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geekhack Community => Keyboards => Topic started by: OldIsNew on Wed, 16 August 2017, 23:11:02

Title: Televideo Space Invader Board, Teensy
Post by: OldIsNew on Wed, 16 August 2017, 23:11:02

I've been curious about the Hi-Tek 725 "Space Invader" switches and was able to pick up a Televideo ASCII 935  board (at least I think that's the model based on the back of the PCB) with white linear space invaders on the cheap. I  mapped out the matrix and wired up the Teensy and am now actually able to use it.

[attach=1]            [attach=4]            [attach=2]
 

They're pretty nice linear switches.  While it's certainly not the most attractive board I've ever seen, I overall kind of like it!

[attach=3]

Title: Re: Televideo Space Invader Board, Teensy
Post by: _haru on Thu, 17 August 2017, 00:02:40

That is one HELL of a long spacebar.

Title: Re: Televideo Space Invader Board, Teensy
Post by: fohat.digs on Thu, 17 August 2017, 08:06:32

Does that have the RJ14 connection? Those have proven quite problematic in the past.

Title: Re: Televideo Space Invader Board, Teensy
Post by: OldIsNew on Thu, 17 August 2017, 08:41:25

Quote from: fohat.digs on Thu, 17 August 2017, 08:06:32

Does that have the RJ14 connection? Those have proven quite problematic in the past.

I didn't think to post a pic of the connector before. It is a RJ type connector:

[attach=1]          [attach=2]


 

Title: Re: Televideo Space Invader Board, Teensy
Post by: fohat.digs on Thu, 17 August 2017, 08:50:13

I have been through several Televideos, the only one that I was able to get working was one where the pins were labeled on the controller and I could clearly see data, clock, power, ground, etc. The rest have proven to use wildly different protocol.

Title: Re: Televideo Space Invader Board, Teensy
Post by: Touch_It on Thu, 17 August 2017, 09:03:00

Ahh the Medium Ass Enter.  When you cant decide if BAE or ANSI.

Title: Re: Televideo Space Invader Board, Teensy
Post by: OldIsNew on Thu, 17 August 2017, 09:25:13

Quote from: fohat.digs on Thu, 17 August 2017, 08:50:13

I have been through several Televideos, the only one that I was able to get working was one where the pins were labeled on the controller and I could clearly see data, clock, power, ground, etc. The rest have proven to use wildly different protocol.

I wasn't able to find out much about the board's protocol. I just went ahead and bypassed the whole issue by mapping out the matrix with a multimeter, desoldering the IC's and wiring the the appropriate matrix row/column IC pads to the Teensy. Maybe that approach is kind of "cheating" in a way but I wanted to use the board and hey it worked.

Title: Re: Televideo Space Invader Board, Teensy
Post by: 0100010 on Thu, 17 August 2017, 10:17:19

Quote from: OldIsNew on Thu, 17 August 2017, 09:25:13

Quote from: fohat.digs on Thu, 17 August 2017, 08:50:13

I have been through several Televideos, the only one that I was able to get working was one where the pins were labeled on the controller and I could clearly see data, clock, power, ground, etc. The rest have proven to use wildly different protocol.

I wasn't able to find out much about the board's protocol. I just went ahead and bypassed the whole issue by mapping out the matrix with a multimeter, desoldering the IC's and wiring the the appropriate matrix row/column IC pads to the Teensy. Maybe that approach is kind of "cheating" in a way but I wanted to use the board and hey it worked.

(http://i0.kym-cdn.com/entries/icons/facebook/000/004/128/BRILLIANT_.jpg)