Home -> Proto Bono

Proto Bono is a free protoboard design. (The name is a play on pro bono)

The cheap one-sided protoboards that most people use for prototypes suck. I’ve wasted many hours fighting against them and I’ve grown to despise them. The contacts peal off when you try to solder them. they’re not through-hole plated, and the contacts aren’t plated so they corrode – making it very difficult to solder a good connection to them. They also don’t have a solder mask, so shorts are a common problem. On top of that, they’re poorly manufactured and not really all that cheap.

protoboards that are a step up from that are available from shops like Sparkfun, and are a reasonbly good solution, but they’re a little pricey, and tend to be either over-featured or under-featured.

So hopefully, for some of you, this board is a good solution. It’s small and designed with all the features you need for atmega48/88/168/328 development built in, along with common features that are handy for prototyping – even non-AVR prototyping. For $99 you can order 33 of them from China – $3 each. I recommend Gold Phoenix. I am not affiliated with them in any way, and I do not make any money if you order from them. Just send them the zip file of Gerbers by following the instructions on their website, and you’ll have some sweet protoboards in about 2 weeks. For an extra $20 you can get a blue, red, yellow, or black soldermask.

Features

• Space for an atmega48/88/168/328 chip, with labeled pins.
• Built in AVR programming headers
• Built in FTDI connectors for serial communication
• Arduino Compatible – turn it into an Arduino clone, everything you need is there. (I’ved tested it with the FTDI cable and it works great, but I can’t seem to get it to work with the Spark fun 3.3V FTDI breakout…)
• Built-in area for suface mount boost circuit for boosting 1, 2, or 3 AA or AAA batteres to 3.3V or 5V. Total cost of the parts for this is ~$2.69. Parts you’ll need:
  • 1 Texas Instruments TPS61070 Boost Converter
  • 2 10 uF Tantalum capacitors (3216-18 package)
  • 1 4.7 uH inductor (1210 package)
  • 1 1 MOhm (for 3.3V) or 1.62 Mohm (for 5V) resistor (0805 package)
  • 1 180KOhm resistor (0805 package)
• Positions for two push buttons
• Two spots for LEDs and their current limiting resistors
• A spot for an optional on/off switch
• A positionsfor one 8-pin SOIC chip
• Use an external resonator or external crystal with caps or just use the AVR’s internal clock.
• GND and VCC busses and a large prototyping area with columns of connected pins – making it easy to add auxilary DIP-packaged chips
• size is 3″ x 1.75″

It’s everything I need for most prototyping, and it saves me 2 or 3 hours of wiring up programming headers and FTDI headers just so I can get started – plus I don’t have to deal with those cheap and frustrating protoboards.

The files are here:

• FreePCB file – Get FreePCB here
• gerber files (zip)
• top silkscreen (png)
• top copper mask (png)
• bottom copper mask (png)

Notes

• The boost circuit sets its target voltage based on the values of R1 and R2. R2 should be 180 KOhm, using 1 MOhm for R1 will boost to 3.3V, using 1.62 MOhm will boost to 5V. The equation for R1 is R1 = 180KOhm * (Vo / 0.5 V – 1). The datasheet for the TI boost chip is here. Surface mount soldering is a little challenging so buy a few spares – especially of the resistors.
• If you want to use the ON/OFF switch but don’t want to use the boost circuit, short the Boost Bypass Jumper pins. (If you don’t need either, you can just connect your power source directly to the Vcc and GND rails)
• The ON/OFF switch only works if you use the one of the GND pins next to the switch for power-in. The switch actually connects these GND pins to common ground when switched on.
• There is a position for a capacitor to connect to AREF if using AVCC as the reference voltage. (the Atmega168 datasheet recommends using a capacitor here if you are using AVCC for AREF). If not using AVCC as AREF, feel free to ignore.
• a VCC pin is located next to the reset pin if you want to connect a pull-up resistor to the reset pin.
• There is a spot for a DTR capacitor if you’re using Arduino. The Arduino schematic puts a 0.1uF capacitor there. I haven’t found that it’s necessary or helpful, but it’s more Arduino compatible.

I’ve made several fixes from the version pictured at the top, including fixing the incorrectly wired buttons, swapping the positions of the resistors and LEDs so that the programming header doesn’t bump into the LED, moving the connection pin for the LEDs to the other side so the wire doesn’t have to run over top of the LED, and the addition of an optional boost circuit for running 3.3 or 5V off a battery.

This work is licensed under a Creative Commons Attribution-Share Alike 3.0 United States License.

You can modify it, you can sell this exact design or one based on it and make $millions, and you can share it, you just have to provide attribution and if you share it you have to share it under the same license.