Archive for the ‘Electronics’ Category.
I just bought an ESD mat for my workbench. ESD mat is great when working with sensitive electronics components as it safely dissipates any charge built-up to the ground via its dissipative surface through the attached grounding wire. Continue reading ‘ESD Mat For My Workbench’ »
I had wanted to make a spot welder for a while. Most of the DIY spot welders use a momentary switch the primary side of the microwave oven transformer (MOT). Due to the simplicity of this design, it is very simple to make. This design however, has some inherent safety issues as the momentary switch is typically within reaching distance of the operator (unless a foot switch is used) and inadequate insulation could increase electric shock risk. Further more, the current flowing through the primary winding can significantly exceed the current rating of the switch and cause the switch to fail. Due to the inductive nature of the winding, the switch can sometimes arc over and pose significant risk to the operator. Continue reading ‘Dual Purpose Spot Welder With Pulse Duration Control’ »
I recently upgraded my home phone system and thus was left with a couple of old Uniden DCT648-2 handsets. Most of the components inside are probably not salvageable but these handsets use 3×16 character LCDs, so it would be nice if I could reuse them in my other projects. Continue reading ‘Reverse Engineering a Uniden Cordlessphone LCD’ »
I got a Wavetek 395 arbitrary waveform generator (AWG) last year. Unlike my other equipment (such as HP 8566B, HP 5350B, HP 8642B and Racal Dana 1992) which all came with high stability ovenized crystal oscillators, the Wavetek 395 only comes with a 100ppm crystal. While the stock timebase is perfectly fine for all but the most serious measurements, I decided to upgrade it to an oven controlled crystal oscillator (OCXO) as I happen to have a Vectron CO-717B58N lying around. Continue reading ‘Wavetek 395 Timebase Upgrade’ »
I picked up an HP 7044A X-Y recorder on eBay recently. This one was made in the early 1980’s and by today’s technology standard it is rather ancient. And because of this, it is very easy to interface with as the input is completely analog. My plan was to do some experiments down the road using the X-Y movements capability of this HP recorder. Continue reading ‘HP 7044A X-Y Recorder Teardown, Lorenz Attractor’ »
Till recently, I have been using custom circuitry whenever I needed to backup some firmware. But the process was rather tedious as for each kind of EPROM or EEPROM I needed to study the protocol and timing requirements and then come up with the required circuitry on a breadboard. And wiring can easily become an issue with a high pin-count chip. So I finally got myself a proper EPROM programmer (it’s a TL866A) along with a $15 generic UV EPROM eraser so I could program EPROM/EEPROM’s quickly. While it was fun to build a programmer circuit each time, I think the effort can be put into something more useful. Continue reading ‘Cheap UV EPROM Eraser Teardown and Spectrum Analysis’ »
I got this broken Beats Solo2 BT wireless headphone from one of my colleagues. In fact, it was broken once before around two years ago and I fixed it for him back then. The issue was because of a broken signal wire due to repeated flexing of the collapsible headphone band. This time around though, I am not going to fix it although I suspect that the cause remains the same. In fact, quite a few of my friends with the same Beats headphones had experienced similar problems. So I wanted to take it apart and take a closer look inside. A video of this teardown can be found towards the end of this post. Continue reading ‘Beats Solo Bluetooth Headphone Teardown’ »
In my previous blog posts, I did a teardown of the Symmetricom/Datum 8040 Rubidium frequency standard and modified the 1PPS output by expanding the pulse width from just around 10µs to roughly 50% duty cycle. There were some questions regarding the clock jitter introduced by the 555 monostable circuit. So let’s take a more detailed look in this post. Continue reading ‘Jitter Measurement of the Pulse Width Expanded 1PPS Output’ »
Last time, I did a teardown of the Datum 8040 Rudidium standard. As I discussed, the 8040 has a 1PPS output but the pulse width is very short, at around 20µs. In this blog post, let us take a look at how to extend this 20µs pulse to make the 1PPS output symmetrical. As usual, a video is included towards the end. Continue reading ‘Datum/Symmetricom 8040 Rubidium Standard Modifications’ »
I finally got my hands on a Rubidium frequency standard. I have been wanting to get one of these for my lab for quite some time now but have not encountered a good one at a reasonable price. Most rubidium oscillator modules on the second hand market these days come from decommissioned equipment used in cell towers. A good used lab grade rubidium standard is even more expensive. Continue reading ‘Datum/Symmetricom 8040 Rubidium Frequency Standard Teardown’ »
I picked up a non-working Racal-Dana 1992 Frequency Counter on eBay a few weeks ago. The symptom is that only channel C seems to work correctly and neither channel A or channel B produces any measurements. Since the majority of circuitry is shared among all three channels, it is most likely that the fault is localized within channel A and/or channel B. In this blog post I included many teardown pictures taken during the repair and a video detailing the process is included towards the end. Continue reading ‘Teardown and Repair of a Racal-Dana 1992 Frequency Counter’ »
I got myself an HP 5350B microwave counter a couple of years ago and did a teardown of it. The backlight on the LCD is pretty weak and does not provide much contrast however. So I thought I would upgrade the backlight with a few white LEDs and see if I can make the display easier to read. Continue reading ‘HP 5350B Backlight Upgrade’ »
I bought a couple of IXYS linear MOSFETs (IXTK90N25L2) a while ago to test their capabilities when used as electronic load, and the result was quite impressive. So I decided to build another electronic load using both MOSFETs. As you can see in the video towards the end, this electronic load can sink more than 100 Amps of current while dissipating more than 400W continuously and can withstand more than 1kW of power dissipation in pulsed operation mode. Continue reading ‘A 400W (1kW Peak) 100A Electronic Load Using Linear MOSFETs’ »
In this blog post, I will show you a simple hardware hack to make your mouse capable of rapid firing (or automatic continuous clicking). Of course you can always resort to software mods to achieve the same goal, but admittedly doing so in hardware is nevertheless more fun and as a bonus you also get an extra button. A video demonstrating this hack can be found towards the end. Continue reading ‘Hacking Your Mouse for Rapid Firing’ »
I just picked up a charger along with a couple of NP-FW50 spare batteries for my new Sony Alpha A6000 mirrorless digital camera. The Sony branded charger is ridiculously expensive, so I opted for an aftermarket Vivitar branded one (VIV-QCB-104), which retails for under $10. The charger is rated at 8.4V with maximum charging current of 600mA. Spec-wise, it looks fine for the NP-FW50 1Ah 7.4V battery pack. Continue reading ‘Teardown of a Vivitar Rapid Battery Charger’ »