Tag Archives: DIY

Electronics, Experimental

DIY UPDI PROGRAMMER

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#117 A DIY UPDI plug and play board

Making fast and crude but reliable programmers

When getting into the new ATtiny series (tinyAVR-0 tinyAVR-1 tinyAVR-2 IC’s) of microcontrollers a few years ago I noticed how easy it had become to program them with only a few extra components.

I started out with just a 4.7k resistor and a cheap CH340 programmer. Then 3 wire hook-ups later I could easily program my IC’s. The only downside was that I had to sacrifice the UPDI pin to the dedicated Pin gods.. so I couldn’t use that pin unless I wanted to make my life more difficult.

Well this was okey for me and ever since I always have the UPDI pin open only for programming. So all my designs incorporate this principal. If I really need more pins I would use an affordable IO expander IC.

Now with that being said it’s all good and well programming with a mini rats nest… but I wanted to create a simple plug and play DIY programmer with commonly available parts and plug and play compatibility.

So I came up with a small circuit that’s easy to build on stripboard. I created a few versions over the years. Since I was the only one using this contraption I didn’t think of creating a professionally made PCB but that will come in future..

Front of the stripboard
Back of the stripboard

How do I use this?

Basically I solder the SMD package ATtiny to a suitable breakout PCB then I plug the ATtiny breakout PCB into my programmers female headers making sure the orientation is correct and presto all I need to do is upload my firmware. Then I can just remove the PCB and Plug it into my project

Simple and to the point… plus it’s been working for years.

Electronics, Experimental

DIY LORA MODULE

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#115 Making A DIY LoRa Module

2x DIY LoRa RFM95W modules with adapter boards.

When taking a closer look at the DIY aspect of lora I wanted to test LoRa peer to peer.. E.G multiple peers to one peer (NOT LoRa WAN) I noticed that the actual radio PCB is difficult to use when going the traditional through hole way… adapter boards do exist but are few and far between at least in SA. you can make your own for manufacture but then rather create your entire product PCB for manufacture.

Even with this drawback I was able to source old adapters for one of the very firs modules the: RFM95W. In South Africa we are mostly using 868Mhz although 433Mhz modules are around I don’t see them being super common in terms of LoRa modules.

The modules I used have a footprint for adding a female SMA connecter for easy antenna connecting.

Parts used:

  • 2x RFM95W 868Mhz LoRa module transceiver
  • 2x 3.3v active buzzer
  • 2x 1 pole dip switch
  • 2x TP4056 module with protection ICs
  • 2x ATtiny404 MCU
  • 2x NCV8163 3.3V LDO
  • 2x SSD1306 128×32 OLED
  • 2x 2pin 2.5mm JST battery connector
  • 2x Headers and jumpers
  • 2x 13400 3.7V 550mAh
  • 2x 10k resistors
  • 2x 220R resistors
  • 2x SOIC to DIP adapter PCB
  • 2x BC547 transistors
  • Some 0.9mm tin plated copper wire
  • Some 0.255mm PVC insulated wire
Soldering made slightly easier…

After checking the PCB I commenced with testing the devices. Unfortunately the test area has largely mountains terrain
the signal works really well and penetrates better through foliage on the mountains terrain but once there is a full on mountain in the way the signal stops. so in this retrospect the devices are better then a radio which was quite interesting but makes sense because data is being sent and uses less bandwidth then interpreting voice audio. Also the error checking for LoRa helps a lot.

Some more pros for the LoRa is that its a transceiver out of the box with RSSI functions included. Also for increased range and/or quality the spreading factor and signal bandwidth can be adjusted.

Although there’s many pros regarding LoRa I still tend to use simple 433.92 RF modules without issue at least in my situation with rural areas under about 3KM at and given point.

So it really becomes more of a cost factor than anything else. Although I’m happy selling a custom LoRa product for compatibility with LoRa WAN or some other requirement with a similar principal. Plain old generic RF is still cool in my book.

Back of one of the PCBs

Electronics

NEMTEK REMOTE CONTROL

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#82 Remote control and monitoring NEMTEK LCD18

During summer there’s been a ton of rain this year and my electric fence alarm keeps going off
The 2 main reasons are lots of water and crazy grass growth around the property.
It’s been impossible to use weed killer because it rains so often it’s all just washed away.

So I decided to install a remote switch as well as a sensor to alert me if the siren is blaring off.

For the switch I used a SONOF RE5V1C DC powered relay. This device costs under R100.00 and can be powered by 5v DC, the switch can handle 10A of DC or SV loads up to 240V.

SONOF RE5V1C

For the alarm siren sensor I used an SONOFF DW2 Wi-Fi wireless door/window sensor. I de-soldered the magnetic switch and just soldered 2 wires to the pads. Now when the siren goes off a 12v relay will close the relay and the DW2 will report a closed event. The DW2 cost R115.00

SONOFF DW2 Wi-Fi

The great thing about this project is the price and the usage of the SONOFF software and MQTT service. There is no need to create my own firmware or MQTT software by using these affordable SONOFF products.

Electronics, Experimental

CREATING A DIY RELAY

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#81 Building a 12v relay on a cheap PCB board

Completed relay

While working on one of my projects I needed a 12v relay unfortunately I did not have one on hand and was not about to pay for 1 relay plus shipping.

Luckily I had all the components at hand:

1 green and 1 red led
2x 470 ohm resistors
1x 1k resistor
1x 1N4007 diode
1x bc547 transistor
1x 12v relay
Some solid alarm wire
Very cheap rectangular PCB

For a 5 volt version just replace with a 5v relay and 2x 100 ohm resistors for the LEDs.

Unfortunately the PCB I had was very cheap and I could not fit the screw terminals I had so I had to squeeze them in.
I also used thin alarm wire as i did not need to switch high amps but luckily everything worked out in the end.

It was a bit messy but next time I will use a better quality PCB that doesn’t burn tracks when making solder bridge tracks.

The BC547 also allows switching with 3.3 volt logic but remember to supply the 12v

Experimental

MIG WELD ATTEMPT

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#72 Learning to MIG weld

While living on the farm I couldn’t help but notice the necessity of a welder. From fixing gates to fixing vehicles and setting up fences. Creating burglar guards and security gates. These are all musts especially in the dangerous rural areas in South Africa.

So I endeavored on my welding journey, looking for the best welder for a beginner. After months of research I decided on the MAC AFRIC 180 A IGBT (MIG & MMA) Industrial welding machine. It has (120A=100%, 150A=60%, 180A=35% ) duty cycles.







I purchased the machine from Adendorff

After setting up and practicing a few beads I got the hang of it, Just need to improve my bead and reduce splatter. More practice.

My first bead… quite a hot mess.
Second bead (on the other side) much better but still needs work…




Very happy with this option as a first timer welding steel.

Electronics

DIY VEROBOARD TOOL

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#64 DIY VEROBOARD TOOL

While working with electronics one of the easiest PCB boards I have found to work with is the horizontal stripboard. When using this type of board it is important to cut the tracks in a reliable fashion with adequate clearance veroboard cutting tool by Vero. This is a staple tool in the art of PCB prototyping but… it can be unnecessarily expensive. So I created a simple DIY version.

Factory made version.

Here is a small explanation of the process. Also take a look at this link which explains which are the best drill bits for a DIY veroboard trace cutter.

soft broomstick handle with 3.5mm drill bit epoxied in place.

Use a broom handle (or soft wood in a cylindrical shape) a 3.5mm drill bit and some epoxy.

In my case the price was 86.4% cheaper then buying one from the shop in South Africa.

Let the epoxy set in a smooth position (or as smooth as I could get it…)

Arduino, Electronics

UNO ATTINY85 PROGRAMMER

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#38 DIY ARDUINO UNO ATTINY85 PROGRAMMER

Sometimes an Arduino pro mini is just not small enough for an electronics project. Enter the Arduino ATTINY85, this MCU comes in an extremely small package. It has only 8 pins and works with 5v.

Below are the specs of this microcontroller:

  • AVR MCU, 8K FLASH, 512B RAM, SPI
  • Controller Family/Series:AVR Tiny
  • Core Size:8bit
  • No. of I/O’s:6
  • Program Memory Size:8KB
  • EEPROM Memory Size:512Byte
  • RAM Memory Size:512Byte
  • CPU Speed: 8/16 MHz internal clock, up to 20MHz external clock
  • No. of Timers:2
  • Peripherals:ADC, Comparator
  • No. of PWM Channels:4
  • Digital IC Case Style:DIP
  • Supply Voltage Range:2.7V to 5.5V
  • Operating Temperature Range:-40°C to +85°C
  • No. of Pins:8

This is great and all but its a hassle to program the board unless you buy a dedicated programmer (expensive in SA) or if you’re happy to use a messy breadboard every time you want to program. So I decided to make a very crude but effective programming shield for my Arduino UNO.