Align holes in your project box without measuring – no special tools required.

In a previous post I described how to align holes without measuring. My original alignment tool was laser cut, but due to lockdown I’ve had to devise a simpler way to acheive the same accuracy using readily available materials – this time I use BluTac and an old milk carton.

Holes for the 3.5mm sockets are exactly in the right place.
Circuit board and project box
We can see where holes should be, but only from the inside.
Cut a piece out of an old plastic milk carton, to fit inside the box
Fold the plastic and add a thin layer of BluTac (other colours are available)
Press the plastic strip and BluTac onto the sockets to make an impression
Carefully remove the plastic strip
Position a bradawl in the centre of each hole and push through both layers of plastic
Holes punched through correctly
Re-attach the BluTac in EXACTLY the same impressions you made previously. Accuracy depends upon it.
Carefully insert the circuit board into the project box
Ensure the circuit board is in the correct postion, and press the strip onto outside of the box
Use the bradawl to mark the drill centres

Yes it’s just that simple. This method worked first time for me. If you are unsure, drill the -holes a bit smaller and file them out to be in the correct place. A 4 minute video of this process is here.

Check out my videos for accurately marking other types of hole without measuring –
USB-micro oval cut-out (as described in a previous post here)
Pin-hole (ideal for a recessed reset button)
Pinhole on the lid to show the recessed LED of Wemos D1-mini

Perfectly aligned holes without measuring

How to cut a hole to mate up with what’s inside your project box.

THE PROBLEM — You’ve made the electronics part of your project, and now need to cut a hole in your project box so you can plug in the USB cable. But how do you know where to cut? Unless the box is transparent, you can’t see exactly where the USB socket hole should be. There is a short (2:40) video of this post here.

Update: At the bottom of this post, there are links showing how to locate drill centres WITHOUT any tools.

Hole is in exactly the right place. and allows for plug housing
Micro USB plug fits neatly

The usual way is to measure the internal position of the USB socket when the PCB is fully in the box (not always possible) and transfer the measurements to the outside of the box. You have to be able measure and mark accurately.

PCB ready to fit into the project box.

This little tool provides a drilling and cutting guide on the outside of the box, when the USB socket is on the inside of the box (possibly hidden from view). No measuring is required.

Align the two strips

My design is quite simple. Overlay two strips and fix them together at one end – similar to tweezers. The strips staddle the wall of the project box, one strip inside the box, the other outside. The inner strip is fixed into the USB socket, and the outer strip has guide marks for the required opening.

Thin yellow inner strip is clamped in position.

The inner strip — should be reasonably thin so it can fit between the PCB and the box. I cut a 10mm wide strip off an old credit card, narrowed it at one end to make a tab that fits snugly into the USB socket, then bent the tab 90 degrees (warming helps but is not essential).

Line up the outer strip’s tab with the drill holes.

The outer strip — should be stiff transparent material. At one end, mark where the cut-lines and drill holes should be for the USB socket. Align the inner strip’s tab with the outer strip’s markings, then fasten them together at the other end. That’s it!

Fit tab into the USB socket

USAGE — To use the template, insert the tab into the USB socket and slide the circuit board and the inner strip into the box. Ensure the outer strip is flat to the outside of the box and use the cutting guides to mark the box. My original marks were the drill-centres for a couple of 6mm holes. Use a drill press for accuracy, and a small file to smooth and adjust the drilled holes to the final shape.

Slide the PCB and the tool into the project box.
Mark through the drill pilot holes

This technique will work on plastic or metal, and can be adapted for any shape of socket and hole. Draw the marking guide to accept the largest plug you may use.

View of how it looks on the inside.

CONCLUSION — Cutting holes in the right place is something I have always struggled with. I have to admit I was amazed when this worked first time!

Alternative view

Credit goes to Alan Bailey for helping implement this project from concept to completion in just a few hours. Below areYouTube links showing how it’s done, and how to locate holes WITHOUT any tools.

A Model Lighthouse

Designed and built at the Sheffield Hackspace using an arduino and bits and pieces of things that you might find lying around in your own home…

Here’s the setup:

An arduino (pro mini) for controlling the SG-90 servo motor
An ESP8266 for wifi access and neopixel control
A piece of gutter and downpipe for the main body
A plastic dome sourced from a solar powered garden lamp
An Aldi’s peanut butter jam jar lid (crucial)
Other bits and bobs scrounged from various unwanted poundland items

If you think this is cool wait until you see the boats!

A wi-fi and touch controlled NeoPixel ring using the Wemos D1 Mini ESP8266 module.

This project describes an easy way to control a strip or ring of WS2812 LEDs via a web page. It was originally based on the Arduino FastLED library.

Although the FastLed library code gives us a great example of how to control NeoPixel rings and strips, it doesn’t provide for user interaction. So it was decided to add the ability to control the device by wi-fi, and also have a touch switch for local control.

Materials required
A Wemos D1 Mini module was used as it consisted of a low-cost ESP8266 wifi chip and antenna, and it can be programmed by the familiar Arduino software. The Wemos module sits in a socket which is soldered to a matrix circuit board. This allows the module to be swapped out if needed, and also makes it easier to connect the touch-switch and neopixel wires.

A touch switch module was chosen rather than a discrete push-switch as it can be hidden behind the acrylic case and should also provide more reliable switching. The 100 x100 x 25mm square case was laser cut from 3mm acrylic, and was designed using the makercase on-line designer. This is the quickest software for making simple boxes. An extra 100mm square piece was cut for the front, with two circular cuts to accommodate the neopixel ring so it can lie flush with the front surface. Later, the touch-switch hole was cut so the sensor sits behind only one thickness of acrylic.

Laser cut acrylic case

The components fitted easily inside the box – it has plenty of room for a battery pack if you wanted to make it totally portable.

The touch switch sits in a rectangular cut-out.
Here is a view before the centre cover is glued on.

Software overview. The project uses websockets so that any web browsers connected can control (and be controlled) by the device. The touch-switch also controls the software and the settings are communicated to all connected browsers via websockets in real time.

User settings are stored in an object, derived from the ‘userDataClass’. This object stores settings for the brightness, colour, active pattern, demo pattern, provides functions for brightness gamma correction, etc.

The touch-switch code decides whether the switch received a tap or long press. A tap changes the pattern and a long press increases/decreases the brightness. Debouncing the switch was achieved by using a 32 bit integer and bit-shifting each switch reading into it. This method has both the advantage of being able to check for a steady switch state, and to discriminate between a short or long press. A future article will explain exactly how this is done.

Here’s a video of it working.

Making a kit knife

Since moving into the Portland Works in January 2015 I have had a desire to learn more about knife making. Obviously there is a long tradition of knife making in Sheffield generally, and more specifically at the Portland Works (https://www.sheffieldhackspace.org.uk/585) so it felt fitting to start exploring this new interest at the hackspace.

Fast forward 18 months and I’d still not made any progress but a few minutes spent in our neighbors workshop (http://stuartmitchellknives.com/) during one of the Portland Works open days inspired me further and I went home that day and ordered a piece of tool steel with the firm intention of getting moving. However life got in the way yet again and a temporary pause was once again placed on my project.

When I did finally think I had some quality time to spend on knife making I pulled out the piece of steel I had brought and looked at it. Something was nagging at me. Some advice I had been given was “Start small”. Great advice for any new endeavor of course, but more specifically I’d been advised to make a knife from a kit instead of a piece of steel. The reason being is that finishing a knife off, attaching and shaping the handles essentially, is quite a challenge in itself so the first time you do it it probably isn’t the best idea to attach them to a piece of steel you have spent hours working on and then mess it up!! Much better to learn your lessons on a blade you haven’t got so much time invested in.

I’m going to say right now that this is Part 1 of a 2 part blog, this detailing how to assemble the handle on a kit knife, the second part will be how to make the knife blade itself. Right. There, I’ve said it so I have committed to part 2 now. Anyway… On with the build.

The knife kit itself is pretty simple. You get a blade, two pieces of material for the handle (in my case olive wood), a couple of liners to go between the blade and the handle material (optional but can add strength and a nice visual contrast), two bolts for securing the handle to the blade and a metal tube for passing a lanyard through.

Once you have assembled all the parts you need for the build it’s time to get making! The first step is to drill the fixing holes for the bolts and the lanyard tube through the scales (handle material) and the liners (if using). These holes need to line up perfectly, and be at exactly 90 degrees, so I clamped the handle of the blade to both my wooden scale and the liner and then used the drill press to go through the existing hole in the blade handle (after measuring it of course). Once complete I attached the bolt through the hole I had just made to make sure that it couldn’t slip out of alignment as I drilled the next two holes, one for the second bolt and the other for the thong tube.

Before removing the bolts and clamps I marked the liner material around the edge of the blade, so I could cut it out on the bandsaw, making sure I also noted which side of the blade it belonged to. I then removed the bolts and clamp, removed the liner, then placed the bolts through the handle scale and blade again so I could mark up the wood for cutting. Once complete for one side I flipped the knife over and repeated the drilling / marking process again.

The next job was to roughly cut the handle shapes out. As I previously mentioned I used the bandsaw at the hackspace to do this but this could easily be done with any handsaw, or even files and wood rasps.

There are a number of different bolts / pins / fasteners that you can get to secure the scales onto the knife handle so this next step my not be necessary but I had to countersink the heads of my bolts into the handle so I used a larger drill bit (sized to the bolt head) to drill about halfway into the wood giving me a stepped hole. I actually hacked together a step drill bit to do this to give me a nice flat shelf at the base of the hole but just countersinking would work just fine.

At this stage the handle scales are almost ready to attach to the knife blade, however it will make life much easier to precisely finish the blade end of the scales first. Once attached to the knife it would be very difficult to get abrasives to the end of the scales without ruining the finish of the knife so this is best done now. To make sure the ends were symmetrical I attached them together using the bolts I had used earlier, and that will be used to eventually permanently attached the handle to the blade.  I used the belt sander in the hackspace to do the shaping, but again rasps, files and sandpaper would work fine.

Now its finally time to attach the scales to the knife. In addition to the bolts that connect the two halves of the scales a two-part epoxy is used to glue all the parts together. Due to the rather short working time of the epoxy, typically around five minutes, it is definitely best to dry fit all of the parts together to check for a good fit. Once you are happy everything will fit wrap the sharp part of the blade with masking tape, and then mix up the epoxy and attach the all parts together, ensuring that everything, including the bolts, gets a good coating of epoxy and then apply clamps (trying not to let the epoxy squeeze out get on the clamps or you’ll glue them to the knife as well!!). As I mentioned earlier the working time of the epoxy is approximately five minutes, but its advisable to leave the clamps on for at least 24 hours to ensure the epoxy is fully cured.

Once the epoxy is fully cured the clamps can be removed and the shaping of the handle can being. The first job is cut the bolts flush to the wood. You have to take care while doing this not to overheat the bolts as it can affect the strength of the epoxy, so I chose to cut these off with a hacksaw instead of grinding them off on the belt sander.

From there I used a wood rasp to remove the bulk of the material until I got close to the profile of the blade, then switched to files to get the wood closely profiled to the metal.

I then switched to the belt sander again to remove some of the width from the handle, rocking the blade left and right slightly to give it a curved profile for a nice feel in the hand. It is important to do this shaping over the metal platen on the belt sander as this will ensure that the metal bolts are ground away at the same rate as the soft wood on the handle.

To finish the handle I used small strips of sandpaper, starting at around 120 grit and then moving up to 400 grit, and pulled them around the handle until I had a nice smooth finish, paying close attention to the bolts making sure they were nicely polished.

The final step is then to add a finish to the handle, I chose boiled linseed oil which I applied with a cloth in several coats, rubbing off the excess between coats. The kit I purchased also included a leather sheath that I need to put together so I will include that in a blog post soon.

Make a hedgehog house for your garden

We’re getting toward hedgehogs’ hibernation season, so Sarah built a hedgehog house for her garden, and wrote up her process for others to follow. It’s a fun weekend project; if you make one, we’d love to hear about it. Of course, we have all the tools you need in the hackspace, for all members to use. Call in to one of our open sessions to take a look.


Use a hand saw to cut a 6” diameter pipe to min 30cm.  (Electric saws will melt, not cut the plastic.)  File the edge smooth.  This is the entrance tunnel that will prevent foxes/badgers etc fishing the hedgehogs out of the house.

Sarah's Hedgehog house 1

Balance a 30L storage box on the end of the pipe and draw around the end of the pipe with a marker pen.

Sarah's Hedgehog house 3Sarah's Hedgehog house 2

 

 

 

 

Use a dremel or similar on a slow setting  to cut out inside of the pen line.

Sarah's Hedgehog house 4

File smooth the inside and outside of the cut edge.   Use the marker pen to measure out 3cm points along both long sides, under the overhang.

Sarah's Hedgehog house 5

Drill ventilation holes through each pen mark on both sides.

Sarah's Hedgehog house 6Sarah's Hedgehog house 7

 

 

 

 

 

Unscrew the nut and remove the washers from the 90 bend pipe.  Place against the short end of the box, near the top edge and draw around the inside of the washer. Use a hole bit to drill out the same size hole as the pipe.  Put the washer on the pipe and nut.  Fasten the pipe to the box.

Sarah's Hedgehog house 8Sarah's Hedgehog house 9

 

 

 

 

 

Drill 6 drainage holes in the bottom of the box

Sarah's Hedgehog house 10

Push the large pipe into the big hole in the box.  Put the lid on.

Sarah's Hedgehog house 11

Locate the box in a quiet area of the garden, with the pipe pointing away from prevailing winds / the north / east.  Cover with leaves, but do not fill with anything.  Apparently, hedgehogs prefer to find their own bedding.  Make sure there are holes in your & your neighbours’ garden fence/hedge/wall/gate so they can get into your garden.  They will roam 1-2 kilometres a night looking for food so access is important.

One the box is installed, do not disturb.  Clean annually in early Oct with cleaner used for bird cages.

Sarah's Hedgehog house 12

Programming the ATtiny85 using an Arduino UNO

By Richard M Langner

This article describes how you can use an Arduino UNO to program a bare ATtiny85 micro-controller chip. I will show you how to program the ATtiny85 with the ‘Blink’ sketch. These are the steps –

  1. Connect the UNO to the ATtiny breadboard and connect the 10uF capacitor
  2. Configure the Arduino as an In-circuit Serial Programmer (ISP)
  3. Insert the ATtiny85 into the breadboard
  4. Configure the IDE for the ATtiny85
  5. Modify and upload the ‘blink’ sketch to the ATtiny85

1. Connect the UNO to the ATtiny85 breadboard and connect the 10uF capacitor
Connect the UNO to the breadboard as shown below. If you intended to keep the breadboard and UNO solely for programming, I recommend using an 8 pin socket for the ATtiny85 – this will ensure you insert the chip in the correct place each time on the breadboard.
Don’t insert the ATtiny85 in the socket yet – you must first configure the UNO to act as a programmer.

Pin connections:

  • ATtiny Pin 2 to Arduino Pin 13
  • ATtiny Pin 1 to Arduino Pin 12
  • ATtiny Pin 0 to Arduino Pin 11
  • ATtiny Reset Pin to Arduino Pin 10
  • ATtiny Pin 2 to 150Ω resistor, resistor to LED anode, LED cathode to GND (not shown here).
  • 10uF capacitor connects between GND (-) and RESET (+)

(Click on the images to get a clearer image.)

Uno as an ISP

2. Configure the Arduino as an In-circuit Serial Programmer (ISP)

Select the Arduino UNO board
setup-isp-1

and open the ISP sketch.
isp

Next you should upload the ISP example to the UNO board. Ensure you have selected the correct COM port.
download-blink

Congratulations! Your UNO is configured as a programmer.

You’re now ready to program the ATtiny85 with the ‘Blink’ sketch. You will need to connect an LED to display the blink. Connect a 150 Ohm resistor to the physical pin2 on the chip. The other end of the resistor should connect to the LED anode (its long leg), and the LED cathode connects to GND.

3. Insert the ATtiny85 into the breadboard

Remove the power by unplugging the USB cable. Taking care, insert the ATtiny chip into the breadboard socket the correct way around. Re-connect the USB cable.

4. Configure the IDE for the ATtiny85

Configure the IDE as follows –

  • Board  =  ATtiny85
  • Processor  =  ATtiny85
  • Clock speed  =  8MHz

2016-10-01_00037 2016-10-01_00038

Set the programmer ‘Arduino as ISP’
2016-10-01_00039

If the ATtiny85 is new, it will require the fuses to be set.  Among other things, fuses set the CPU speed. The fuses only need to be set once for each chip. To do this, select the ‘Burn bootloader’ option.

2016-10-01_00040

5. Modify and upload the ‘blink’ sketch to the ATtiny85

Open the example sketch ‘Blink’ and change the LED’s digital pin number to 3 on all the sketch lines (this is because the ATtiny85 does not have a pin13. Note that physical pin2 on the chip is digital pin3 on the ATtiny85). The code should look like this –

// the setup function runs once when you press reset or power the board
void setup() {
  // initialize digital pin 3 as an output.
  pinMode(3, OUTPUT);
}

// the loop function runs over and over again forever
void loop() {
  digitalWrite(3, HIGH);   // turn the LED on (HIGH is the voltage level)
  delay(1000);              // wait for a second
  digitalWrite(3, LOW);    // turn the LED off by making the voltage LOW
  delay(1000);              // wait for a second
}

Finally upload the ‘Blink’ sketch to the ATtiny85.
download-blink

That’s it! The blink program should now flash the LED.

The UNO is now set up as a programmer and so further ATtiny85 chips may be programmed by simply plugging them into the breadboard and uploading your code to them.

Richard Langner
With thanks to OJ for his help in defining the procedure.
This is my first post here, so please let me know if there is anything missing or incorrect.

Bookcase with clock stand

One of my own projects this time: a bookcase with an upright to hold a favourite clock. I didn’t want to drive nails into my (rented, plasterboard) walls and can always use extra shelf space, so I came up with this as a woodworking project. I’m a complete beginner at woodworking, so I learned a lot making this and had a lot of help from other hackspace members. It’s not perfect, but it does its job and I still have all my fingers so I’m calling it a success. At least, until I start work on version 2…

Want to learn some woodwork, or any of the other crafts and skills that our members get up to? Come along to your local hackspace!

A few recent snapshots

A few of the things we’ve been up to in the hackspace over the past week or two: Sewable arduinos (floras) and crochet, woodworking on the new lathe, silverwork on the jewellery bench, soldering up some electronics projects, painting the walls for our cellar expansion while planning the next builds, and lots of coding, writing and chatter.

Want to meet a friendly group of makers, whether to work on your own projects or as a beginner to learn new skills? Call in to one of our open sessions to see the workshop, say hi, and learn about how the group works.

At our latest Monday open session:

Lots going on at our latest open session: lasercutting shadowbox art, testing a pancake laser-engraving machine, making cosplay armour, and building a wireless arduino project. Got an idea? Make it with us! Come to one of our open sessions to see the workshop, chat, and join in!