The Bad Idea Barta Board is an April Fools Day joke which has gone too far! We originally thought it would be funny to have a card with as many leaky batteries as possible, but then we thought, why not actually make it do something too? Well, here it is, as many bad ideas as we could roll into one!
So what is it?
It’s an 8-bit ISA card with a microcontroller, an 8-bit DAC, an amplifier as well as a small speaker. It has room for 16 3.6v rechargeable NiMH or NiCd batteries. If you do not use the charging circuit, then you could install any old corroded batteries! Even batteries harvested from old machines if you like (that was kinda my original idea). It can be powered either from a microUSB cable or the ISA bus itself. For storage, it has a 16megabyte flash ROM chip with over 50 prerecorded messages installed!
Who could these messages be from? I had a few ideas for what it might be able to say, but then I thought it might be funnier if I could get some more familiar voices on-board. So I asked David Murray, Clint Basinger, Christian Simpson & Adrian Black if they would be interested in helping out. They all graciously agreed and now the card is that much cooler! Thanks so much guys!
The front of the card has two switches, one button and a potentiometer. The first switch from the left selects between USB/ISA Bus power or battery power. This may be used as a power switch too, unless you have batteries and another source. The second switch turns the battery charger on or off. You should not turn this switch on while in battery power mode. Likewise, you should not plug the USB cable into the card at the same time as installing it in an ISA slot.
The button has a few purposes. On power-on, if the card is removed from a computer the card will play a random message from the “taunt” or normal playlist. It will play a new random message with each short push. If you hold the button down for one second, the card will toggle between random and sequential play. Then each short push will behave according to the mode.
The potentiometer is used to control the volume level. Generally, you can turn the volume up all the way while on USB or ISA power. Although, the speaker can rattle depending on the song. On battery power it’s best to start low and turn it up a bit to see where it’s happy. The batteries are really not a great match for audio. They are for a clock usually, but 16 of them can actually do ok.
A note on battery charging: As scary as I make it sound in the video, the circuit is actually quite slow to charge the batteries on purpose. It has two options, 50 or 100ma. The default charge current is 50ma, solder jumper JP1 to increase to 100ma. While there are 16 battery outlets available, you need to install in sets of 8 or 16 if you intend to use the charger to keep the charge rate from going too high. Solder JP2 if you wish to use all 16 batteries. If you only use 8, populate batteries BT9 – BT16 first.
There are a few other functions for this card. The microcontroller used is an ATMEGA32u4, which is the same used by an Arduino Leonardo. The USB cable can be plugged into a PC where it will present itself as a serial port. You can use any terminal application to connect to the card and playback any message stored on the card directly. You can also send a 48KHz mono 8-bit WAV data directly through the serial port and stream it on the card!
Everything mentioned above is available on the card as it ships, but I added a bit more code on github which will allow you to upload your own custom messages if you wish! Take a look here for more info: Bad Idea Barta Docs / Code (github.com)
To see a demo and hear it in action! Take a look here: https://youtu.be/JqvdLEKVbyM
Batteries are not included. As it turns out, they are expensive to buy and have many shipping restrictions. Batteries are not required for this board to function, it will work stand-alone via USB or in the slot of an ISA computer. As mentioned in this video, this card will not damage a computer by plugging it in. However, it certainly would not be wise to install 16 batteries on the board, and then leave it a machine for any period of time. This card really has no functionality which would merit leaving it installed long-term.