Decoding Sensor RS485 Output with an Oscilloscope

I was at a client's place, trying to connect a humidity and temperature sensor to our equipment. The sensor has a RS485 interface, and the manual says the default speed is 4800,7E1. The pink wire is RS485-A and the grey wire is RS485-B. I connected it to a Moxa Nport 5230-T, and configured the port settings. This is what the sensor had to say: I had similar results when using a USB RS422/RS485 adapter on my laptop too. The sensor emits that junk a second or so on power up. There is al...

My Tab S Keyboard Broke!

So there I was done with with my late night youtube surfing when I put my tablet back in its keyboard-case and ... something felt weird. I switched on the bedroom lights and looked down at my tablet and found the clasp had broken! Now this tablet is over 4 years old (https://blog.shahada.abubakar.net/post/replacement-toy-galaxy-tab-s-yeah-not-an-s2) but it has a great design. Why do I say this? To begin with the tablet has a 16:10 screen ratio, which is great for watching wide screen conte...

Router Replacement: Mikrotik RB4011 and TIME DotCom 1Gbps Internet Service

I bought a Mikrotik RB4011 router to replace the router for my TimeDotCom Fiber Internet service. Mostly for fun education. ☺ Actually there were some issues bugging me with the TIME supplied DIR-882 router. It's a speedy router, but I couldn't get NAT loopback to work, the DNS lookups with Google DNS seems sluggish, and I wanted to monitor my traffic using SNMP. Although the firmware is customized for TIME, TIME's support referred me to D-Link for questions regarding the router. But th...

Changing my ISP : Telekom Malaysia's UniFi → TIME Home Fibre Internet, and Do You Really Need 1Gbps?

Since I live in a 20-year old apartment, Telekom Malaysia's UniFi Fiber-To-The-Home is delivered only to the riser room in the basement of my building ... from there the internet service is carried into my unit using the existing regular copper cables (using VDSL technology). The copper cabling is the bottleneck here and limits the speed offered by Telekom Malaysia to 30Mbps. When I first moved in, I started with 10Mbps UniFi, and then upgraded to the UniFi Advance 30Mbps + Aneka (Q2 2016 C...

DPH-5005 Benchtop Power Supply Project

Up till now I have been using 12V and 5V power supply units on my desk to power various stuff I am tinkering with, from data loggers to sensors and so on. As I didn't like the open power terminal connectors, I 3D-printed an enclosure for them. I also took the opportunity to make multiple output terminals, so I can easily connect multiple devices simultaneously. Each output terminal has its own switch and LED and also a fuse. This is fine and good for working with stuff that works. But I've b...

Lightbulb Review!

The Energy Saver CFL lightbulbs in my apartment are starting to die. Some of them have been around for over 5 years so this is to be expected. With the prices of LED bulbs dropping, is it time to switch? I regularly buy my CFL bulbs from Camar Letrik in Taman Paramount where they sell the CFL bulbs for MYR9 (USD2.19). That's a lot cheaper than the MYR 20+ (USD4.86+) the supermarkets are selling them for. The question is: can I get LED bulbs for comparable prices now ? The 18W Energy Saver...

Samsung Tab S 10.5 Battery Replacement

So there I was minding my own business in a McCafe when I realised that my Tab S 10.5 tablet was not quite sitting flat on the table. Tapping on the sides of the screens would make the tablet spin. Feeling around the back of the tablet I discovered there was a slight bulge on the rear of casing ... ... which is a sign that I have a battery that is about to die. Woah! Maybe it is time to get a new tablet? How about the newly launched Tab S4: To be honest I was quite ready to upgrade out of ...

How To Get Lines Painted On A Road

The road leading to my apartment was resurfaced a few months ago. One of the speedbumps along it however, did not have its markings redrawn, and as a result, was simply a dangerous hump on the road. Someone tried spray-painting some stripes across it, but it was hardly effective. I've forgotten about it enough to have had to brake at the last minute so many times, that I decided to do something about it. But how do you go about getting lines painted on a road? The roads in my area fall un...

Adding a Raspberry Pi Zero W and CNC.JS to the 3018 "Woodpecker" CNC Router

I attached a Raspberry Pi Zero W running CNCJS software to my 3018 "Woodpecker" CNC machine. CNCJS is a web-based gcode feeder than can be used to control the CNC hardware. Being web-based, I can now control the CNC wirelessly from anywhere on my home network, using my desktop pc, tablet or phone. Here are my build notes. Setting Up The Raspberry Pi Zero W I started by installing the 2018-06-27 version of Raspbian Stretch Lite onto a MicroSD card using Etcher. Next, I powered up the Pi Ze...

Adding End-Stops / Limit Switches to the 3018 "Woodpecker" CNC Router

In its original design, the 3018 "Woodpecker" CNC Router, a cheap entry-level unit found on eBay and AliExpress, will happily tell the stepper motors to keep moving along the axis, even if the work bed or spindle carrier is bumping against the end of its range of movement. This is because the router doesn't actually have any absolute measurement of where it's current position on the axis is. It assumes it is at the "home" position (machine coordinates 0,0) whenever it is powered on, and will ...