Friday, August 24, 2018

Workbench in the garage

I've been meaning for a while to set up a permanent workspace for doing electronics and finally cleared a corner of the garage.

Once cleared I of course needed a workbench and whenever I searched on line this steel bench kept coming up. Listed on the UK eBay for about £50 which to me seemed like an OK price to pay for a bench with main surface size of 120cm x 59cm and with a drawer the full length of the bench.



I asked on Twitter what it was like and a few people replied that the metal is quite light but it's sturdy once built.

I got one and for £50 I think it's definitely worth the price.

The metal frame is not the strongest or thickest metal I've seen and without the wood tops being in place it does flex. I expected to have to add braces at the side and back but in the end they are not needed as once the work surface and other wooden pieces are added it gets nice and rigid.
One thing to be aware of is the wood is MDF and so has limited strength in itself.
The lower shelf on mine is flexing already due to the boxes I have on it.  I note this in the video below and also my plan to add some wooden battens to support the lower shelf.
The lower shelf and the work surface are not screwed down and are held in by the frame so it will be easy enough to lift out the self add the battens and put the the shelf back on.

The draw was also pointed out to be quit flimsy and I agree. It's not robust but it works and for tool and storage for light parts it will do the job.  Again the base on the drawer is MDF.

The back pegboard on mine is slightly bowing out.  Not sure if I've done something wrong or if it's the kit.  The top shelf is OK.  Again I'm not expecting it to take much weight but as a place for odd small bits it will work well. It's also high enough above the main work surface that it should be ideal for adding additional lighting in the future.  Maybe some RGB LED strips 

Finally, the instructions are really poor.  The kit I received wasn't missing any parts but let's say with my flat pack skills it took me a fair while to get it all together. 
The one tip I'd give is watch the number of holes in the metal parts to figure out which way is up.

So, overall I'm very happy with the bench. I've used it a fair bit since getting it and I like the size.  Much smaller and it would be a challenge to have equipment out and have a decent sized work surface.  (There is a smaller sized version that's 81cm x 41cm and from searching eBay there are also versions without the back and top shelf.

Finally, here's a video of the bench so you can see what it's really like.



Onward and upwards with the making. 

Tuesday, August 21, 2018

Shakey Shakey - a game using title switches

For the most recent Egham Raspberry Jam @EghamJam we did two workshops.
One was NoPi Blinky, making LEDs blink without any programming. More to come on this as during the workshop we found a few typos.

The other was Shakey Shakey.

For the workshops my goal is to do something slightly different that not only teaches the attendees something new from either a programming or electronics standpoint but also shows them creative options.

Shakey Shakey was based around really simple tilt switches.  They're basically a small tube with a contact inside that moves as you tilt the tube.  Really simple and really cheap. On eBay UK they're about £1.50 for 20. So, ideal when you need a bunch for the Jam
Tilt Switch

The only other things needed then were some female-female jumper wires and some 2 core wire.
I cut the female-female wires in 2 giving me a pair of wires that had the female connectors on one end and bare wire the other.  Cut the 2 core wire into about 150cm lengths and used them to connect the switch to the other wires giving a nice long wire for the kids to shake without (hopefully) unplugging the wires or pulling on the Raspberry Pi.

With the hardware sorted I them did the worksheet which is available to download from GitHub along with other Jam worksheets.

Shakey Shakey worksheet
The worksheet goes through:

  • Connecting a tilt switch
  • Python code to read the switch and display how many times it connects
  • Adding a pause to deal with debouncing
  • Adding a second tilt switch
  • Updating the code so the switches have to be activated alternatively
  • Final update of the code to add a timeline making it into a game

We had a full workshop and the kids who took parts seemed to really enjoy the coding and then playing the new game they created.

At the end I challenged the participants to come back to the next Egham Raspberry Jam (21st October 2018) with their own program that uses the same tilt switch controllers.  The worksheet at the end gives some suggestions.  Here's looking forward to the 21st of October to see what fantastic creative ideas the kids come up with.





Tuesday, June 19, 2018

Cat or Dino- Scratch 2.0 game



I saw a tweet from the @Raspberry_Pi Foundation about a game called Knifey Spoony by @Jonic one of their senior web developers did using pico-8.





The idea of the game is to select if the image is a spoon or a knife as quickly as you can with a timer running getting faster and faster the higher your score, so the pressure is on.

I thought this could be done with Scratch, so I fired up Scratch 2.0 and had a go.

Here is the result.  It uses only built in graphics making it easy for anyone to replicate and extend.
It is done with Scratch 2.0 but there is nothing special so it should work with Scratch 1.4 on the Raspberry Pi as well.

https://scratch.mit.edu/projects/229582133