Low Cost IC Trainer Kit


Bugged by the kind of trainer kits we get in college, I decided to make my own digital circuit design lab. It basically required two main parts – an astable and a monostable multivibrator. This was needed to run sequential circuits. The rest of the circuitry is basically connections to output LEDs and a power supply for which I used an adapter available cheaply at any electrical shop. The base was made using switch boards. I feel a wooden board would be a better option though. Before telling you how you could make one for yourself, here’s what the kit I made looks like:

The kits most colleges here use have spring pins which can get very irritating. Using two bread-boards seemed a better option. As you can see, there are two regulator knobs. One is used to vary the frequency of the astable.  The one below it varies the DC input.
Timer Circuits

Before I begin, here’s the site where I got the astable and monostable circuits:

The circuits are pretty simple to construct on a general purpose PCB. Once you are done, you’ll have to connect these in parallel with the other sections to the DC supply. However, the astable’s frequency must be variable. You should have either 1Hz, 10Hz, 100Hz or 1KHz. To do this, I used 4 capacitors and a selector knob to switch between these values. Make sure that you do not fix the tactile switches directly to the PCB. Connect them to wires that are long enough. These switches will have to show up on the trainer kit’s base. The RC components for the two circuits are:
Astable:
R1 = 1KΩ
R2 = 680KΩ
C   = 1µF, 100nF, 10nF, 1nF
Here’s a photo of the astable circuit:

Monostable:
R1 = 100K
C   = 10µF
I made a small change or rather, an addition to the monostable circuit. I added a NOT gate to the output. This way I can get both positive and negative pulses for my sequential circuits. Here’s what the monostable looks like:

Output LED Circuit

Once you’re done with those two circuits, you’ll have to fix the output LEDs… these are basically 16 green LEDs, each connected to a 1KΩ resistor at the cathode. The resistors are given a common ground connection. The anode of the LEDs are connected to the outputs of the digital circuit (which you would construct on the trainer). The circuit for this section is:



You would also want to put those LEDs in holders before you solder them to the resistors. Here are some pics:


Input Power

I used an adapter which gives an output of 12V DC and a potentiometer to vary this voltage. You’ll usually require a voltage supply of 5V DC for most of your circuits. This supply is even given to the Vcc inputs of the timer circuits. A connection is also given to the bread-boards like this:

As seen later, there are alternate Vcc and ground connections in the kit.

Making The Base For The Trainer

Now that most of the circuitry is done, we’ll have to set up the base. This requires drilling and filing. So make sure you have a drilling machine, a flat file and a round file. Since I’m writing this article after finishing the trainer, I don’t have pics of the base once the required holes have been drilled and filed.Lets start with the holes required for the output LEDs. Use a drill bit thats large enough to make a hole that lets the LED holder fit through. You will have to make 16 of these holes. Right below each LED, you will need to drill holes for wires that connect to the anodes of the LEDs. These wires are connected to joints where you can make connections to the LEDs as outputs to your circuits. Once you are done with this section, you should have something like this:

Next we will have to make connections for the timer circuits. You’ll need a square hole for each tactile switch. I did this by drilling a tiny hole and then filing it to get the square hole. If you have tools to cut directly, then that’ll be great. Again, you’ll need holes for wires which then go to the joints just like the LEDs. I have also given connections to Vcc and ground. This was basically to measure Vcc values using a multimeter while changing its value. This is what you should have:

Now we need holes drilled for the potentiometer, the frequency selector and a square one for the switch. I got the square hole again by drilling followed by filing (which took a very long time). Two more holes need to be drilled for wires that go to the adapter and that finishes most of our work. This is what the base should look like:

To finish the top of the base, fix the two (or more if you want) bread-boards). You’ll need to drill two tiny holes for wires that give Vcc and ground connections to the bread-boards as I showed above. You’re base should now look like this:

You could now put labels for the various sections and make an small dock for the adapter. For this I used two left over spacers (we’ll require these for the lower part of the base) and a velcro strap:

Now we move on to the bottom section of the base. This can be done in about 10 minutes easily. You just need to drill a few holes and put some screws. You’ll have to put spacers at each corner and drill holes at the top of the base as well for screws to join with these spacers (It would be a good idea to drill these corner holes together in the beginning itself so that they are aligned properly). These screws Ive put in the middle hold the PCBs in place. These are optional. Here’s what the lower section of the base looks like:

In the picture above, you can see that I’ve fixed plastic legs for the base. These go right below the spacers. Now we’ll have to put the entire thing together. Fix the top of the base to the spacers and your trainer kit should be done. I’ll end with a pic of the trainer being used for a timer circuit:

The entire kit cost me around Rs. 500. Would have been cheaper if I used wood for the base since the switch boards itself were around Rs. 200. Hope you liked the trainer kit. Please post comments and suggestions or tell me if I’ve missed out on anything. Thanks for reading :-).

Low Cost IC Trainer Kit

Bugged by the kind of trainer kits we get in college, I decided to make my own digital circuit design lab. It basically required two main parts – an astable and a monostable multivibrator. This was needed to run sequential circuits. The rest of the circuitry is basically connections to output LEDs and a power supply for which I used an adapter available cheaply at any electrical shop. The base was made using switch boards. I feel a wooden board would be a better option though. Before telling you how you could make one for yourself, here’s what the kit I made looks like:

The kits most colleges here use have spring pins which can get very irritating. Using two bread-boards seemed a better option. As you can see, there are two regulator knobs. One is used to vary the frequency of the astable.  The one below it varies the DC input.
Timer Circuits

Before I begin, here’s the site where I got the astable and monostable circuits:

The circuits are pretty simple to construct on a general purpose PCB. Once you are done, you’ll have to connect these in parallel with the other sections to the DC supply. However, the astable’s frequency must be variable. You should have either 1Hz, 10Hz, 100Hz or 1KHz. To do this, I used 4 capacitors and a selector knob to switch between these values. Make sure that you do not fix the tactile switches directly to the PCB. Connect them to wires that are long enough. These switches will have to show up on the trainer kit’s base. The RC components for the two circuits are:
Astable:
R1 = 1KΩ
R2 = 680KΩ
C   = 1µF, 100nF, 10nF, 1nF
Here’s a photo of the astable circuit:

Monostable:
R1 = 100K
C   = 10µF
I made a small change or rather, an addition to the monostable circuit. I added a NOT gate to the output. This way I can get both positive and negative pulses for my sequential circuits. Here’s what the monostable looks like:

Output LED Circuit

Once you’re done with those two circuits, you’ll have to fix the output LEDs… these are basically 16 green LEDs, each connected to a 1KΩ resistor at the cathode. The resistors are given a common ground connection. The anode of the LEDs are connected to the outputs of the digital circuit (which you would construct on the trainer). The circuit for this section is:


You would also want to put those LEDs in holders before you solder them to the resistors. Here are some pics:

Input Power

I used an adapter which gives an output of 12V DC and a potentiometer to vary this voltage. You’ll usually require a voltage supply of 5V DC for most of your circuits. This supply is even given to the Vcc inputs of the timer circuits. A connection is also given to the bread-boards like this:

As seen later, there are alternate Vcc and ground connections in the kit.

Making The Base For The Trainer

Now that most of the circuitry is done, we’ll have to set up the base. This requires drilling and filing. So make sure you have a drilling machine, a flat file and a round file. Since I’m writing this article after finishing the trainer, I don’t have pics of the base once the required holes have been drilled and filed.Lets start with the holes required for the output LEDs. Use a drill bit thats large enough to make a hole that lets the LED holder fit through. You will have to make 16 of these holes. Right below each LED, you will need to drill holes for wires that connect to the anodes of the LEDs. These wires are connected to joints where you can make connections to the LEDs as outputs to your circuits. Once you are done with this section, you should have something like this:

Next we will have to make connections for the timer circuits. You’ll need a square hole for each tactile switch. I did this by drilling a tiny hole and then filing it to get the square hole. If you have tools to cut directly, then that’ll be great. Again, you’ll need holes for wires which then go to the joints just like the LEDs. I have also given connections to Vcc and ground. This was basically to measure Vcc values using a multimeter while changing its value. This is what you should have:

Now we need holes drilled for the potentiometer, the frequency selector and a square one for the switch. I got the square hole again by drilling followed by filing (which took a very long time). Two more holes need to be drilled for wires that go to the adapter and that finishes most of our work. This is what the base should look like:

To finish the top of the base, fix the two (or more if you want) bread-boards). You’ll need to drill two tiny holes for wires that give Vcc and ground connections to the bread-boards as I showed above. You’re base should now look like this:

You could now put labels for the various sections and make an small dock for the adapter. For this I used two left over spacers (we’ll require these for the lower part of the base) and a velcro strap:

Now we move on to the bottom section of the base. This can be done in about 10 minutes easily. You just need to drill a few holes and put some screws. You’ll have to put spacers at each corner and drill holes at the top of the base as well for screws to join with these spacers (It would be a good idea to drill these corner holes together in the beginning itself so that they are aligned properly). These screws Ive put in the middle hold the PCBs in place. These are optional. Here’s what the lower section of the base looks like:

On the left picture, you can see that I’ve fixed plastic legs for the base. These go right below the spacers. Now we’ll have to put the entire thing together. Fix the top of the base to the spacers and your trainer kit should be done. I’ll end with a pic of the trainer being used for a timer circuit:

The entire kit cost me around Rs. 500. Would have been cheaper if I used wood for the base since the switch boards itself were around Rs. 200. Hope you liked the trainer kit. Please post comments and suggestions or tell me if I’ve missed out on anything. Thanks for reading :-).

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14 Responses to Low Cost IC Trainer Kit

  1. krishna says:

    ur creativity is simply super……………..i am very glad to meet such a student like you

    • Ashwith says:

      Thanks :). There is a small problem with this however. The kit can’t take a large number of ICs. I’ll have to add a voltage regulator circuit when I find time.
      This kit is very basic. You could come up with some additions yourself.

  2. jayr says:

    hey! is this page still active?

  3. salman faris says:

    good job…..bdy…..

  4. salman faris says:

    bro, can u plz post the full circuit diagrams and pcb designes plz………………..

    • Ashwith says:

      I have given the links to the circuits in the tutorial. Here they are again:

      Astable: http://www.doctronics.co.uk/555.htm#reset
      Monostable: http://www.doctronics.co.uk/555.htm#monostable

      I did not design any PCB for this. I used a general purpose PCB which is available in electronics shops.

      • adithya says:

        I am Adithya and i really got impressed by your work sir .even I before a couple of months thought of constructing trainer kit .what I would like to suggest is to reduce its size and my best wishes to your up coming creative works

      • Ashwith says:

        I’m glad you liked it! Making the kit smaller is an excellent idea. I would recommend it. I don’t really plan on making another kit like this because I don’t really need one now. I can do any digital design I need on my FPGA board. You are free to use this design and improve upon it. You should note however that some of the circuits are not my own. I have provided links to the source.

  5. Rohit says:

    Hey wow! Superb….. hey would u like sell the kit….. If u, then i m gng to buy…..

    • Ashwith says:

      Nope I don’t plan on selling it. I wrote this tutorial so that others can make it themselves.

      My kit isn’t working as of now anyway. I’ve moved over to Verilog for my digital design work. The kit also requires things I didn’t know about before such as a voltage regulator circuit.

  6. mudassar manzoor says:

    if i use pure dc rather then monostable. what is difference between them.plz reply me?

    • Ashwith says:

      The monostable is used to get a single pulse. So if you want to send in a clock pulse one by one to test your sequential design, you can use it.

  7. bvsmanya says:

    Good project.students can build their own trainer.

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