diy solder paste dispenser

DIY Solder Paste Dispenser

In this post, I’ll show my DIY solder paste dispenser. It’s powered by a 12V adapter and can be operated by a footswitch(connected via banana connectors). It uses a small membrane air pump/compressor to dispense the solder paste/flux. Additionally, there is a solenoid air valve connected to the airline so the pressure can be released after you let go of the footswitch which prevents the solder paste or flux from oozing out. The pump and valve timing is controlled through a relay module by an attiny45 microcontroller.

Computer PSU DIY Power Supply

DIY Power Supply From An Old Computer PSU

In this post, I’ll show a DIY power supply I made from an old computer PSU. This is a great way to get a fairly powerful lab power supply with a range of different voltages for cheap. I used a breakout board I bought online as it’s much quicker and simpler than drilling holes for all the connectors into the case and then soldering all the wires.

dead GPU fix by heating

How To Revive A Dead GPU

In this post, I’ll show you how I fixed my dead GPU by simply heating it up. Some time ago the GPU in my old computer died(black screen). I managed to repair it by simply slowly heating it up, keeping up the heat for some time and then slowly lowering the temperature back down again. As my previous PC was quite old when this happened I got myself a new one and haven’t used the old PC very much since then. So I don’t know how much longer the fixed GPU might have lasted after that.

DIY 9V Battery Power Supply

9V Battery Power Supply

In this post, I’ll show a 9V battery portable power supply I made quite a few years ago by originally following this tutorial. This particular power supply uses a voltage regulator(LM317) to drop down the voltage and dissipate the energy as heat. This means it becomes inefficient at higher currents. So it is most useful to power things that don’t require a lot of power.

ALU the A and B Registers

8-Bit Computer ALU And The Flags Register

In this post, I will talk about the ALU and the flags register of my 8-bit computer. The arithmetical logical unit(ALU) is where all the computation happens in a computer. The ALU of this computer is very simple and only has the option to add or subtract numbers. So something like multiplication would have to be implemented in software.  The flags register stores the Carry(a carry occurs) and Is Zero(the result is a zero) flags that it receieves from the ALU. 

button debounce module

8-Bit Computer Button Debouncing

In this post, we’ll take a look at the button debounce module of my 8-bit computer. Ben used a 555 timer in his clock module to make a delay to debounce the button. I took a different approach. I took the 50 MHz input from the crystal oscillator and lowered the frequency by using another clock module. This way I have another slower clock signal independent from the main clock. This slow frequency is then fed into the debounce modules.

clock module

8-Bit Computer Clock Module

In this post, we’ll take a look at the clock module of my 8-bit computer. Ben used a 555 timer in his clock module to generate the clock signal for his breadboard computer. The approach I took is a bit different. The DE0 Nano FPGA development board has an onboard 50 MHz crystal oscillator connected to one of the pins of the FPGA. This is where we can get our clock signal from. The problem is that the frequency is way too high for the computer and needs to be lowered. This can be accomplished by dividing the frequency using a frequency divider(which is esentially just a ripple-carry counter) or by using a PLL(phase locked loop).

program counter ripple carrycarry

8-Bit Computer Program Counter

In this post, we’ll take a look at the program counter of my 8-bit computer. The PC(program counter) is used to store the memory address of the next instruction to be executed. After the instruction was executed it the value in the PC will be incremented by one, therefore, pointing at the next memory address that contains the next instruction. The PC is almost identical in construction to the microinstruction counter as both of them are just ripple-carry counters.

control unit and microinstruction counter

8-Bit Computer Control Unit

In this post, we’ll take a look at the control unit of my 8-bit computer. Ben used an EEPROM to make the control unit in his computer. This is a quite clever approach if you are building your computer on a breadboard as it drastically decreases the complexity, amount of components and space needed. But in my case, it was much easier to just implement the control unit using discrete logic gates. 

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