Who wouldn’t want to build a computer out of relays? We do, but we’ve got too many projects on our plate already. It looks like [rory] has his priorities in order because his build is one of the most amazing we’ve ever seen.

We’ve seen [Harry Porter]‘s amazing relay computer and we’re familiar with [Konrad Zuse]‘s WWII era endeavours. Relay computers aren’t exactly uncommon, but [rory] built the TIM-8, that may be the smallest 8-bit relay computer ever. The total relay count in the TIM-8 is 152 compared to [Harry Porter]‘s 415 relays. This isn’t a fair comparison because [Harry]‘s uses 4-pole relays, while the TIM-8 uses 1-pole relays, making the [rory]‘s project 8 times smaller than [Harry]‘s.

There are a couple of neat features that makes the TIM-8 really exceptional. Programs for the TIM-8 are written in a text editor on [rory]‘s desktop,  then compiled and printed onto receipt paper. The TIM-8 has a few phototransistors to read the bands of white and black printed on the paper. [rory] has come a long way from a three bit adder made with relays and light bulbs.

Check out a ton of videos after the break. There’s a few demos of programs running off of receipt tape, calculating the Fibonacci sequence, and playing ‘Mary Had a Little Lamb’ on the relay sound card. Thanks to [J. Peterson] for sending this one in.

[Quinn Dunki] keeps rolling with her 6502 based computer build. This time around she’s added some memory to store the programs, but needed a way to get that code into the device. Above is her solution, a bank of hex switches used to program the 8-bit command and 16-bit address for each line of machine code.

This is a continuation of her Veronica project. The last time we saw it she had hardwired the logic levels for the data bus, but that’s no fun since nothing can actually be computed. [Quinn] picked up an SRAM chip which will store the program. It’s compatible with the 6502′s memory bus, but needs a bit of extra circuitry for her to be able to hand program it with this switch bank. She used some tri-state buffers to switch between connections to the processor, and to the hex switches. This way, she disconnects the RAM from the processor using the buffers, uses the switches and push button to clock in the program, then patches the RAM back into the computer.

Seeing this process in the video after the break certainly gives you an appreciation for what an improvement the punch-card system was over this technique. Still, seeing this is a delight that we’d like to try!

If you want people to really be impressed by your projects it’s often better not to have a fully finished look. In this case, we think hooking the stripboard version of FIGnition up to your TV will raise a lot more eyebrows than the PCB version will.

[Julian] put together a guide to building the computer on strip board. He’s using his own Java application for laying out circuits on this versatile prototyping substrate. This tool is worth a look as it may simplify those point-to-point solder prototypes you’ve been agonizing over. You’ll have to do some poking around on his site to gather all of the knowledge necessary to complete the build. Most of the components are easy to source, but unless you have them on hand, you’ll need put in a parts order for the crystal, the ATmega168, the SRAM chip, and the flash memory chip.

For those not familiar, FIGnition is an 8-bit computer with composite TV-out for a display and rudimentary input from the eight momentary push buttons.

Wood and electronics don’t generally mix nowadays, but if you yearn back to a time when radios and the like had a nice wooden finish, this wooden computer case may be for you. Combine that with a Wooden keyboard enclosure, and maybe even a LCD monitor stand and you’ll have a setup that should fit in with any wood-themed decor!

The wooden computer case is actually more of a cover in that it uses most of the stock case to house all of the components.  It would definitely be a pain, and possibly a fire-hazard, to make a back mounting plate for all the components out of wood. To go along with this, the LCD monitor stand was engineered for a 21″ monitor when the owner of it wasn’t satisfied with the stability of the stock stand.  In the end, he ended up building something quite sturdy and nice looking to replace it.

The highlight for many for the keyboard would be that it was made, in part at least, out of a desire for a Commodore-64 keyboard.  It appears to function well andlooks great, so be sure to check out the other pictures after the break!

[M. Eric Carr] came up with an interesting build for the 555 contest earlier this year, and we’re pretty sure that it would have kicked the winner of the complex category off the throne if it were completed. Although it’s a few months late, we’re happy to feature at least part of his 555-based computer on Hack A Day.

[M. Eric Carr] started off implementing Boolean logic with a 555. After building a universal gate, he moved onto putting one bit of memory in a single 555. This design uses the 555 as a latch and is one of the craziest off-spec uses of a 555. While fitting 24 bits of memory on 5 large bread boards may seem like a waste, it’s a far cry from the square feet or acres of other computer builds we’ve seen.

From the post on the 555-based memory, [M. Eric Carr] says a completed design of his computer could be up and working this summer. It’s already August, so we’re hoping he’s still working on his design. Check out the video of the memory below.

If you think that your water cooled rig is pretty sweet, check out this creation by Dutch PC enthusiast [Peter Brands] (Google Translation).

With his computer tweaked as far as he could imagine, he decided to spruce up his office a bit. In the process, he ended up tweaking his computer just a little bit more. After seeing a build put together by another computer enthusiast, he set off to construct a desk in which he could show off his computer. He spent some time drawing up plans with Google Sketchup and with the help of a friendly neighbor, started construction of his desk/PC case.

The desk is constructed from 3mm thick aluminum, and houses most of his computer’s components under a thick piece of glass. The only portion of the computer that is not enclosed in the desk is the 9-fan radiator he used for his water cooling setup. That part resides in his crawl space, which he connects to his PC via a pair of large water hoses he punched through his tile floor. If you are interested, you can see all 800+ pictures of the build here.

Simply awesome!

[Thanks duchie]

[Mark Fickett] finished his own interesting take on a bicycle computer. These wristwatch-sized devices normally mount to the handlebars and give feedback for current speed, trip distance, and many have options like cadence and heart rate. [Mark's] has fewer features but it’s clean, simple, and does more than you’d think.

He used some denim to house the electronics which you can see mounted inside the frame of the bike. He’s chosen to use Lilypad components which are Arduino bits meant to be sewn into textiles. We’ve seen a Morse Code keyer using these components and this project is along the same lines. It reads wheel revolutions from a magnetic sensor mounted on the front fork. It has no LCD readout, but when you want to know how far you’ve traveled just press one button and the computer reads it back to in Morse Code played on a tiny piezo buzzer. This package hides one more nice option. Once you arrive home the trip data can be dumped onto a computer for easy graphing. Check out the video after the break to see these features in action.

[via Dangerous Prototypes]

[Ed Zarick] built a module to control his vehicle which he calls the Jeeputer. The name’s a mash-up of Jeep and Computer; the device itself is a combination of Arduino, character LCD, and a collection of shift registers and relays for interfacing. Watch the video after the break to see what this can do. We were surprised in the beginning when he says that all he has left to do is remove the steering wheel lock and he’ll be able to drive using the interface, but we think he means type in a code to unlock the ignition, not remote control for his car. He then goes on to demonstrate garage door control, power cycling for CB radio, GPS, 110V power inverter, vehicle light control, and much more. This must be the most feature packed car computer we’ve seen so far.

This is Zusie, a computer built out of electromechanical relays. [Fredrik Andersson] picked up a lot of about 100 telephone exchange circuit boards, each with about 16 relays on them. After getting to know a heat gun really well he ended up with 1500 working relays with which to play. The machine runs slowly, it iss noisy, but it definitely works. After the break you can see it running and assembly code program that he wrote.

The instruction set is based on boards running microcode. These store the operational commands for each instruction the processor has available to it and they run in parallel with the rest of the operations.

We’re always surprised to see that these home-built processors work. Mostly because of the complexity involved in assembling them. How hard is it to find a shorting connection or a malfunctioning relay? Those problems aren’t limited to this application either, what do you do if a transistor-logic CPU has a malfunctioning chip?

[Thanks Daniel]

We’re rather surprised at how popular it has become to build your own motorcycle computer. [Mario Mauerer] tipped us off about his shiny motorcycle computer (translated) for his Yamaha XTZ 750. It uses an ATmega644 microcontroller to pull a variety of data together and display it on this white LED backlit display. He connected a flow meter to the fuel line to monitor gas consumption. Oil temperature is captured by inserting a brass tube (containing the sensor) through a hole in the oil cap and soldering it in place. Water temperature is gathered by measuring the external temperature of one of the cooling lines. [Mario] uses a rotary encode with a click function as the control interface device, and a battery backed real time clock keeps time.

A quick look at the PCBs tells the tale of good circuit design. But we do wonder about catching the reflection of the sun in that shiny bezel.

Take a few minutes out of your day, grab your scissors, and learn how a simple processor works. [Saito Yutaka] put together an exercise to teach processor operations with paper. After downloading the PDF you can cut out the Address and Data pointer as well as two-bit data tokens for each. The processor has three instruction sets; Increment register by one, Jump if not over flow, and Halt wait for reset.

Once you’ve got your cutouts you can follow along as the program is executed. The INC operation is run, with the JNO used to loop the program. Once the register has reached an overflow the overflow counter halts the program.

One word of warning, we think there’s a typo in one of the captions.  Once the program starts running and gets to address 01(2) the caption still reads 00(2) for both address and data. As long as you compare the values in the picture along the way you should have no problem getting through execution. which has now been fixed.

The year is 1988, where a Russian engineer [Vladimir Demin] has combined a Bayan, or button accordion, with several (we lost count at about 96) solenoids. If that alone doesn’t blow your mind the computer, also hand built by [Vladimir], controls the whole process leaving the operator to only work the bellows. Putting truth to the fact in Soviet Russia, accordion plays you. We wish we could find some more information about the instrument, but curse our inability to read Russian. Alas check after the break for a shorter version of the video in the link above.

Related: Electronic accordion doesn’t compare.

[Ben's] added some nice goodies to his Volvo in the form of an in-dash computer. The system monitors two pressure sensors for boost and vacuum, as well as reading RPM, O2, and exhaust directly. All of this is tied into the touch interface running on an eeePC 900A. But our favorite feature is that the system requires you to enter a PIN to start the ignition. The forum post linked above is short on details so we asked [Ben] if he could tell us more. Join us after the break for a demonstration video as well as [Ben's] rundown on the system.

Ben writes:

Hi, great, glad you like it. The EEE 900A has a 2GB ram upgrade and a 16GB SSD upgrade, running windows 7. I modified the computer so it could fit directly behind the screen, which involved relocating the USB ports, and also using a HP webcam from a broken laptop as a back up camera.

The black box has three circuit boards. I’ll send you some pictures of the most current version later. The first board is for power, It has a 3.3v and 5v regulators to provide the two voltage rails, and the three relays. One relay controls the power supply to the netbook, the second controls the car’s actual starter, and the third controls the auxiliary power and lighting system.

The second board uses two freescale semiconductor pressure sensors, one to read boost and the other to read vacuum. It also has a secondary microcontroller (A PIC18F2550) to read a direct RPM input as well as a wideband o2 sensor in the exhaust. This uC is running in i2c slave mode.

The final board in the back is a PIC18F4550, which has direct control over the relays, the secondary controller, and also directly reads the two pressure sensors. Both controllers run software written in PICBASIC.

Now the part that I like about the interface box, is in order to talk to the computer, it uses only the PIC18F4550′s USB port. one usb connection is all that the computer talks to the car with.

The software running on the netbook is an application that provides a front end to the control box, A PIN is required to be entered, and once the PIN is correct, you are then able to start the car via the
button on the screen. The normal key method of starting no longer works. For security, The interface ONLY sends the PIN number to the control box, the control box has a PIN number saved and encrypted on the PIC’s internal eeprom. The entire application was written in VC++, .net, and provide me with accurate boost, vacuum, RPM, and AFR on screen. Touching a gauge on the screen enlarges it, and minimizes the other two gauges for enhance readability.

It’s all cleanly installed in my 1998 S70 T5, which was an automatic from the factory and that I swapped to manual in January this year. To power the entire system on, you only need to press the unlock button on the keyfob. by time you get to the car, the computer is running, and the control box is connected to my software and waiting. Locking the doors via key fob (using the key on the door also works just as well) tells the contol box to use a transistor to electrical press the EEE’s power button and put it into sleep mode. Once the EEE is off, it cuts power to the EEE, and then both controllers go into sleep mode, drawing minimal current. I’ve left the car for a couple weeks with the entire thing hooked up, got home, and started it right up and drove away. I designed the entire system like any company would, to ensure reliability. There are safety measures that only I know about, that allow me to re-enable the standard key ignition in case of an emergency.

[Muth] added an auxiliary display to his motorcycle instrument panel. He started out prototyping with a PIC 16F877A which he used to access information through the ECM diagnostic connection. Once he had that working he found this tiny display which fits perfectly between the speedometer and tachometer. There’s a short demo after the break where you can see a past-30-minute history of the Adaptive Fuel Value and the engine temperature as well as a secondary information screen.

This is another nice addition to our collection of vehicle displays, scooter controllers, gear indicators, and motorcycle computers.

This computer can be mounted in any standard light bulb socket. It uses a pico projector combined with a camera to generate a touch display wherever you shine it. The photo above and the video after the break show the bulb in a motorized lamp arm but that’s just smoke and mirrors, the bulb itself is the core concept. We think there’s real potential for home-built versions. We’ve seen touch displays similar to this that mount on the side of a laptop, but why have the computer around at all? Ditch the USB connection for wireless and have it connect to your home server for processing power. It becomes a perfect solution for places that aren’t traditionally computer friendly. For instance, that kitchen computer you don’t want to touch with dough-encrusted hands becomes washable when the display is projected on a cutting board.

[Thanks Ryan]