Posts with «vintage» label
Julian Hespenheide is an interaction designer based in Germany who submitted to Arduino blogpost a writing machine called émile. It’s an interactive installation created in collaboration with Irena Kukric, David Beermann, Jasna Dimitrovskais and using Baudot code - a binary 5-bit code, predecessor of ASCII and EBCDID – intended for telecommunication and electronic devices, representing the entire alphabet.
It runs on Arduino Uno and translates the bauds (/?b??d/, unit symbol Bd) into moving objects that are being sent over physical tracks in order to illustrate a simple computational process of 5-bit binary information transmission:
The machine was built in six days with four people. In our group we came to the conclusion, that not every process in a computer is really transparent and it already starts when you type a simple letter on a keyboard. To unwrap this “black box” of data transmission, we set our goal to build a small writing machine where you can literally see bits rolling around. After some research we got back to the beginnings of Telefax machines and data transmission using Baudot-code. We then quickly designed punchcards and mapped them to a slightly altered baudot code table and cut them with a laser cutter from 5mm plywood.
Whenever a marble hits a switch, a short timer goes off and waits for input on the other switches. If no other marbles are hitting those switches, we finally translate the switches that have been hit into the corresponding letter.
Take a look at the machine in action:
Several years ago, Chris Gregg, a Tufts University lecturer and computer engineer, received a letter from his friend Erica. This wouldn’t be so unusual, except that it was typed on an actual typewriter, not a printer. Gregg is a fan of vintage typewriters, but, as with myself, makes many mistakes, […]
In the following 10-minute video, the Currah team is showing us all the details of Wood Lizzie, a project experimenting with Arduino Mega and Wi-Fi Shield, a very flexible steering system and the virtually unlimited control range afforded by WiFi and Internet Protocol:
The original plan was to construct one of the two-wheeled robots very popular with hobbyists but it was eventually decided that the resulting vehicle would be of very limited application and capable only of traversing smooth surfaces. However, note that the current design can be viewed as the drive of a two-wheeled robot coupled with a trailer by means of a 360 degree pivot. A slip ring capsule within the pivot enables the heavy battery and bulky control system to be separated from the drive and located on the trailer thereby distributing weight evenly between the four wheels.
DIY soap-carts were pretty common among kids in the first part of the 20th century and built from old pram wheels, scrap wood and, typically, soap boxes. They could provide a lot of fun for the family at very low cost and in recent years there’s a new interest in them especially to those appreciating their vintage look!
It’s no secret that I enjoy kit reviews – it’s always interesting to see how well a kit goes together, along with the quality of parts, documentation and so on. But what about kits from the past? And not 2003. Recently a very rare opportunity to purchase a sealed Sinclair Radionics Cambridge calculator kit appeared on ebay – so it was ordered rapidly and duly delivered to the office. And thus the subject of this review.
You may be familiar with the Sinclair name – Sir Clive Sinclair introduced many innovative and interesting products to the UK and world markets in his own style. Some were a raging success, such as the ZX-series home computers – and some were not. However in 1973 Sinclair introduced a range of calculators, starting with the “Cambridge”. It’s a simple four-function calculator with an LED numeric display and a somewhat dodgy reputation.
The design evolved rapidly and at the Mark III stage it was sold assembled and as a kit. At the time handheld calculators were quite expensive, so the opportunity to save money and get one in kit form would have been quite appealing to the enthusiast – in January 1974 the kit retailed in the UK for 24.95 (+ VAT):
Putting the Cambridge together required a balance of healthy paranoia, patience and woodworker mentality (measure twice – cut once). There wouldn’t be any second chances, or quick runs down to Altronics for a replacement part (well … there was one) so care needed to be taken. If you’re curious about the details, I’ve uploaded 82 full-resolution images from the build, including both instruction manuals and schematic onto flickr. Now to get started.
The kit arrives in a neat, retail-orientated package:
… with the components on one side of the foam:
… and the other side held he assembly guide (underneath which was a very short length of solder and the carrying case):
At this point I was starting to have doubts, and thought it would be better off in storage. But what fun would that be? So out with the knife and the shrink-wrap was gone, revealing the smell of 1974 electronics. Next to whip out the instructions and get started:
They are incredibly detailed, and allow for two variations of enclosure and also offer tips on good construction – as well as the schematic, BOM and so on. Like any kit it’s wise to take stock of the components, which gave us the PCB:
… the passives, diodes and transistor – and some solder wick:
At this point it turned out the all but one of the resistors were anywhere near the specified values in the instructions, and I wasn’t going to trust those electrolytic capacitors after 39 years. The replacement parts were in stock – including the original 1n914 diode that was missing from the kit. Thanks Clive. There was also a coil of unknown value:
… and the ICs, which included the brains of the operation – a General Instrument Microelectronics CZL-550:
… and an ITT 7105N:
… a bag of battery clips, buttons and adhesive-backed foam (which deteriorated nicely):
At this point it was time to fire up the Hakko and start soldering, not before giving the PCB a good hit with the Servisol cleaner spray. I was worried about the tracks lifting while soldering due to heat and old-age, however the PCB held up quite well. The first step is to solder in the clips that hold (just) four AAA cells:
… then the resistors and diodes:
… followed by the transistor, ITT IC, ceramic capacitor and coil:
Uh-oh – that ceramic went in the wrong hole. One leg was soldered where the coil was to sit. Without wanting to damage the PCB, de-soldering it was a slow, slow process. Then of course I didn’t have a ) 3.3nF in stock, so a quick spin to Altronics solved that problem (I bought 50) – one of which finally went in:
The transistor was also a bit of a puzzle, I hadn’t seen that enclosure type and the manual wasn’t much help, so the semiconductor analyser tester solved that problem:
The next step was to fit the display, which is wedged in the large gap at the top of the PCB. The tracks on the PCB are supposed to meet the display, however time had affected the tracks on the display module, so I soldered small wire links across the gaps:
Following the display were the two (new) electrolytics:
And now to the main IC. There wasn’t any second chances with this, and after some very gently pin-bending it dropped in nicely:
After a short break it was time to assemble the keypad, which went smoothly. After cleaning all the foam dust off the buttons, they dropped in to their frame which in turn dropped into the enclosure, followed by the keypad layers:
You can also see in the display window and shroud have been fitted. From here the PCB is inserted:
… and a sticker from years gone by, as well as the metal clip over the bottom of the power switch. At this point a quick test with four AAA cells showed signs of life on the display, so the rear enclosure could be fitted:
Now for the battery and final cover, and it’s ready to go!
The digits are quite sharp, but very small – and set back from the window. This makes photography quite difficult. At the time if your calculator didn’t work, you could send it off to Sinclair and they’d repair or possibly replace it for you:
Using the Cambridge
Well it works, so you have a calculator which is genuinely useful. However the Cambridge has a few quirks, which are attributed to the basic functions of the main IC. For example, when entering numbers the screen is filled with leading zeros until you select a function, however by using the manual you can complete complex work including square roots, percentages, loan repayments and much more.
Furthermore the Cambridge is quite the silent achiever, you can work with numbers as small as 1x10E-20 and up to 9.9999999E79. You simply enter the numbers in decimal form (e.g. 0.000000000123) … even though the display won’t show all the digits, they’re being stored in a register. To then extract the result, you continually multiply or divide by ten (making note of how many times you do that) until the digits appear on the screen. It sounds nuts today – but in 1974 it would have been a cheap way of avoiding a more expensive calculator. In the following video you can see th Cambridge in action, plus the results of dividing by zero:
More about Sinclair
The following video is a BBC dramatisation of the rise of the home computer in the UK market, and the competition between Sir Clive Sinclair (Sinclair) and Adam Curry (Acorn Computers) – which is quite entertaining:
From a 1974 perspective, that would have been a great kit to make, with some love and care it would have been successful. By today’s standards it was quite average – however you can’t really judge it from a 2013 perspective. Nevertheless, kudos to Sir Clive Sinclair for his efforts in knocking out a useful product as a kit. If you’re a collector, and see a sealed unit on ebay or elsewhere, give it a whirl. Just take your time, “think before doing”, and replace as many of the components as possible. I’ve put all the images in full resolution up on flickr, so you can follow along in more detail.
And while you’re here – are you interested in Arduino? Check out my new book “Arduino Workshop” from No Starch Press.
In the meanwhile have fun and keep checking into tronixstuff.com. Why not follow things on twitter, Google+, subscribe for email updates or RSS using the links on the right-hand column? And join our friendly Google Group – dedicated to the projects and related items on this website. Sign up – it’s free, helpful to each other – and we can all learn something.
A project by Chris Bell, Liangjie Xia, and Mike Kelberman called Rotobooth is a hacked rotary phone that takes your picture as you’re calling your own cell phone, then sends a link of the photos to you by SMS.
The rotary phone was hacked using Arduino, the photos were collected on a Flickr page, and finally the SMS notification is sent using Twilio. The exterior design is clean (dig the orange phone!) and recently took 3rd place at Twilio’s Photohack Day 2.
- Antique Crank Phone Modded as a Music Player
- Use a Rotary Phone as a Cell Phone Handset
- Cordless Candlestick