{Devices} – Page 2

‘relaxation’ project – ‘building’ an autonomous maze solving car

Lately my ‘relaxation’ project has been dabbling in ‘building’ an autonomous maze solving car. Sounds grand, but in reality just using an off the shelf remote control Jeep and the RoboRacing bootstrap shield kit, both from the Xinchejian Hackerspace.

The Jeep has been stripped and an Arduino and the motor controller installed and tested.

The Arduino software has progressed to create an extensive framework manage:

task prioritisation
sensor data
collision and obstacle avoidance
selection from several maze solving algorithms
two simple maze algorithms trialled in simulator
additional logic to cater non-standard mazes and loops
basic motor control on/off and PWM motor control completed.

For more relaxation, a maze solving simulator has also been developed using Processing. It shares some of the Arduino program and data structure.

The Big “to do’s” are deciding on approach to sensors – type(s), positions, number and the collision and obstacle avoidance, guidance, position tracking, and all the other code I am sure to have forgotten or just think is already working. So tomorrow I am off for some more ‘relaxation’ at the monthly Xinchejian robot race to check out the track and sensors used.

So now I’ve gone public on this, pride is at stake, so I’ll have to give updates of my future progress, or I’m sure my competitors at Xinchejian will only be to happy to report on my lack of progress 🙂

OCN set top box menu language, PVR and more English content.

To change the menu language from Chinese to English and other languages, and back again.

First up, please read this post on the remote control English button names. It also has a brief description on using the PVR (recording) functions.

To navigate the menu system, read the on screen prompts, they do provide instructions on getting to the favourite menus and other sub windows panels.

To change from current language to English:

Turn on TV and the OCN STB.
Make sure you are viewing an OCN cable channel on the TV.
Press the following buttons on the remote and you should then see a screen similar to those below.
Press arrows keys until the yellow menu highlight is on the 5th menu on the left (second from the bottom).
Press OK or Right to select the inner menu.
Press up or down arrows keys until the yellow menu highlight is on the menu second from the bottom left corner.

Press OK or right to select the User menu, then Enter password 1234.

Press Down arrow to select User parameters, then press OK or right to enter the sub-menu.

Press down arrow to select 4th menu item, then press Left or Right arrows repeatedly, until the desired language appears.
Press Down to get to the OK, then press OK, then Guide, Exit, and finally Return.

To switch from English back to Chinese, the process is the same, except of course choosing the other language.

I have only tried this with the larger model that has the PVR functionality. The smaller STB & remote should work the same, and hopefully there is enough help here to get you going on that model.

The additional English content is mostly education or language, but there are a LOT of channels & “radio” stations, you may well find some interesting things that suit your needs, I’ve only had a quick browse!

I can confirm that the EPG is lacking a lot of detail. It really only lists the timeslot and type of show, there is no episode or movie information. For example you might see when a movie is playing, but it will not say what the movie is, and then a large portion of the EPG on the two English channels is still in Chinese. I guess the VOD (Video On Demand) button will work if you subscribe to the advanced services – maybe you also get better EPG content on those channels!

The PVR function does work. I did manual and scheduled recordings, and the reserve function also works (this just switches to the show instead of recording it).

Safer Alarm – 7400 competition entry

There are several situations where common alarm systems fail to provide any indication that something bad has happened, such as the limited time sirens can sound. This varies according to your local/country regulations, and but when you return, the siren will most likely be off.

Alarm strobes, if fitted are highly visible deterrents, but:

generally provide no external fail safe indication
no indication if power totally fails
relatively heavy power use, so require a significant battery

Alarm strobe lights can run from battery and be left on for long time, but if the the power has been cut off, will your alarm survive without power during your annual holidays?

This system provides a simple, effective and practical enhancement to existing alarm systems to tell you if your alarm has been triggered, tampered with, or lost power. It has been designed to minimise risks by:

giving a safe to enter signal (Green led ONLY)
has fail sale indication (NO indicator = issue)
indicates if alarm system has been tripped (Red led)
indicates if the alarm system has totally lost power (Yellow LED)
can survive on it’s own power for 2+ months

The schematic is shown below, and the Eagle version is here.

Informal testing has shown this circuit works well. It also survived 7+ weeks without power and around fifteen to twenty tests of the indicators.

Further testing using an Arduino and LiveGraph software shows a ‘pretty’ graph of the charging of the super capacitor. I also wrote lots of test code to capture the discharge cycle and occasionally turn on the LEDs, but this went badly wrong as the Arduino test circuit injected power into the system via the flip flop inputs when it was logging, or drained power from the system when left connected, but switched off.

safer alarm test setupCharging the supercap (LiveGraph)

I have just started an open source project to get community help to take this project further. If this project was awarded any prizes,they would be used to encourage further community input to this project (and not given to me or my family, friends, relatives).

Further enhancements could include the use of a pico power AtTiny PIC, this would also open opportunities for more enhancements, including more indicators or count of times alarm triggered, and remote indication, whilst keeping low price and matching input signals to typical alarm active collector active low outputs.

OCN cable TV and set top box (STB) remote control – english labels

I wanted to relax and watch some cable TV in Shanghai. But the remote was all in Chinese. I could see that there was an EPG (on screen TV guide) and also PVR functionality (recording to USB disk), but I could not work out most of the functions. Neither the manual or OCN website was any help with my very poor Chinese, so with a lot of searching I found these button names and with the help of a Shanghainese friend, we worked out which button was which and created the following:

OCN remote control with english text labels

A second post is in the works to explain how to change the onscreen menu language, and briefly describing some of the additional content (English for dummies like me) that you can then find.

Hope this helps someone 🙂

My projects from way back in time

Way back before I had a ‘real’ job I explored lots of stuff.

The workbench with several projects:

On the left in front of that monitor (orange monochrome!) is a built from scratch MicroBee computer.

It’s predecessor is in the 19inch rack box second from the right. This started life as home design Z80 computer with own BIOS (hand entered via switch bank, then via keyboard), then it transformed into an S100 bus system, and then a MicroBee computer was built onto one S100 board!

Back right is my own design linear power supply 0-20V and variable current limit. There is some test gear – custom built function generator so many addons – can’t remember, and a kit frequency counter, Forth kit computer, scavenged printer board, custom Nicad battery charger.