11-8-2015 Update:

With OS X 10.11 El Capitan incorporating SIP (System Integrity Protection) it will break your previous install of PicKit2GUI. You will need to disable SIP before you can copy the needed files into the /bin/ directory to get PicKit2GUI to work again.

I found I also needed to install Java for OS X 2015-001 package first to get the JAVA runtime installed on OS X 10.11

Reboot your Mac into Recovery Mode by restarting your machine and holding down Command + R until you see the Apple logo. Then click Utilities > Terminal

In terminal window type the command: csrutil disable

Restart you Mac and SIP will be disabled. You are now able to re-copy over the pk2cmd and PK2DeviceFile.dat to the /bin/ directory.

Don’t forget to run: sudo chmod 777 /bin/PK2DeviceFile.dat

Recently I programmed 50 PIC16F684 chips to use ElectricDruid’s TAPLFO program. I have been asked by a few people how I burned the chips and with what. I decided the best thing to do was make a quick walk through.

Since I did all this on my Macbook Pro, this tutorial will be geared towards a Mac but the concept is the same with a PC.

Why did I need/want these chips?

There have been some great pedal DIY projects that use this chip to tap in a temp from a foot switch. Here is a small list of projects that use this chip and I am sure there are many more.

• David Rolo’s Twin Peaks Tap Tempo Harmonic Tremolo – This is the project that got me interested in making my own chips since the retail cost here in the US was a bit high per chip.
• David Rolo’s Liquid Mercury Tap Tempo Phaser – A great sounding and versatile phaser. It can be set to 2/4/6 stages and can get standard vintage phasing or out of this word sounds.
• MusicPCB Tap Tempo Tremolo
• UK-electronic Tap Tremolo

What I needed/what I had on hand?

PIC Chip – You will need a PIC16F684 You can pick them up at Mouser or try your luck with some China ones on eBay.

USB Programmer – There are so many programmers out there that it is impossible to cover them all. This is usually the biggest stumbling block when getting started. I went with the CanaKit UK1300 USB PIC Programmer (PicKit2 Clone) since it also meet my needs at work. I really like the fact that the sockets are on board and I do not need any accessories for it to program out of box.

Software – I really wanted to use MPLABX on my Mac but I had nothing but troubles trying to get it to recognize the CanaKit UK1300 so I went with using pk2cmd. When searching for command switches pk2cmd I came across a really nice Java GUI called PicKit2-Programmer-GUI that worked perfectly.

TAPLFO Program – ElectricDruid has this available on his website for private use only. If you like to use it commercially please contract Tom Wiltshire. Dpwnload the Assembled HEX code here.

My Programmer:

To write the TAPLFO program to the chip do the following:

Hook up your programmer VIA USB. You should have some kind of status light on your programmer to let you know it is powered up.

Insert your PIC (PIC16F684 in this case) – This step can be done before or after the software is launched. I am asking for you to do it before we launch so you can see if PicKit2GUI detects the chip properly.

Launch the PicKit2GUI

As you can see from the picture above the software detected that I have a PIC16F684 inserted (Auto-Detect: Found Part PIC16F684)

Load up the TAPLFO.hex file downloaded from Electric Druid into the PicKit2GUI software by pressing the “Choose .hex” button

I always erase my PIC before any programing. I think its just a “best practice” and is most likely not necessary.

Erase:

Write:

Now lets write the HEX file to the PIC16F684. Press the “Write Hex” button.

Test Hex:

Another good practice is to test the HEX on the PIC to verify a working chip. Press the “Test HEX” button.

Now were are done. Just remove the PIC16F684 and place another in its place if you want to program more chips. There is no need to shut down the software or power off the programmer when changing the chips.

Now you can make some snazzy labels for your chips and get using them in your personal DIY projects.

Sticker Sizes: 16.34mm X 5mm 300DPI worked perfect for me. Print them on a full sheet of sticker paper and just cut them out as needed.

Here is a shot of some of my finished chips.

Edit: This is a work in progress and I wanted to put something up to get me started. A lot have asked me how I paint my enclosures after I do a reverse etch. I will attempt to explain my evolving process (I say evolving since its changing over time with trial and error).

Whats needed:

• Etched enclosure (Use this tutorial if you need to know how I do reverse etches)
• 1000 or 1500 grit wet sand paper.
• Small square item to use as a sanding block. I use an iPhone/iPad charger… really, I do, not kidding here. Do not use the charger for charging any iDevice after using it as a sanding block.

I first paint the enclosure with a nice even coat of rattle can paint. As of right now I love using the Rust-oleum STOPS RUST Metallic products. It dries even and the darker metallic paints help the reverse etch to pop out visually.

I bake the enclosure in a over at 150 degrees for 15 minutes then let it cool. If done properly and you take your time you can get good results with 1 coat. Remember, the more coats you put on the thicker the paint becomes and can give you problems when wet sanding. You can literally paint back all the surface area that you etched away and and your etch will be ruined. Some times I put one nice coat on the surface of the enclosure where the etch is located and several coats on the sides of the enclosure.

One painted it will look something like this:

Taking your mini sanding block (iPad charger in my case) wrap a strip of 1000 or 1500 grit sand paper.

I found that the iPad charger worked well since it is made from hard plastic and retain a flat surface unlink rubber sanding blocks. Laugh all you want but it works.. lol

I do this near my kitchen sink so I can constantly wet the enclosure & sand paper and wash off the enclosure. I then wet the surface of the enclosure and wet the sanding block and begin lightly sanding the raised areas of the etch. Soon you will start seeing aluminum. Do NOT concentrate on one are to long since it may sand away your raised area completely.

NOTE: You may want to start with 1500 grit sand paper so the chances of sanding away an etched area is a bit slimmer but you will find that 1000 grit speeds up the sanding process. Its up to you.

This is not the best etch but it will work for this tutorials purposes…for now.

Take your time and try to stay away from all edges since the paint is a lot thinner over the edges and will sand away with little effort.

With a little patience and time you will have something like this.

You will see some areas of the paint that dulled a bit do to the sand paper rubbing against it. This freaked me out the first time and I thought I ruined it but, it all disappears when you place a coat of clear on the enclosure.

Make sure you wash your enclosure good and let it dry for 20-30 minutes before spraying your first coat of clear on.

Finished pedal:

I hope this helps some. As always you can contact me here by leaving comments or look for me (selfdestroyer) over at Madbean’s Forums.