measured values do not quite jive
  • Does not have a handle on the top, it’s nice to have a handle on test equipment

Otherwise, the unit works as expected and I’ll write the LED flicker off as a coincedence. It’s too bad that it’s so loud, they could’ve used a different fan or something, becomes a real distraction. If you need something like this that produces 30V at 10A, this may be good purchase.

Another EDM wave form post

Well, at work we have a pair of semi-manual Ram EDM machines. The old CHMER seems to cut very poorly, so I wanted to see what the difference was. Here are a few images from the oscilloscope.

The Mercury FPGA Prototyping unit – Review

The Mercury FPGA from the side
The Mercury FPGA from the side

A few weeks back I got my Mercury FPGA unit and what a nice little unit it is. The device plugs directly into a breadboard and could potentially be used as a drop-in for through hole PCB projects. When I got the unit I was impressed with it’s overall appearance, they sure packed this guy tight.

The Mercury FPGA unit from the side
The Mercury FPGA unit from the side

Having played with this a bit I can see the usefulness of this device. Here are some of the features.

  • A Xilinx XC3S200A-4VQG100C running with a 50Mhz oscillator
  • Complete with proper voltage regulation @ 1.2v and 3.3v
  • Some 5V tolerant IO pins
  • A USB port for direct programming and power from the USB port
  • A separate ADC with 8 channels linked to the FPGA
  • A couple of switches and a few indicator LED’s
  • You can program through the JTAG interface

You can use the Xilinx ISE design tool to synthesize the project and you can use the Mercury software to upload it to the unit. Just based on the little bit I played with it, it seems to be a very useful unit. It’s great for learning (like I am to a degree) and is well designed and labeled on the PCB. There aren’t a lot of bad things I can say about this device except a couple of minor issues.

Issue one would be the sheer size of it. The unit fits on the bread board but with only one spot left on each side to connect things. This is a very minor issue and they did a good job making it as small as it is with as many pins and size of chips it does have, but having only one remaining pin could be an issue.

Issue two is its price. At $65 USD it’s a but more expensive than some other units out there. That said, they are unique in their pcb profile and the developers have to get paid for their time. My serial number was 147 so with such small batches, it’d be difficult to lower the price point. Hopefully it becomes wildly popular and the price can come down to a point where it can be considered a consumable of sorts.

Anyways, aside from my very minor complaints, this device is pretty cool. I can see all kinds of projects benefiting from a DIP style FPGA unit unlike the others which seem to have an arduino style PCB that makes it difficult to include in a project. I recommend that anyone who is going to learn FPGA’s give the Mercury a shot.

The manufacturers website: http://micro-nova.com/mercury

Thanks for reading!

A look at the waveforms from a CNC EDM

I decided to try out my new Hantek DS1060 and get some waveforms from the head of the EDM (Electrical Discharge Machine). The probe was hooked to the head of the machine and the ground was connected to the frame. I only took a few measurements but it may be interesting to some to see what the pulses look like when it’s cutting. This cut was burning at 75us on and 37us off.

This is the waveform while cutting at 75us on and 37us off. 8A current
This is the waveform while cutting at 75us on and 37us off. 8A current

You can see that the voltage doesn’t drop to zero, and there seems to be a dropoff after the ionization path has started to cut the material. These dropoffs after the spike seems to indicate that the path is ionized and current control has kicked in, providing 8 amps. Once the time is up, the current shuts off and then there is a ringing spike, perhaps due to inductance. From there the voltage doesn’t reach zero but probably sits at a continuity testing voltage for a little under the 37us. From what I can tell, 75us is started from when the ionization path is established, and 37us is the time it cuts off the current, event though there is still voltage (and maybe a bit of capacitiance).

A view of the measurements taken from the oscilloscope
A view of the measurements taken from the oscilloscope

The measurements seem to correlate to the settings a bit. The EDM itself is set for a 240V cutting voltage so the VMax of 181V is pretty close. I think those values are a quite flexible, I know that before it cuts at all, the voltage is at approximately 240VDC.

Anyways, I thought this would be interesting to post since some people are into EDM machines. I may take some waveforms from the wire EDM and two more different EDM’s. Here’s a final image of a zoomed in view of the peak.

A wider view of the burning process, the short ringing spike must be a check for proximity
A wider view of the burning process, the short ringing spike must be a check for proximity or from inductance

A quick post, Basic program for day length

Just wrote a little FreeBASIC program for calculating the length of the day and the difference from each. Just enter your latitude and it’ll output a text file for the length of the day and difference from the previous day.

Anyways, it’s not well programmed or anything but the function could be useful for somebody out there. Who knows

daylight download

As a side note, time is in hours.

Dingoo A380 Review

Having bought a bunch of different emulator consoles I have decided to review them for people who may be curious about whether they should buy them or not. In my collection I have the Dingoo A380, JXD S5110, JXD s602 and soo to have the JXD a1000 and a JXD ripoff. I will start with the Dingoo A380 since it is similar to my first one (being the A320) and since it is by far the most popular.

Dingoo a380

The A380 is a mixed bag of features. It plays old console games such as Genesis, Arcade, NES, SNES, Sega Master system, Neo Geo, CPS1 and 2 and various others if you get the modern firmware. It will receive radio and play videos. It will play MP3s and other formats of audio. You can also read E-books and various other things. As with most of these Chinese devices, they try to be everything and do very few things well. But playing games well is something it does well. Here is a Pro-Con list of my impressions of the Dingo A380.


  • Small form factor, fits well in pocket.
  • Simple interface, usable rather quickly. Most sellers will have games already installed but they’re usually in Chinese.
  • Plays GB, GBC, CPS, Genesis, SMS and other custom emulators reasonably well.
  • TF card slot allows up to 32GB, good for MAME roms
  • Allows use of wireless controllers, of course they are proprietary.
  • Nicer aspect ratio of screen for movies. playing old games though the filled screen becomes quite squat.
  • For most things this is the best hand-held emulator out there.
  • No touchscreen. It may be a con for most but I hate touchscreens, I like the nice sturdy screen on the Dingoo.


  • The aforementioned small form factor is also a pain if you have large hands. Playing this can become painful especially with the square corners.
  • L and R buttons are too small and set too far to the outside (for adult hands anyways).
  • There is no button(s) for volume control, this must be done with the software.
  • NES emulation isn’t quite fast enough. Kirby’s Adventure in Dreamland is sluggish but SMB is the same as always
  • SNES emulation is atrocious, even with a updated firmware. Mode 7 games absolutely decimate its performance.
  • TV out is PAL. Not so good if you need NTSC (At least I haven’t seen a setting for it)
  • Very little to configure. changing some stuff that’s bothersome can be impossible.
  • In some emulators, they removed the ability to hotkey savestates.
  • Power button is flimsy, it’ll probably break relatively soon.

Anyways, that is simply my opinion. As of Dec, 2012 the average price on Ebay is about $130 which is what you can get a JXD 7100 for. Mind you, this is probably the best emulator for the older games that you like and it have reasonable battery life. That said, the battery life of about 4 hours pales in comparison to the A320 which seemed to have better emulation and you could get it with Dingux. The new firmware (not from dingoo) is also a must if you like some of the more obscure emulators.

If you like emulators and aren’t scared of the price, I heartily recommend.

A goal challenged robot

I was thinking about cockroaches after seeing some sort of program on the subject. It brought me on to thinking about insect locomotion and the way complex moves are carried out by creatures without a central nervous system. It then started to occur to me that the reason that these creatures (or any other for that matter) function is that there are a great deal of stimuli. An insect’s leg, for instance, has thousands of sensory organs to determine touch, temperature an various other external events that aren’t processed anywhere centrally. The thought the occurred to me about the notion of how a nervous system might work. Hence my latest, yet ugly, creation. The Roboto v2.

Roboto V2. from the front
This is the robot from the front. Currently it has 6 ultrasonic range sensors. This was the best thing to test my idea.

I had a frame for a robot I had already assembled and really didn’t get anywhere with it until I had this idea. Basically the idea is to have a matrix of variables, in this case a 10×10 struct array. Sensors are ‘bound’ to certain segments of the matrix. The matrix elements also communicate with the adjacent nodes to relay positive or negative stimuli. These stimuli make their way to the motor controls which are bound to other matrix nodes, in my case, elements several nodes away on opposite sides of the grid. The values expressed in the node are translated into motor movement.

Roboto V2.0 from the top, A tremendous jumble of wires.

What I have right now is functioning better than I hoped. I made close proximity ‘painful’ and moving forward ‘pleasurable’. A close proximity on the side will cause pain on the same side. Currently the robot seems to find open areas but doesn’t stay in them. I did fudge some things which are.

  • Output to the motors is kind of jury-rigged to disallow stopping by ensuring that at least one wheel is at maximum motion based on a weighted average.
  • the sensory input is weighted at the nodes. This was needed simply to make it function correctly.
  • I have a constant ‘pleasure’ value plugged in to make the robot strive to move forward. otherwise it would probably just stay in one place.
Here’s a video of it in action, doesn’t do a lot but I think it’s neat because I can’t predict it’s reaction despite the fact that it’s perfectly logical.

Well, I’m going to try some other things and add more stimuli like IR sensors, compass, accelerometer and a gyro. We’ll see if I can get something interesting out of it. An in case anyone is wondering about the build here’s a point by point list of what I used.

  • Arduino Mega2560
  • A robot chassis that I bought off EBay. It’s not bad.
  • Built the motor driver board myself with an SN75441one and a 5A linear LDO reg.
  • 7.4v LiPo battery, 850mah for direct drive to the motors
  • A little cheap bread board
  • and LED-KEY module, based off the TM1638, very handy modules
  • lots of male to female wires!
Anyways, Let’s see how it goes.