Circuits on PCB Isolation

Repairing and Adding Bluetooth to an 80’s – 90’s AC Delco Radio

Wed, 17 Jun 2020 00:00:00 +0000

AC Delco Model 16131355

This post details the repair of a early 1991 AC Delco stereo. AC Delco made many variants of this stereo for both Chevrolet and GM cars, trucks, and vans from the early 80’s to the mid-90’s. While many of the stereos have more or less features (cassette players, radio presets, etc), the amplifier section of the radio is fairly standard and unchanged.

Internal Pinout and Schematic

Swapping LEDs and PCB in a Dimmable Nightlight

Mon, 11 May 2020 00:00:00 +0000

I’ve looked and been unsuccessful in finding household nightlights that meet my criteria:

auto on/off
dimmable
1800K CCT
decent CRI
uniform illumination
no flickering
power efficient

The closest I found was this nightlight. I like everything about it except the 3000K CCT. I believe it’s a bit too cool for a nightlight.

I ended up swapping the 3000K LEDs for 2200K LEDs. I would have preferred 1800K, but was unable to source them on Digikey.

Octopart API Pricing Scheme

Thu, 06 Jun 2019 00:00:00 +0000

Octopart, the search engine for electronic and industrial parts, doesn’t post the pricing for their API on their website. There’s a bit of irony, since Octopart scrapes pricing from sites like Digikey, who also tries to hide their pricing.

The Octopart API is a great resource for pricing BOMs. KiCost is a great example of tool that uses the Octopart API (although KiCost has moved away from Octopart due to the paywall).

As of June 2019, the Octopart API is as follows:

How To Spot a Counterfeit or Refurbished Motorola Razr V3

Thu, 04 Apr 2019 00:00:00 +0000

Note - There are many versions of the Motorola Razr, each with subtle differences. Even similar version have differences between countries. Not all of the differences of this counterfeit/refurbished Razr will apply to your Razr!

This applies specifically to the Motorola Razr V3, but you can find similar discrepancies on a Razr V2 or V3i.

If you have a feeling the phone is fake, that’s a good indicator that it is.

Motorola Razr V3: Real vs Counterfeit Teardown

Sun, 31 Mar 2019 00:00:00 +0000

Left- Authentic Razr V3, Right - Counterfeit Razr V3

I recently bought a Razr V3 on eBay. The listing below shows that it is made by Motorola. The pictures are of an authentic Razr. However I received a counterfeit Razr.

PS - I wrote a quick guide on spotting counterfeit Motorola Razr V3’s (without disassembly).

If the phone would have worked, I wouldn’t have cared. But it wouldn’t get a signal with my SIM, so I complained and got a refund.

Reflow Toaster Oven Build

Fri, 14 Apr 2017 00:00:00 +0000

This is a conversion of a convection toaster oven into a SMD reflow oven. I took a standard toaster oven then added insulation, ControlLeo2 controller, temperature sensor, cooling fan, and a front panel. It has excellent thermal properties and follows a reflow profile well.

I bought the ControlLeo2for the reflow controller. It features PID control and is overall good. Still has shortcomings. I had to heavily modify it to make it fit in the front panel. A different LCD (8×2 or 8×4) and a new PCB layout would make this board slim enough to fit. Additionally, I had some issues with LCD corruption and had to modify the software. I am also disappointed with the lack of PID control for the cooling fan.

Simple Automatic Volume Control with Arduino

Tue, 20 Sep 2016 00:00:00 +0000

This was for a pair of outdoor speakers in front of KMNR, my college radio station. KMNR was receiving complaints for having the music too loud at night.

An Arduino checks clock and adjusts volume using digital potentiometers This post is a walkthrough of the design and implementation.

Design

I interfaced an Arduino with a RTC (real time clock) to get the time. The RTC is Maxim’s DS1307 and it should last 17 years on it’s backup battery. It communicates over I2C and you can find already written code here.

Designing a Single Op-Amp Triangle Wave Generator

Sun, 11 Sep 2016 00:00:00 +0000

While this is not my design, this is my analysis and derivations.

I used this in my sound reactive lighting project. I had only one op-amp to spare for a triangle wave generator, so I couldn’t use the popular two op-amp design.

For those who are not interested in the details, you can find the final formulas in an example here.

Overview

view this circuit simulation here

LED Sound Reactor – All Analog Approach

Fri, 02 Sep 2016 00:00:00 +0000

In the winter of 2013, LED strip lighting hit its tipping point - a big rise in popularity.

A year beforehand, in 2012, I had an idea to build a controller for LED strip lighting. A sound reactive LED controller

to make the lights get brighter on the bass notes. Biggest problem - I didn’t know how to make one.

I finally started getting comfortable with electronics in 2014.

Motorcycle Brake/Turn Light PCB

Sun, 21 Aug 2016 00:00:00 +0000

A stranger off eBay got me pulled over, from across the world.

I have a 1983 Kawasaki CSR 305 that has a hint of a cafe racer. For the look, I replaced the stock brake and turn lights with a LED brake/turn light combo from eBay. It was manufactured overseas, very cheaply.

typical cheap brake/turn light

Something failed and the lights went out…at night…while riding. This upset the local authorities.

Best Shortcuts in CircuitMaker by Altium

Thu, 30 Jun 2016 00:00:00 +0000

Here’s a list of the most useful shortcuts in CM - more graphical and intuitive than the built in shortcut list (Ribbon Bar->View->Shortcuts).

Above - Shortcut List Location

Pro Tip: When the tools aren’t working correctly, press ESC a few times.

Schematic Shortcuts

Crtl+Scroll	Zoom
Center Button - Click Hold and Drag	Zoom
Pg Up/Down	Zoom (Great for laptops)
Right Button - Click Hold Drag	Pan
Ctrl+A	Select A ll
Crtl+C	C opy
Ctrl+X	Cut
Ctrl+V	Paste
Ctrl+D	D uplicate
W	W ire (for opening wiring tool)
Space	Change Wiring Path - Only works when wiring
Shift+Space	Change Wiring Angles - Only works when wiring
Space	Rotate Selected Object
Tab or Double Click	Edit Properties of selected object
G	Toggle G rid Size (look in bottom left-hand corner)
Z	Add Ground
V	Add V CC (press TAB to quickly change net name)
T	T ext (press TAB to change text)
N	N et Label (press TAB to change text)
C	Place C omponent
X	Flip left/right (X -Axis)
Y	Flip up/down (Y -Axis)
Esc	E xit Tool
Ctrl+Tab	Go to Next Tab
Ctrl+Shift+Tab	Go to Previous Tab

PCB Shortcuts

Crtl+Scroll	Zoom
Center Button - Click Hold and Drag	Zoom
Pg Up/Down	Zoom (Great for laptops)
Shift+Pg Up/Down	Precise Zoom (Great for laptops)
Right Button - Click Hold Drag	Pan
Esc	Exit Tool (so very useful)
Ctrl+A	Select All
Crtl+C	Copy
Ctrl+X	Cut
Ctrl+V	Paste
R	Route Trace
Space	Change Routing Path - Only works when routing
Shift+Space	Change Routing Angles - Only works when routing
Space	Rotate Selected Object
G	Toggle Grid Size (look in bottom left-hand corner)
Shift+S	Single Layer View (Toggle visibility of all layers except for the active layer)
Backspace	Undo Trace Segements of selected trace
Tab or Double Click	Edit Properties of selected object

Have a favorite not listed? Leave it in the comments below.